Merge "Remove patchset number from the file path in comments tab"
diff --git a/WORKSPACE b/WORKSPACE
index 47c3e9c..41d6ef8 100644
--- a/WORKSPACE
+++ b/WORKSPACE
@@ -49,49 +49,25 @@
 # otherwise refer to RBE docs.
 rbe_autoconfig(name = "rbe_default")
 
-# TODO(davido): Switch to upstream again, when this PR is merged:
-# https://github.com/bazelbuild/rules_closure/pull/478
 http_archive(
-    name = "io_bazel_rules_closure",
-    sha256 = "b9c2bc6ba377aa497eb7c31681d34404febf9d4e3c9c7d98ce0d78238a0af20f",
-    strip_prefix = "rules_closure-0.31",
+    name = "com_google_protobuf",
+    sha256 = "71030a04aedf9f612d2991c1c552317038c3c5a2b578ac4745267a45e7037c29",
+    strip_prefix = "protobuf-3.12.3",
     urls = [
-        "https://github.com/davido/rules_closure/archive/V0.31.tar.gz",
-        "https://gerrit-ci.gerritforge.com/lib/V0.31.tar.gz",
+        "https://github.com/protocolbuffers/protobuf/archive/v3.12.3.tar.gz",
     ],
 )
 
+load("@com_google_protobuf//:protobuf_deps.bzl", "protobuf_deps")
+
+protobuf_deps()
+
 http_archive(
     name = "build_bazel_rules_nodejs",
     sha256 = "84abf7ac4234a70924628baa9a73a5a5cbad944c4358cf9abdb4aab29c9a5b77",
     urls = ["https://github.com/bazelbuild/rules_nodejs/releases/download/1.7.0/rules_nodejs-1.7.0.tar.gz"],
 )
 
-# File is specific to Polymer and copied from the Closure Github -- should be
-# synced any time there are major changes to Polymer.
-# https://github.com/google/closure-compiler/blob/master/contrib/externs/polymer-1.0.js
-http_file(
-    name = "polymer_closure",
-    downloaded_file_path = "polymer_closure.js",
-    sha256 = "4d63a36dcca040475bd6deb815b9a600bd686e1413ac1ebd4b04516edd675020",
-    urls = ["https://raw.githubusercontent.com/google/closure-compiler/35d2b3340ff23a69441f10fa3bc820691c2942f2/contrib/externs/polymer-1.0.js"],
-)
-
-load("@io_bazel_rules_closure//closure:repositories.bzl", "rules_closure_dependencies", "rules_closure_toolchains")
-
-# Prevent redundant loading of dependencies.
-# TODO(davido): Omit re-fetching ancient args4j version when these PRs are merged:
-# https://github.com/bazelbuild/rules_closure/pull/262
-# https://github.com/google/closure-templates/pull/155
-rules_closure_dependencies(
-    omit_aopalliance = True,
-    omit_bazel_skylib = True,
-    omit_javax_inject = True,
-    omit_rules_cc = True,
-)
-
-rules_closure_toolchains()
-
 # Golang support for PolyGerrit local dev server.
 http_archive(
     name = "io_bazel_rules_go",
@@ -328,7 +304,7 @@
 )
 
 maven_jar(
-    name = "args4j-intern",
+    name = "args4j",
     artifact = "args4j:args4j:2.33",
     sha1 = "bd87a75374a6d6523de82fef51fc3cfe9baf9fc9",
 )
@@ -993,6 +969,45 @@
     sha1 = "639033469776fd37c08358c6b92a4761feb2af4b",
 )
 
+load("@build_bazel_rules_nodejs//:index.bzl", "yarn_install")
+
+yarn_install(
+    name = "npm",
+    package_json = "//:package.json",
+    yarn_lock = "//:yarn.lock",
+)
+
+yarn_install(
+    name = "ui_npm",
+    args = ["--prod"],
+    package_json = "//:polygerrit-ui/app/package.json",
+    yarn_lock = "//:polygerrit-ui/app/yarn.lock",
+)
+
+yarn_install(
+    name = "ui_dev_npm",
+    package_json = "//:polygerrit-ui/package.json",
+    yarn_lock = "//:polygerrit-ui/yarn.lock",
+)
+
+yarn_install(
+    name = "tools_npm",
+    package_json = "//:tools/node_tools/package.json",
+    yarn_lock = "//:tools/node_tools/yarn.lock",
+)
+
+yarn_install(
+    name = "plugins_npm",
+    args = ["--prod"],
+    package_json = "//:plugins/package.json",
+    yarn_lock = "//:plugins/yarn.lock",
+)
+
+# Install all Bazel dependencies needed for npm packages that supply Bazel rules
+load("@npm//:install_bazel_dependencies.bzl", "install_bazel_dependencies")
+
+install_bazel_dependencies()
+
 load("//tools/bzl:js.bzl", "bower_archive", "npm_binary")
 
 # NPM binaries bundled along with their dependencies.
@@ -1184,45 +1199,6 @@
     version = "6.5.1",
 )
 
-load("@build_bazel_rules_nodejs//:index.bzl", "yarn_install")
-
-yarn_install(
-    name = "npm",
-    package_json = "//:package.json",
-    yarn_lock = "//:yarn.lock",
-)
-
-yarn_install(
-    name = "ui_npm",
-    args = ["--prod"],
-    package_json = "//:polygerrit-ui/app/package.json",
-    yarn_lock = "//:polygerrit-ui/app/yarn.lock",
-)
-
-yarn_install(
-    name = "ui_dev_npm",
-    package_json = "//:polygerrit-ui/package.json",
-    yarn_lock = "//:polygerrit-ui/yarn.lock",
-)
-
-yarn_install(
-    name = "tools_npm",
-    package_json = "//:tools/node_tools/package.json",
-    yarn_lock = "//:tools/node_tools/yarn.lock",
-)
-
-yarn_install(
-    name = "plugins_npm",
-    args = ["--prod"],
-    package_json = "//:plugins/package.json",
-    yarn_lock = "//:plugins/yarn.lock",
-)
-
-# Install all Bazel dependencies needed for npm packages that supply Bazel rules
-load("@npm//:install_bazel_dependencies.bzl", "install_bazel_dependencies")
-
-install_bazel_dependencies()
-
 load("@npm_bazel_typescript//:index.bzl", "ts_setup_workspace")
 
 ts_setup_workspace()
diff --git a/java/com/google/gerrit/acceptance/AbstractDaemonTest.java b/java/com/google/gerrit/acceptance/AbstractDaemonTest.java
index 10a8852..dfb7a55 100644
--- a/java/com/google/gerrit/acceptance/AbstractDaemonTest.java
+++ b/java/com/google/gerrit/acceptance/AbstractDaemonTest.java
@@ -983,7 +983,7 @@
   protected void setUseSignedOffBy(InheritableBoolean value) throws Exception {
     try (MetaDataUpdate md = metaDataUpdateFactory.create(project)) {
       ProjectConfig config = projectConfigFactory.read(md);
-      config.getProject().setBooleanConfig(BooleanProjectConfig.USE_SIGNED_OFF_BY, value);
+      config.updateProject(p -> p.setBooleanConfig(BooleanProjectConfig.USE_SIGNED_OFF_BY, value));
       config.commit(md);
       projectCache.evict(config.getProject());
     }
@@ -992,7 +992,7 @@
   protected void setRequireChangeId(InheritableBoolean value) throws Exception {
     try (MetaDataUpdate md = metaDataUpdateFactory.create(project)) {
       ProjectConfig config = projectConfigFactory.read(md);
-      config.getProject().setBooleanConfig(BooleanProjectConfig.REQUIRE_CHANGE_ID, value);
+      config.updateProject(p -> p.setBooleanConfig(BooleanProjectConfig.REQUIRE_CHANGE_ID, value));
       config.commit(md);
       projectCache.evict(config.getProject());
     }
@@ -1442,10 +1442,10 @@
       LabelValue... value)
       throws Exception {
     try (ProjectConfigUpdate u = updateProject(project)) {
-      LabelType labelType = label(label, value);
+      LabelType.Builder labelType = label(label, value).toBuilder();
       labelType.setFunction(func);
-      labelType.setRefPatterns(refPatterns);
-      u.getConfig().getLabelSections().put(labelType.getName(), labelType);
+      labelType.setRefPatterns(ImmutableList.copyOf(refPatterns));
+      u.getConfig().upsertLabelType(labelType.build());
       u.save();
     }
   }
@@ -1453,10 +1453,11 @@
   protected void enableCreateNewChangeForAllNotInTarget() throws Exception {
     try (ProjectConfigUpdate u = updateProject(project)) {
       u.getConfig()
-          .getProject()
-          .setBooleanConfig(
-              BooleanProjectConfig.CREATE_NEW_CHANGE_FOR_ALL_NOT_IN_TARGET,
-              InheritableBoolean.TRUE);
+          .updateProject(
+              p ->
+                  p.setBooleanConfig(
+                      BooleanProjectConfig.CREATE_NEW_CHANGE_FOR_ALL_NOT_IN_TARGET,
+                      InheritableBoolean.TRUE));
       u.save();
     }
   }
diff --git a/java/com/google/gerrit/common/data/LabelType.java b/java/com/google/gerrit/common/data/LabelType.java
index 3a68414..9c1423d 100644
--- a/java/com/google/gerrit/common/data/LabelType.java
+++ b/java/com/google/gerrit/common/data/LabelType.java
@@ -14,23 +14,21 @@
 
 package com.google.gerrit.common.data;
 
-import static com.google.common.collect.ImmutableList.toImmutableList;
 import static java.util.Comparator.comparing;
-import static java.util.stream.Collectors.collectingAndThen;
 import static java.util.stream.Collectors.toList;
 
+import com.google.auto.value.AutoValue;
 import com.google.common.collect.ImmutableList;
+import com.google.common.collect.ImmutableMap;
 import com.google.gerrit.common.Nullable;
 import com.google.gerrit.entities.LabelId;
 import com.google.gerrit.entities.PatchSetApproval;
 import java.util.ArrayList;
 import java.util.Collection;
-import java.util.Collections;
-import java.util.HashMap;
 import java.util.List;
-import java.util.Map;
 
-public class LabelType {
+@AutoValue
+public abstract class LabelType {
   public static final boolean DEF_ALLOW_POST_SUBMIT = true;
   public static final boolean DEF_CAN_OVERRIDE = true;
   public static final boolean DEF_COPY_ALL_SCORES_IF_NO_CHANGE = true;
@@ -46,12 +44,12 @@
   public static LabelType withDefaultValues(String name) {
     checkName(name);
     List<LabelValue> values = new ArrayList<>(2);
-    values.add(new LabelValue((short) 0, "Rejected"));
-    values.add(new LabelValue((short) 1, "Approved"));
-    return new LabelType(name, values);
+    values.add(LabelValue.create((short) 0, "Rejected"));
+    values.add(LabelValue.create((short) 1, "Approved"));
+    return create(name, values);
   }
 
-  public static String checkName(String name) {
+  public static String checkName(String name) throws IllegalArgumentException {
     checkNameInternal(name);
     if ("SUBM".equals(name)) {
       throw new IllegalArgumentException("Reserved label name \"" + name + "\"");
@@ -59,7 +57,7 @@
     return name;
   }
 
-  public static String checkNameInternal(String name) {
+  public static String checkNameInternal(String name) throws IllegalArgumentException {
     if (name == null || name.isEmpty()) {
       throw new IllegalArgumentException("Empty label name");
     }
@@ -76,270 +74,135 @@
     return name;
   }
 
-  private static List<LabelValue> sortValues(List<LabelValue> values) {
-    values = new ArrayList<>(values);
+  private static ImmutableList<LabelValue> sortValues(List<LabelValue> values) {
     if (values.isEmpty()) {
-      return Collections.emptyList();
+      return ImmutableList.of();
     }
     values = values.stream().sorted(comparing(LabelValue::getValue)).collect(toList());
     short v = values.get(0).getValue();
     short i = 0;
-    ArrayList<LabelValue> result = new ArrayList<>();
+    ImmutableList.Builder<LabelValue> result = ImmutableList.builder();
     // Fill in any missing values with empty text.
     while (i < values.size()) {
       while (v < values.get(i).getValue()) {
-        result.add(new LabelValue(v++, ""));
+        result.add(LabelValue.create(v++, ""));
       }
       v++;
       result.add(values.get(i++));
     }
-    result.trimToSize();
-    return Collections.unmodifiableList(result);
+    return result.build();
   }
 
-  protected String name;
+  public abstract String getName();
 
-  protected LabelFunction function;
+  public abstract LabelFunction getFunction();
 
-  protected boolean copyAnyScore;
-  protected boolean copyMinScore;
-  protected boolean copyMaxScore;
-  protected boolean copyAllScoresOnMergeFirstParentUpdate;
-  protected boolean copyAllScoresOnTrivialRebase;
-  protected boolean copyAllScoresIfNoCodeChange;
-  protected boolean copyAllScoresIfNoChange;
-  protected ImmutableList<Short> copyValues;
-  protected boolean allowPostSubmit;
-  protected boolean ignoreSelfApproval;
-  protected short defaultValue;
+  public abstract boolean isCopyAnyScore();
 
-  protected List<LabelValue> values;
-  protected short maxNegative;
-  protected short maxPositive;
+  public abstract boolean isCopyMinScore();
 
-  private transient boolean canOverride;
-  private transient List<String> refPatterns;
-  private transient Map<Short, LabelValue> byValue;
+  public abstract boolean isCopyMaxScore();
 
-  protected LabelType() {}
+  public abstract boolean isCopyAllScoresOnMergeFirstParentUpdate();
 
-  public LabelType(String name, List<LabelValue> valueList) {
-    this.name = checkName(name);
-    canOverride = true;
-    values = sortValues(valueList);
-    defaultValue = 0;
+  public abstract boolean isCopyAllScoresOnTrivialRebase();
 
-    function = LabelFunction.MAX_WITH_BLOCK;
+  public abstract boolean isCopyAllScoresIfNoCodeChange();
 
-    maxNegative = Short.MIN_VALUE;
-    maxPositive = Short.MAX_VALUE;
-    if (!values.isEmpty()) {
-      if (values.get(0).getValue() < 0) {
-        maxNegative = values.get(0).getValue();
-      }
-      if (values.get(values.size() - 1).getValue() > 0) {
-        maxPositive = values.get(values.size() - 1).getValue();
-      }
-    }
-    setCanOverride(DEF_CAN_OVERRIDE);
-    setCopyAllScoresIfNoChange(DEF_COPY_ALL_SCORES_IF_NO_CHANGE);
-    setCopyAllScoresIfNoCodeChange(DEF_COPY_ALL_SCORES_IF_NO_CODE_CHANGE);
-    setCopyAllScoresOnTrivialRebase(DEF_COPY_ALL_SCORES_ON_TRIVIAL_REBASE);
-    setCopyAllScoresOnMergeFirstParentUpdate(DEF_COPY_ALL_SCORES_ON_MERGE_FIRST_PARENT_UPDATE);
-    setCopyAnyScore(DEF_COPY_ANY_SCORE);
-    setCopyMaxScore(DEF_COPY_MAX_SCORE);
-    setCopyMinScore(DEF_COPY_MIN_SCORE);
-    setCopyValues(DEF_COPY_VALUES);
-    setAllowPostSubmit(DEF_ALLOW_POST_SUBMIT);
-    setIgnoreSelfApproval(DEF_IGNORE_SELF_APPROVAL);
+  public abstract boolean isCopyAllScoresIfNoChange();
 
-    byValue = new HashMap<>();
-    for (LabelValue v : values) {
-      byValue.put(v.getValue(), v);
-    }
+  public abstract ImmutableList<Short> getCopyValues();
+
+  public abstract boolean isAllowPostSubmit();
+
+  public abstract boolean isIgnoreSelfApproval();
+
+  public abstract short getDefaultValue();
+
+  public abstract ImmutableList<LabelValue> getValues();
+
+  public abstract short getMaxNegative();
+
+  public abstract short getMaxPositive();
+
+  public abstract boolean isCanOverride();
+
+  @Nullable
+  public abstract ImmutableList<String> getRefPatterns();
+
+  public abstract ImmutableMap<Short, LabelValue> getByValue();
+
+  public static LabelType create(String name, List<LabelValue> valueList) {
+    return LabelType.builder(name, valueList).build();
   }
 
-  public String getName() {
-    return name;
-  }
-
-  public void setName(String name) {
-    this.name = checkName(name);
+  public static LabelType.Builder builder(String name, List<LabelValue> valueList) {
+    return (new AutoValue_LabelType.Builder())
+        .setName(name)
+        .setValues(valueList)
+        .setDefaultValue((short) 0)
+        .setFunction(LabelFunction.MAX_WITH_BLOCK)
+        .setMaxNegative(Short.MIN_VALUE)
+        .setMaxPositive(Short.MAX_VALUE)
+        .setCanOverride(DEF_CAN_OVERRIDE)
+        .setCopyAllScoresIfNoChange(DEF_COPY_ALL_SCORES_IF_NO_CHANGE)
+        .setCopyAllScoresIfNoCodeChange(DEF_COPY_ALL_SCORES_IF_NO_CODE_CHANGE)
+        .setCopyAllScoresOnTrivialRebase(DEF_COPY_ALL_SCORES_ON_TRIVIAL_REBASE)
+        .setCopyAllScoresOnMergeFirstParentUpdate(DEF_COPY_ALL_SCORES_ON_MERGE_FIRST_PARENT_UPDATE)
+        .setCopyAnyScore(DEF_COPY_ANY_SCORE)
+        .setCopyMaxScore(DEF_COPY_MAX_SCORE)
+        .setCopyMinScore(DEF_COPY_MIN_SCORE)
+        .setCopyValues(DEF_COPY_VALUES)
+        .setAllowPostSubmit(DEF_ALLOW_POST_SUBMIT)
+        .setIgnoreSelfApproval(DEF_IGNORE_SELF_APPROVAL);
   }
 
   public boolean matches(PatchSetApproval psa) {
-    return psa.labelId().get().equalsIgnoreCase(name);
-  }
-
-  public LabelFunction getFunction() {
-    return function;
-  }
-
-  public void setFunction(@Nullable LabelFunction function) {
-    this.function = function;
-  }
-
-  public boolean canOverride() {
-    return canOverride;
-  }
-
-  @Nullable
-  public List<String> getRefPatterns() {
-    return refPatterns;
-  }
-
-  public void setCanOverride(boolean canOverride) {
-    this.canOverride = canOverride;
-  }
-
-  public boolean allowPostSubmit() {
-    return allowPostSubmit;
-  }
-
-  public void setAllowPostSubmit(boolean allowPostSubmit) {
-    this.allowPostSubmit = allowPostSubmit;
-  }
-
-  public boolean ignoreSelfApproval() {
-    return ignoreSelfApproval;
-  }
-
-  public void setIgnoreSelfApproval(boolean ignoreSelfApproval) {
-    this.ignoreSelfApproval = ignoreSelfApproval;
-  }
-
-  public void setRefPatterns(List<String> refPatterns) {
-    if (refPatterns != null && !refPatterns.isEmpty()) {
-      this.refPatterns =
-          refPatterns.stream().collect(collectingAndThen(toList(), Collections::unmodifiableList));
-    } else {
-      this.refPatterns = null;
-    }
-  }
-
-  public List<LabelValue> getValues() {
-    return values;
-  }
-
-  public void setValues(List<LabelValue> values) {
-    this.values = sortValues(values);
+    return psa.labelId().get().equalsIgnoreCase(getName());
   }
 
   public LabelValue getMin() {
-    if (values.isEmpty()) {
+    if (getValues().isEmpty()) {
       return null;
     }
-    return values.get(0);
+    return getValues().get(0);
   }
 
   public LabelValue getMax() {
-    if (values.isEmpty()) {
+    if (getValues().isEmpty()) {
       return null;
     }
-    return values.get(values.size() - 1);
-  }
-
-  public short getDefaultValue() {
-    return defaultValue;
-  }
-
-  public void setDefaultValue(short defaultValue) {
-    this.defaultValue = defaultValue;
-  }
-
-  public boolean isCopyAnyScore() {
-    return copyAnyScore;
-  }
-
-  public void setCopyAnyScore(boolean copyAnyScore) {
-    this.copyAnyScore = copyAnyScore;
-  }
-
-  public boolean isCopyMinScore() {
-    return copyMinScore;
-  }
-
-  public void setCopyMinScore(boolean copyMinScore) {
-    this.copyMinScore = copyMinScore;
-  }
-
-  public boolean isCopyMaxScore() {
-    return copyMaxScore;
-  }
-
-  public void setCopyMaxScore(boolean copyMaxScore) {
-    this.copyMaxScore = copyMaxScore;
-  }
-
-  public boolean isCopyAllScoresOnMergeFirstParentUpdate() {
-    return copyAllScoresOnMergeFirstParentUpdate;
-  }
-
-  public void setCopyAllScoresOnMergeFirstParentUpdate(
-      boolean copyAllScoresOnMergeFirstParentUpdate) {
-    this.copyAllScoresOnMergeFirstParentUpdate = copyAllScoresOnMergeFirstParentUpdate;
-  }
-
-  public boolean isCopyAllScoresOnTrivialRebase() {
-    return copyAllScoresOnTrivialRebase;
-  }
-
-  public void setCopyAllScoresOnTrivialRebase(boolean copyAllScoresOnTrivialRebase) {
-    this.copyAllScoresOnTrivialRebase = copyAllScoresOnTrivialRebase;
-  }
-
-  public boolean isCopyAllScoresIfNoCodeChange() {
-    return copyAllScoresIfNoCodeChange;
-  }
-
-  public void setCopyAllScoresIfNoCodeChange(boolean copyAllScoresIfNoCodeChange) {
-    this.copyAllScoresIfNoCodeChange = copyAllScoresIfNoCodeChange;
-  }
-
-  public boolean isCopyAllScoresIfNoChange() {
-    return copyAllScoresIfNoChange;
-  }
-
-  public void setCopyAllScoresIfNoChange(boolean copyAllScoresIfNoChange) {
-    this.copyAllScoresIfNoChange = copyAllScoresIfNoChange;
-  }
-
-  public ImmutableList<Short> getCopyValues() {
-    return copyValues;
-  }
-
-  public void setCopyValues(Collection<Short> copyValues) {
-    this.copyValues = copyValues.stream().sorted().collect(toImmutableList());
+    return getValues().get(getValues().size() - 1);
   }
 
   public boolean isMaxNegative(PatchSetApproval ca) {
-    return maxNegative == ca.value();
+    return getMaxNegative() == ca.value();
   }
 
   public boolean isMaxPositive(PatchSetApproval ca) {
-    return maxPositive == ca.value();
+    return getMaxPositive() == ca.value();
   }
 
   public LabelValue getValue(short value) {
-    return byValue.get(value);
+    return getByValue().get(value);
   }
 
   public LabelValue getValue(PatchSetApproval ca) {
-    return byValue.get(ca.value());
+    return getByValue().get(ca.value());
   }
 
   public LabelId getLabelId() {
-    return LabelId.create(name);
+    return LabelId.create(getName());
   }
 
   @Override
-  public String toString() {
-    StringBuilder sb = new StringBuilder(name).append('[');
+  public final String toString() {
+    StringBuilder sb = new StringBuilder(getName()).append('[');
     LabelValue min = getMin();
     LabelValue max = getMax();
     if (min != null && max != null) {
       sb.append(
-          new PermissionRange(Permission.forLabel(name), min.getValue(), max.getValue())
+          new PermissionRange(Permission.forLabel(getName()), min.getValue(), max.getValue())
               .toString()
               .trim());
     } else if (min != null) {
@@ -350,4 +213,84 @@
     sb.append(']');
     return sb.toString();
   }
+
+  public abstract Builder toBuilder();
+
+  @AutoValue.Builder
+  public abstract static class Builder {
+    public abstract Builder setName(String name);
+
+    public abstract Builder setFunction(LabelFunction function);
+
+    public abstract Builder setCanOverride(boolean canOverride);
+
+    public abstract Builder setAllowPostSubmit(boolean allowPostSubmit);
+
+    public abstract Builder setIgnoreSelfApproval(boolean ignoreSelfApproval);
+
+    public abstract Builder setRefPatterns(@Nullable ImmutableList<String> refPatterns);
+
+    public abstract Builder setValues(List<LabelValue> values);
+
+    public abstract Builder setDefaultValue(short defaultValue);
+
+    public abstract Builder setCopyAnyScore(boolean copyAnyScore);
+
+    public abstract Builder setCopyMinScore(boolean copyMinScore);
+
+    public abstract Builder setCopyMaxScore(boolean copyMaxScore);
+
+    public abstract Builder setCopyAllScoresOnMergeFirstParentUpdate(
+        boolean copyAllScoresOnMergeFirstParentUpdate);
+
+    public abstract Builder setCopyAllScoresOnTrivialRebase(boolean copyAllScoresOnTrivialRebase);
+
+    public abstract Builder setCopyAllScoresIfNoCodeChange(boolean copyAllScoresIfNoCodeChange);
+
+    public abstract Builder setCopyAllScoresIfNoChange(boolean copyAllScoresIfNoChange);
+
+    public abstract Builder setCopyValues(Collection<Short> copyValues);
+
+    public abstract Builder setMaxNegative(short maxNegative);
+
+    public abstract Builder setMaxPositive(short maxPositive);
+
+    public abstract ImmutableList<LabelValue> getValues();
+
+    protected abstract String getName();
+
+    protected abstract Builder setByValue(ImmutableMap<Short, LabelValue> byValue);
+
+    @Nullable
+    protected abstract ImmutableList<String> getRefPatterns();
+
+    protected abstract LabelType autoBuild();
+
+    public LabelType build() throws IllegalArgumentException {
+      setName(checkName(getName()));
+      if (getRefPatterns() == null || getRefPatterns().isEmpty()) {
+        // Empty to null
+        setRefPatterns(null);
+      }
+
+      List<LabelValue> valueList = sortValues(getValues());
+      setValues(valueList);
+      if (!valueList.isEmpty()) {
+        if (valueList.get(0).getValue() < 0) {
+          setMaxNegative(valueList.get(0).getValue());
+        }
+        if (valueList.get(valueList.size() - 1).getValue() > 0) {
+          setMaxPositive(valueList.get(valueList.size() - 1).getValue());
+        }
+      }
+
+      ImmutableMap.Builder<Short, LabelValue> byValue = ImmutableMap.builder();
+      for (LabelValue v : valueList) {
+        byValue.put(v.getValue(), v);
+      }
+      setByValue(byValue.build());
+
+      return autoBuild();
+    }
+  }
 }
diff --git a/java/com/google/gerrit/common/data/LabelValue.java b/java/com/google/gerrit/common/data/LabelValue.java
index c0ba781..ec16fb2 100644
--- a/java/com/google/gerrit/common/data/LabelValue.java
+++ b/java/com/google/gerrit/common/data/LabelValue.java
@@ -14,65 +14,42 @@
 
 package com.google.gerrit.common.data;
 
-import java.util.Objects;
+import com.google.auto.value.AutoValue;
 
-public class LabelValue {
+@AutoValue
+public abstract class LabelValue {
   public static String formatValue(short value) {
     if (value < 0) {
       return Short.toString(value);
     } else if (value == 0) {
       return " 0";
     } else {
-      return "+" + Short.toString(value);
+      return "+" + value;
     }
   }
 
-  protected short value;
-  protected String text;
+  public abstract short getValue();
 
-  public LabelValue(short value, String text) {
-    this.value = value;
-    this.text = text;
-  }
+  public abstract String getText();
 
-  protected LabelValue() {}
-
-  public short getValue() {
-    return value;
-  }
-
-  public String getText() {
-    return text;
+  public static LabelValue create(short value, String text) {
+    return new AutoValue_LabelValue(value, text);
   }
 
   public String formatValue() {
-    return formatValue(value);
+    return formatValue(getValue());
   }
 
   public String format() {
     StringBuilder sb = new StringBuilder(formatValue());
-    if (!text.isEmpty()) {
-      sb.append(' ').append(text);
+    if (!getText().isEmpty()) {
+      sb.append(' ').append(getText());
     }
     return sb.toString();
   }
 
   @Override
-  public boolean equals(Object o) {
-    if (!(o instanceof LabelValue)) {
-      return false;
-    }
-    LabelValue v = (LabelValue) o;
-    return value == v.value && Objects.equals(text, v.text);
-  }
-
-  @Override
-  public int hashCode() {
-    return Objects.hash(value, text);
-  }
-
-  @Override
-  public String toString() {
+  public final String toString() {
     return format();
   }
 }
diff --git a/java/com/google/gerrit/entities/Project.java b/java/com/google/gerrit/entities/Project.java
index 1300b9d..759d50a 100644
--- a/java/com/google/gerrit/entities/Project.java
+++ b/java/com/google/gerrit/entities/Project.java
@@ -16,7 +16,10 @@
 
 import static java.util.Objects.requireNonNull;
 
+import com.google.auto.value.AutoValue;
+import com.google.common.collect.ImmutableMap;
 import com.google.errorprone.annotations.Immutable;
+import com.google.gerrit.common.Nullable;
 import com.google.gerrit.extensions.client.InheritableBoolean;
 import com.google.gerrit.extensions.client.ProjectState;
 import com.google.gerrit.extensions.client.SubmitType;
@@ -27,7 +30,8 @@
 import java.util.Optional;
 
 /** Projects match a source code repository managed by Gerrit */
-public final class Project {
+@AutoValue
+public abstract class Project {
   /** Default submit type for new projects. */
   public static final SubmitType DEFAULT_SUBMIT_TYPE = SubmitType.MERGE_IF_NECESSARY;
 
@@ -60,10 +64,6 @@
       return nameKey(KeyUtil.decode(str));
     }
 
-    public static String asStringOrNull(NameKey key) {
-      return key == null ? null : key.get();
-    }
-
     private final String name;
 
     protected NameKey(String name) {
@@ -98,118 +98,64 @@
     }
   }
 
-  protected NameKey name;
+  public abstract NameKey getNameKey();
 
-  protected String description;
+  @Nullable
+  public abstract String getDescription();
 
-  protected Map<BooleanProjectConfig, InheritableBoolean> booleanConfigs;
-
-  protected SubmitType submitType;
-
-  protected ProjectState state;
-
-  protected NameKey parent;
-
-  protected String maxObjectSizeLimit;
-
-  protected String defaultDashboardId;
-
-  protected String localDefaultDashboardId;
-
-  protected String configRefState;
-
-  protected Project() {}
-
-  public Project(Project.NameKey nameKey) {
-    name = nameKey;
-    submitType = SubmitType.MERGE_IF_NECESSARY;
-    state = ProjectState.ACTIVE;
-
-    booleanConfigs = new HashMap<>();
-    Arrays.stream(BooleanProjectConfig.values())
-        .forEach(c -> booleanConfigs.put(c, InheritableBoolean.INHERIT));
-  }
-
-  public Project.NameKey getNameKey() {
-    return name;
-  }
-
-  public String getName() {
-    return name != null ? name.get() : null;
-  }
-
-  public String getDescription() {
-    return description;
-  }
-
-  public void setDescription(String d) {
-    description = d;
-  }
-
-  public String getMaxObjectSizeLimit() {
-    return maxObjectSizeLimit;
-  }
-
-  public InheritableBoolean getBooleanConfig(BooleanProjectConfig config) {
-    return booleanConfigs.get(config);
-  }
-
-  public void setBooleanConfig(BooleanProjectConfig config, InheritableBoolean val) {
-    booleanConfigs.replace(config, val);
-  }
-
-  public void setMaxObjectSizeLimit(String limit) {
-    maxObjectSizeLimit = limit;
-  }
+  protected abstract ImmutableMap<BooleanProjectConfig, InheritableBoolean> getBooleanConfigs();
 
   /**
    * Submit type as configured in {@code project.config}.
    *
    * <p>Does not take inheritance into account, i.e. may return {@link SubmitType#INHERIT}.
-   *
-   * @return submit type.
    */
-  public SubmitType getConfiguredSubmitType() {
-    return submitType;
-  }
+  public abstract SubmitType getSubmitType();
 
-  public void setSubmitType(SubmitType type) {
-    submitType = type;
-  }
-
-  public ProjectState getState() {
-    return state;
-  }
-
-  public void setState(ProjectState newState) {
-    state = newState;
-  }
-
-  public String getDefaultDashboard() {
-    return defaultDashboardId;
-  }
-
-  public void setDefaultDashboard(String defaultDashboardId) {
-    this.defaultDashboardId = defaultDashboardId;
-  }
-
-  public String getLocalDefaultDashboard() {
-    return localDefaultDashboardId;
-  }
-
-  public void setLocalDefaultDashboard(String localDefaultDashboardId) {
-    this.localDefaultDashboardId = localDefaultDashboardId;
-  }
+  public abstract ProjectState getState();
 
   /**
-   * Returns the name key of the parent project.
+   * Name key of the parent project.
    *
-   * @return name key of the parent project, {@code null} if this project is the wild project,
-   *     {@code null} or the name key of the wild project if this project is a direct child of the
-   *     wild project
+   * <p>{@code null} if this project is the wild project, {@code null} or the name key of the wild
+   * project if this project is a direct child of the wild project.
    */
-  public Project.NameKey getParent() {
-    return parent;
+  @Nullable
+  public abstract NameKey getParent();
+
+  @Nullable
+  public abstract String getMaxObjectSizeLimit();
+
+  @Nullable
+  public abstract String getDefaultDashboard();
+
+  @Nullable
+  public abstract String getLocalDefaultDashboard();
+
+  /** The {@code ObjectId} as 40 digit hex of {@code refs/meta/config}'s HEAD. */
+  @Nullable
+  public abstract String getConfigRefState();
+
+  public static Builder builder(Project.NameKey nameKey) {
+    Builder builder =
+        new AutoValue_Project.Builder()
+            .setNameKey(nameKey)
+            .setSubmitType(SubmitType.MERGE_IF_NECESSARY)
+            .setState(ProjectState.ACTIVE);
+    ImmutableMap.Builder<BooleanProjectConfig, InheritableBoolean> booleans =
+        ImmutableMap.builder();
+    Arrays.stream(BooleanProjectConfig.values())
+        .forEach(b -> booleans.put(b, InheritableBoolean.INHERIT));
+    builder.setBooleanConfigs(booleans.build());
+    return builder;
+  }
+
+  public String getName() {
+    return getNameKey() != null ? getNameKey().get() : null;
+  }
+
+  public InheritableBoolean getBooleanConfig(BooleanProjectConfig config) {
+    return getBooleanConfigs().get(config);
   }
 
   /**
@@ -220,11 +166,11 @@
    *     project
    */
   public Project.NameKey getParent(Project.NameKey allProjectsName) {
-    if (parent != null) {
-      return parent;
+    if (getParent() != null) {
+      return getParent();
     }
 
-    if (name.equals(allProjectsName)) {
+    if (getNameKey().equals(allProjectsName)) {
       return null;
     }
 
@@ -232,29 +178,53 @@
   }
 
   public String getParentName() {
-    return parent != null ? parent.get() : null;
-  }
-
-  public void setParentName(String n) {
-    parent = n != null ? nameKey(n) : null;
-  }
-
-  public void setParentName(NameKey n) {
-    parent = n;
-  }
-
-  /** Returns the {@code ObjectId} as 40 digit hex of {@code refs/meta/config}'s HEAD. */
-  public String getConfigRefState() {
-    return configRefState;
-  }
-
-  /** Sets the {@code ObjectId} as 40 digit hex of {@code refs/meta/config}'s HEAD. */
-  public void setConfigRefState(String state) {
-    configRefState = state;
+    return getParent() != null ? getParent().get() : null;
   }
 
   @Override
-  public String toString() {
+  public final String toString() {
     return Optional.of(getName()).orElse("<null>");
   }
+
+  public abstract Builder toBuilder();
+
+  @AutoValue.Builder
+  public abstract static class Builder {
+    public abstract Builder setDescription(String description);
+
+    public Builder setBooleanConfig(BooleanProjectConfig config, InheritableBoolean val) {
+      Map<BooleanProjectConfig, InheritableBoolean> map = new HashMap<>(getBooleanConfigs());
+      map.replace(config, val);
+      setBooleanConfigs(ImmutableMap.copyOf(map));
+      return this;
+    }
+
+    public abstract Builder setMaxObjectSizeLimit(String limit);
+
+    public abstract Builder setSubmitType(SubmitType type);
+
+    public abstract Builder setState(ProjectState newState);
+
+    public abstract Builder setDefaultDashboard(String defaultDashboardId);
+
+    public abstract Builder setLocalDefaultDashboard(String localDefaultDashboard);
+
+    public abstract Builder setParent(NameKey n);
+
+    public Builder setParent(String n) {
+      return setParent(n != null ? nameKey(n) : null);
+    }
+
+    /** Sets the {@code ObjectId} as 40 digit hex of {@code refs/meta/config}'s HEAD. */
+    public abstract Builder setConfigRefState(String state);
+
+    public abstract Project build();
+
+    protected abstract Builder setNameKey(Project.NameKey nameKey);
+
+    protected abstract ImmutableMap<BooleanProjectConfig, InheritableBoolean> getBooleanConfigs();
+
+    protected abstract Builder setBooleanConfigs(
+        ImmutableMap<BooleanProjectConfig, InheritableBoolean> booleanConfigs);
+  }
 }
diff --git a/java/com/google/gerrit/httpd/init/WebAppInitializer.java b/java/com/google/gerrit/httpd/init/WebAppInitializer.java
index 0c3b7b0..c5f97a3 100644
--- a/java/com/google/gerrit/httpd/init/WebAppInitializer.java
+++ b/java/com/google/gerrit/httpd/init/WebAppInitializer.java
@@ -96,6 +96,7 @@
 import com.google.gerrit.server.ssh.NoSshModule;
 import com.google.gerrit.server.ssh.SshAddressesModule;
 import com.google.gerrit.server.submit.LocalMergeSuperSetComputation;
+import com.google.gerrit.server.submit.SubscriptionGraph;
 import com.google.gerrit.sshd.SshHostKeyModule;
 import com.google.gerrit.sshd.SshKeyCacheImpl;
 import com.google.gerrit.sshd.SshModule;
@@ -322,6 +323,7 @@
     }
 
     modules.add(new RestApiModule());
+    modules.add(new SubscriptionGraph.Module());
     modules.add(new WorkQueue.Module());
     modules.add(new GerritInstanceNameModule());
     modules.add(
diff --git a/java/com/google/gerrit/server/change/LabelsJson.java b/java/com/google/gerrit/server/change/LabelsJson.java
index 2db17d6..739e263 100644
--- a/java/com/google/gerrit/server/change/LabelsJson.java
+++ b/java/com/google/gerrit/server/change/LabelsJson.java
@@ -122,7 +122,7 @@
       if (rec.labels != null) {
         for (SubmitRecord.Label r : rec.labels) {
           LabelType type = labelTypes.byLabel(r.label);
-          if (type != null && (!isMerged || type.allowPostSubmit())) {
+          if (type != null && (!isMerged || type.isAllowPostSubmit())) {
             toCheck.put(type.getName(), type);
           }
         }
@@ -139,7 +139,7 @@
       }
       for (SubmitRecord.Label r : rec.labels) {
         LabelType type = labelTypes.byLabel(r.label);
-        if (type == null || (isMerged && !type.allowPostSubmit())) {
+        if (type == null || (isMerged && !type.isAllowPostSubmit())) {
           continue;
         }
 
diff --git a/java/com/google/gerrit/server/git/NotifyConfig.java b/java/com/google/gerrit/server/git/NotifyConfig.java
index 429f15a..1a1bbb6 100644
--- a/java/com/google/gerrit/server/git/NotifyConfig.java
+++ b/java/com/google/gerrit/server/git/NotifyConfig.java
@@ -14,113 +14,101 @@
 
 package com.google.gerrit.server.git;
 
-import com.google.common.base.MoreObjects;
+import com.google.auto.value.AutoValue;
 import com.google.common.base.Strings;
+import com.google.common.collect.ImmutableSet;
 import com.google.gerrit.common.data.GroupReference;
 import com.google.gerrit.mail.Address;
 import com.google.gerrit.server.account.ProjectWatches.NotifyType;
 import java.util.EnumSet;
-import java.util.HashSet;
 import java.util.Set;
+import org.eclipse.jgit.annotations.Nullable;
 
-public class NotifyConfig implements Comparable<NotifyConfig> {
+@AutoValue
+public abstract class NotifyConfig implements Comparable<NotifyConfig> {
   public enum Header {
     TO,
     CC,
     BCC
   }
 
-  private String name;
-  private EnumSet<NotifyType> types = EnumSet.of(NotifyType.ALL);
-  private String filter;
+  @Nullable
+  public abstract String getName();
 
-  private Header header;
-  private Set<GroupReference> groups = new HashSet<>();
-  private Set<Address> addresses = new HashSet<>();
+  public abstract ImmutableSet<NotifyType> getNotify();
 
-  public String getName() {
-    return name;
-  }
+  @Nullable
+  public abstract String getFilter();
 
-  public void setName(String name) {
-    this.name = name;
-  }
+  @Nullable
+  public abstract Header getHeader();
+
+  public abstract ImmutableSet<GroupReference> getGroups();
+
+  public abstract ImmutableSet<Address> getAddresses();
 
   public boolean isNotify(NotifyType type) {
-    return types.contains(type) || types.contains(NotifyType.ALL);
+    return getNotify().contains(type) || getNotify().contains(NotifyType.ALL);
   }
 
-  public Set<NotifyType> getNotify() {
-    return types;
+  public static Builder builder() {
+    return new AutoValue_NotifyConfig.Builder()
+        .setNotify(ImmutableSet.copyOf(EnumSet.of(NotifyType.ALL)));
   }
 
-  public void setTypes(Set<NotifyType> newTypes) {
-    types = EnumSet.copyOf(newTypes);
-  }
+  @AutoValue.Builder
+  public abstract static class Builder {
+    public abstract Builder setName(String name);
 
-  public String getFilter() {
-    return filter;
-  }
+    public abstract Builder setNotify(Set<NotifyType> newTypes);
 
-  public void setFilter(String filter) {
-    if ("*".equals(filter)) {
-      this.filter = null;
-    } else {
-      this.filter = Strings.emptyToNull(filter);
+    public abstract Builder setFilter(@Nullable String filter);
+
+    public abstract Builder setHeader(Header hdr);
+
+    public Builder addGroup(GroupReference group) {
+      groupsBuilder().add(group);
+      return this;
+    }
+
+    public Builder addAddress(Address address) {
+      addressesBuilder().add(address);
+      return this;
+    }
+
+    protected abstract ImmutableSet.Builder<GroupReference> groupsBuilder();
+
+    protected abstract ImmutableSet.Builder<Address> addressesBuilder();
+
+    protected abstract NotifyConfig autoBuild();
+
+    protected abstract String getFilter();
+
+    public NotifyConfig build() {
+      if ("*".equals(getFilter())) {
+        setFilter(null);
+      } else {
+        setFilter(Strings.emptyToNull(getFilter()));
+      }
+      return autoBuild();
     }
   }
 
-  public Header getHeader() {
-    return header;
-  }
-
-  public void setHeader(Header hdr) {
-    header = hdr;
-  }
-
-  public Set<GroupReference> getGroups() {
-    return groups;
-  }
-
-  public Set<Address> getAddresses() {
-    return addresses;
-  }
-
-  public void addEmail(GroupReference group) {
-    groups.add(group);
-  }
-
-  public void addEmail(Address address) {
-    addresses.add(address);
+  @Override
+  public final int compareTo(NotifyConfig o) {
+    return getName().compareTo(o.getName());
   }
 
   @Override
-  public int compareTo(NotifyConfig o) {
-    return name.compareTo(o.name);
+  public final int hashCode() {
+    return getName().hashCode();
   }
 
   @Override
-  public int hashCode() {
-    return name.hashCode();
-  }
-
-  @Override
-  public boolean equals(Object obj) {
+  public final boolean equals(Object obj) {
     if (obj instanceof NotifyConfig) {
       return compareTo((NotifyConfig) obj) == 0;
     }
     return false;
   }
-
-  @Override
-  public String toString() {
-    return MoreObjects.toStringHelper(this)
-        .add("name", name)
-        .add("addresses", addresses)
-        .add("groups", groups)
-        .add("header", header)
-        .add("types", types)
-        .add("filter", filter)
-        .toString();
-  }
 }
diff --git a/java/com/google/gerrit/server/project/LabelDefinitionJson.java b/java/com/google/gerrit/server/project/LabelDefinitionJson.java
index 0452d0b..9ff079f 100644
--- a/java/com/google/gerrit/server/project/LabelDefinitionJson.java
+++ b/java/com/google/gerrit/server/project/LabelDefinitionJson.java
@@ -31,7 +31,7 @@
         labelType.getValues().stream().collect(toMap(LabelValue::formatValue, LabelValue::getText));
     label.defaultValue = labelType.getDefaultValue();
     label.branches = labelType.getRefPatterns() != null ? labelType.getRefPatterns() : null;
-    label.canOverride = toBoolean(labelType.canOverride());
+    label.canOverride = toBoolean(labelType.isCanOverride());
     label.copyAnyScore = toBoolean(labelType.isCopyAnyScore());
     label.copyMinScore = toBoolean(labelType.isCopyMinScore());
     label.copyMaxScore = toBoolean(labelType.isCopyMaxScore());
@@ -41,8 +41,8 @@
     label.copyAllScoresOnMergeFirstParentUpdate =
         toBoolean(labelType.isCopyAllScoresOnMergeFirstParentUpdate());
     label.copyValues = labelType.getCopyValues().isEmpty() ? null : labelType.getCopyValues();
-    label.allowPostSubmit = toBoolean(labelType.allowPostSubmit());
-    label.ignoreSelfApproval = toBoolean(labelType.ignoreSelfApproval());
+    label.allowPostSubmit = toBoolean(labelType.isAllowPostSubmit());
+    label.ignoreSelfApproval = toBoolean(labelType.isIgnoreSelfApproval());
     return label;
   }
 
diff --git a/java/com/google/gerrit/server/project/ProjectConfig.java b/java/com/google/gerrit/server/project/ProjectConfig.java
index 2d4928a..35257ef 100644
--- a/java/com/google/gerrit/server/project/ProjectConfig.java
+++ b/java/com/google/gerrit/server/project/ProjectConfig.java
@@ -15,6 +15,7 @@
 package com.google.gerrit.server.project;
 
 import static com.google.common.base.Preconditions.checkArgument;
+import static com.google.common.base.Preconditions.checkState;
 import static com.google.common.collect.ImmutableList.toImmutableList;
 import static com.google.gerrit.common.data.Permission.isPermission;
 import static com.google.gerrit.entities.Project.DEFAULT_SUBMIT_TYPE;
@@ -81,6 +82,7 @@
 import java.util.Objects;
 import java.util.Optional;
 import java.util.Set;
+import java.util.function.Consumer;
 import java.util.regex.Pattern;
 import java.util.regex.PatternSyntaxException;
 import org.eclipse.jgit.errors.ConfigInvalidException;
@@ -329,6 +331,16 @@
     return project;
   }
 
+  public void setProject(Project.Builder project) {
+    this.project = project.build();
+  }
+
+  public void updateProject(Consumer<Project.Builder> update) {
+    Project.Builder builder = project.toBuilder();
+    update.accept(builder);
+    project = builder.build();
+  }
+
   public AccountsSection getAccountsSection() {
     return accountsSection;
   }
@@ -484,6 +496,20 @@
     return labelSections;
   }
 
+  /** Adds or replaces the given {@link LabelType} in this config. */
+  public void upsertLabelType(LabelType labelType) {
+    labelSections.put(labelType.getName(), labelType);
+  }
+
+  /** Allows a mutation of an existing {@link LabelType}. */
+  public void updateLabelType(String name, Consumer<LabelType.Builder> update) {
+    LabelType labelType = labelSections.get(name);
+    checkState(labelType != null, "labelType must not be null");
+    LabelType.Builder builder = labelSections.get(name).toBuilder();
+    update.accept(builder);
+    upsertLabelType(builder.build());
+  }
+
   public Collection<StoredCommentLinkInfo> getCommentLinkSections() {
     return commentLinkSections.values();
   }
@@ -579,13 +605,8 @@
 
     rulesId = getObjectId("rules.pl");
     Config rc = readConfig(PROJECT_CONFIG, baseConfig);
-    project = new Project(projectName);
-
-    Project p = project;
-    p.setDescription(rc.getString(PROJECT, null, KEY_DESCRIPTION));
-    if (p.getDescription() == null) {
-      p.setDescription("");
-    }
+    Project.Builder p = Project.builder(projectName);
+    p.setDescription(Strings.nullToEmpty(rc.getString(PROJECT, null, KEY_DESCRIPTION)));
     if (revision != null) {
       p.setConfigRefState(revision.toObjectId().name());
     }
@@ -595,7 +616,7 @@
       // as there is no guarantee which of the parents would be used then.
       error(ValidationError.create(PROJECT_CONFIG, "Cannot inherit from multiple projects"));
     }
-    p.setParentName(rc.getString(ACCESS, null, KEY_INHERIT_FROM));
+    p.setParent(rc.getString(ACCESS, null, KEY_INHERIT_FROM));
 
     for (BooleanProjectConfig config : BooleanProjectConfig.values()) {
       p.setBooleanConfig(
@@ -615,6 +636,7 @@
 
     p.setDefaultDashboard(rc.getString(DASHBOARD, null, KEY_DEFAULT));
     p.setLocalDefaultDashboard(rc.getString(DASHBOARD, null, KEY_LOCAL_DEFAULT));
+    this.project = p.build();
 
     loadAccountsSection(rc);
     loadContributorAgreements(rc);
@@ -719,13 +741,13 @@
   private void loadNotifySections(Config rc) {
     notifySections = new HashMap<>();
     for (String sectionName : rc.getSubsections(NOTIFY)) {
-      NotifyConfig n = new NotifyConfig();
+      NotifyConfig.Builder n = NotifyConfig.builder();
       n.setName(sectionName);
       n.setFilter(rc.getString(NOTIFY, sectionName, KEY_FILTER));
 
       EnumSet<NotifyType> types = EnumSet.noneOf(NotifyType.class);
       types.addAll(ConfigUtil.getEnumList(rc, NOTIFY, sectionName, KEY_TYPE, NotifyType.ALL));
-      n.setTypes(types);
+      n.setNotify(types);
       n.setHeader(rc.getEnum(NOTIFY, sectionName, KEY_HEADER, NotifyConfig.Header.BCC));
 
       for (String dst : rc.getStringList(NOTIFY, sectionName, KEY_EMAIL)) {
@@ -736,7 +758,7 @@
             ref = groupList.resolve(GroupReference.create(groupName));
           }
           if (ref.getUUID() != null) {
-            n.addEmail(ref);
+            n.addGroup(ref);
           } else {
             error(
                 ValidationError.create(
@@ -747,7 +769,7 @@
           error(ValidationError.create(PROJECT_CONFIG, dst + " not supported"));
         } else {
           try {
-            n.addEmail(Address.parse(dst));
+            n.addAddress(Address.parse(dst));
           } catch (IllegalArgumentException err) {
             error(
                 ValidationError.create(
@@ -756,7 +778,7 @@
           }
         }
       }
-      notifySections.put(sectionName, n);
+      notifySections.put(sectionName, n.build());
     }
   }
 
@@ -904,7 +926,7 @@
       throw new IllegalArgumentException("empty value");
     }
     String valueText = parts.size() > 1 ? parts.get(1) : "";
-    return new LabelValue(Shorts.checkedCast(PermissionRule.parseInt(parts.get(0))), valueText);
+    return LabelValue.create(Shorts.checkedCast(PermissionRule.parseInt(parts.get(0))), valueText);
   }
 
   private void loadLabelSections(Config rc) {
@@ -943,9 +965,9 @@
         }
       }
 
-      LabelType label;
+      LabelType.Builder label;
       try {
-        label = new LabelType(name, values);
+        label = LabelType.builder(name, values);
       } catch (IllegalArgumentException badName) {
         error(ValidationError.create(PROJECT_CONFIG, String.format("Invalid label \"%s\"", name)));
         continue;
@@ -1035,8 +1057,9 @@
       label.setCopyValues(copyValues);
       label.setCanOverride(
           rc.getBoolean(LABEL, name, KEY_CAN_OVERRIDE, LabelType.DEF_CAN_OVERRIDE));
-      label.setRefPatterns(getStringListOrNull(rc, LABEL, name, KEY_BRANCH));
-      labelSections.put(name, label);
+      List<String> refPatterns = getStringListOrNull(rc, LABEL, name, KEY_BRANCH);
+      label.setRefPatterns(refPatterns == null ? null : ImmutableList.copyOf(refPatterns));
+      labelSections.put(name, label.build());
     }
   }
 
@@ -1174,7 +1197,7 @@
         KEY_MAX_OBJECT_SIZE_LIMIT,
         validMaxObjectSizeLimit(p.getMaxObjectSizeLimit()));
 
-    set(rc, SUBMIT, null, KEY_ACTION, p.getConfiguredSubmitType(), DEFAULT_SUBMIT_TYPE);
+    set(rc, SUBMIT, null, KEY_ACTION, p.getSubmitType(), DEFAULT_SUBMIT_TYPE);
 
     set(rc, PROJECT, null, KEY_STATE, p.getState(), DEFAULT_STATE_VALUE);
 
@@ -1444,14 +1467,14 @@
           LABEL,
           name,
           KEY_ALLOW_POST_SUBMIT,
-          label.allowPostSubmit(),
+          label.isAllowPostSubmit(),
           LabelType.DEF_ALLOW_POST_SUBMIT);
       setBooleanConfigKey(
           rc,
           LABEL,
           name,
           KEY_IGNORE_SELF_APPROVAL,
-          label.ignoreSelfApproval(),
+          label.isIgnoreSelfApproval(),
           LabelType.DEF_IGNORE_SELF_APPROVAL);
       setBooleanConfigKey(
           rc,
@@ -1508,7 +1531,7 @@
           KEY_COPY_VALUE,
           label.getCopyValues().stream().map(LabelValue::formatValue).collect(toList()));
       setBooleanConfigKey(
-          rc, LABEL, name, KEY_CAN_OVERRIDE, label.canOverride(), LabelType.DEF_CAN_OVERRIDE);
+          rc, LABEL, name, KEY_CAN_OVERRIDE, label.isCanOverride(), LabelType.DEF_CAN_OVERRIDE);
       List<String> values = new ArrayList<>(label.getValues().size());
       for (LabelValue value : label.getValues()) {
         values.add(value.format().trim());
diff --git a/java/com/google/gerrit/server/project/ProjectCreator.java b/java/com/google/gerrit/server/project/ProjectCreator.java
index cc10f27..6ffbdef 100644
--- a/java/com/google/gerrit/server/project/ProjectCreator.java
+++ b/java/com/google/gerrit/server/project/ProjectCreator.java
@@ -17,6 +17,7 @@
 import static com.google.gerrit.server.project.ProjectCache.illegalState;
 
 import com.google.common.base.MoreObjects;
+import com.google.common.base.Strings;
 import com.google.common.flogger.FluentLogger;
 import com.google.gerrit.common.data.AccessSection;
 import com.google.gerrit.common.data.GroupDescription;
@@ -150,26 +151,32 @@
     try (MetaDataUpdate md = metaDataUpdateFactory.create(args.getProject())) {
       ProjectConfig config = projectConfigFactory.read(md);
 
-      Project newProject = config.getProject();
-      newProject.setDescription(args.projectDescription);
-      newProject.setSubmitType(
-          MoreObjects.firstNonNull(
-              args.submitType, repositoryCfg.getDefaultSubmitType(args.getProject())));
-      newProject.setBooleanConfig(
-          BooleanProjectConfig.USE_CONTRIBUTOR_AGREEMENTS, args.contributorAgreements);
-      newProject.setBooleanConfig(BooleanProjectConfig.USE_SIGNED_OFF_BY, args.signedOffBy);
-      newProject.setBooleanConfig(BooleanProjectConfig.USE_CONTENT_MERGE, args.contentMerge);
-      newProject.setBooleanConfig(
-          BooleanProjectConfig.CREATE_NEW_CHANGE_FOR_ALL_NOT_IN_TARGET,
-          args.newChangeForAllNotInTarget);
-      newProject.setBooleanConfig(BooleanProjectConfig.REQUIRE_CHANGE_ID, args.changeIdRequired);
-      newProject.setBooleanConfig(BooleanProjectConfig.REJECT_EMPTY_COMMIT, args.rejectEmptyCommit);
-      newProject.setMaxObjectSizeLimit(args.maxObjectSizeLimit);
-      newProject.setBooleanConfig(BooleanProjectConfig.ENABLE_SIGNED_PUSH, args.enableSignedPush);
-      newProject.setBooleanConfig(BooleanProjectConfig.REQUIRE_SIGNED_PUSH, args.requireSignedPush);
-      if (args.newParent != null) {
-        newProject.setParentName(args.newParent);
-      }
+      config.updateProject(
+          newProject -> {
+            newProject.setDescription(Strings.nullToEmpty(args.projectDescription));
+            newProject.setSubmitType(
+                MoreObjects.firstNonNull(
+                    args.submitType, repositoryCfg.getDefaultSubmitType(args.getProject())));
+            newProject.setBooleanConfig(
+                BooleanProjectConfig.USE_CONTRIBUTOR_AGREEMENTS, args.contributorAgreements);
+            newProject.setBooleanConfig(BooleanProjectConfig.USE_SIGNED_OFF_BY, args.signedOffBy);
+            newProject.setBooleanConfig(BooleanProjectConfig.USE_CONTENT_MERGE, args.contentMerge);
+            newProject.setBooleanConfig(
+                BooleanProjectConfig.CREATE_NEW_CHANGE_FOR_ALL_NOT_IN_TARGET,
+                args.newChangeForAllNotInTarget);
+            newProject.setBooleanConfig(
+                BooleanProjectConfig.REQUIRE_CHANGE_ID, args.changeIdRequired);
+            newProject.setBooleanConfig(
+                BooleanProjectConfig.REJECT_EMPTY_COMMIT, args.rejectEmptyCommit);
+            newProject.setMaxObjectSizeLimit(args.maxObjectSizeLimit);
+            newProject.setBooleanConfig(
+                BooleanProjectConfig.ENABLE_SIGNED_PUSH, args.enableSignedPush);
+            newProject.setBooleanConfig(
+                BooleanProjectConfig.REQUIRE_SIGNED_PUSH, args.requireSignedPush);
+            if (args.newParent != null) {
+              newProject.setParent(args.newParent);
+            }
+          });
 
       if (!args.ownerIds.isEmpty()) {
         AccessSection all = config.getAccessSection(AccessSection.ALL, true);
diff --git a/java/com/google/gerrit/server/project/ProjectState.java b/java/com/google/gerrit/server/project/ProjectState.java
index 1c7c7d6..6353103 100644
--- a/java/com/google/gerrit/server/project/ProjectState.java
+++ b/java/com/google/gerrit/server/project/ProjectState.java
@@ -402,7 +402,7 @@
       for (LabelType type : s.getConfig().getLabelSections().values()) {
         String lower = type.getName().toLowerCase();
         LabelType old = types.get(lower);
-        if (old == null || old.canOverride()) {
+        if (old == null || old.isCanOverride()) {
           types.put(lower, type);
         }
       }
@@ -501,7 +501,7 @@
 
   public SubmitType getSubmitType() {
     for (ProjectState s : tree()) {
-      SubmitType t = s.getProject().getConfiguredSubmitType();
+      SubmitType t = s.getProject().getSubmitType();
       if (t != SubmitType.INHERIT) {
         return t;
       }
diff --git a/java/com/google/gerrit/server/project/RefValidationHelper.java b/java/com/google/gerrit/server/project/RefValidationHelper.java
index 9b297f9..1912660 100644
--- a/java/com/google/gerrit/server/project/RefValidationHelper.java
+++ b/java/com/google/gerrit/server/project/RefValidationHelper.java
@@ -43,7 +43,7 @@
       throws ResourceConflictException {
     RefOperationValidators refValidators =
         refValidatorsFactory.create(
-            new Project(Project.nameKey(projectName)),
+            Project.builder(Project.nameKey(projectName)).build(),
             user,
             RefOperationValidators.getCommand(update, operationType));
     try {
diff --git a/java/com/google/gerrit/server/project/testing/TestLabels.java b/java/com/google/gerrit/server/project/testing/TestLabels.java
index 6c2ddde..2c0b23c 100644
--- a/java/com/google/gerrit/server/project/testing/TestLabels.java
+++ b/java/com/google/gerrit/server/project/testing/TestLabels.java
@@ -35,18 +35,23 @@
   }
 
   public static LabelType patchSetLock() {
-    LabelType label =
-        label("Patch-Set-Lock", value(1, "Patch Set Locked"), value(0, "Patch Set Unlocked"));
+    LabelType.Builder label =
+        labelBuilder(
+            "Patch-Set-Lock", value(1, "Patch Set Locked"), value(0, "Patch Set Unlocked"));
     label.setFunction(LabelFunction.PATCH_SET_LOCK);
-    return label;
+    return label.build();
   }
 
   public static LabelValue value(int value, String text) {
-    return new LabelValue((short) value, text);
+    return LabelValue.create((short) value, text);
   }
 
   public static LabelType label(String name, LabelValue... values) {
-    return new LabelType(name, Arrays.asList(values));
+    return labelBuilder(name, values).build();
+  }
+
+  public static LabelType.Builder labelBuilder(String name, LabelValue... values) {
+    return LabelType.builder(name, Arrays.asList(values));
   }
 
   private TestLabels() {}
diff --git a/java/com/google/gerrit/server/restapi/change/PostReview.java b/java/com/google/gerrit/server/restapi/change/PostReview.java
index 6edbdb0..85079e2 100644
--- a/java/com/google/gerrit/server/restapi/change/PostReview.java
+++ b/java/com/google/gerrit/server/restapi/change/PostReview.java
@@ -1319,7 +1319,7 @@
       for (PatchSetApproval psa : del) {
         LabelType lt = requireNonNull(labelTypes.byLabel(psa.label()));
         String normName = lt.getName();
-        if (!lt.allowPostSubmit()) {
+        if (!lt.isAllowPostSubmit()) {
           disallowed.add(normName);
         }
         Short prev = previous.get(normName);
@@ -1331,7 +1331,7 @@
       for (PatchSetApproval psa : ups) {
         LabelType lt = requireNonNull(labelTypes.byLabel(psa.label()));
         String normName = lt.getName();
-        if (!lt.allowPostSubmit()) {
+        if (!lt.isAllowPostSubmit()) {
           disallowed.add(normName);
         }
         Short prev = previous.get(normName);
diff --git a/java/com/google/gerrit/server/restapi/project/ConfigInfoImpl.java b/java/com/google/gerrit/server/restapi/project/ConfigInfoImpl.java
index 5deace9..783b39b 100644
--- a/java/com/google/gerrit/server/restapi/project/ConfigInfoImpl.java
+++ b/java/com/google/gerrit/server/restapi/project/ConfigInfoImpl.java
@@ -77,8 +77,7 @@
     this.defaultSubmitType.value = projectState.getSubmitType();
     this.defaultSubmitType.configuredValue =
         MoreObjects.firstNonNull(
-            projectState.getConfig().getProject().getConfiguredSubmitType(),
-            Project.DEFAULT_SUBMIT_TYPE);
+            projectState.getConfig().getProject().getSubmitType(), Project.DEFAULT_SUBMIT_TYPE);
     ProjectState parent =
         projectState.isAllProjects() ? projectState : projectState.parents().get(0);
     this.defaultSubmitType.inheritedValue = parent.getSubmitType();
diff --git a/java/com/google/gerrit/server/restapi/project/CreateLabel.java b/java/com/google/gerrit/server/restapi/project/CreateLabel.java
index a85ad39..1c19eb0 100644
--- a/java/com/google/gerrit/server/restapi/project/CreateLabel.java
+++ b/java/com/google/gerrit/server/restapi/project/CreateLabel.java
@@ -134,15 +134,15 @@
       throw new BadRequestException("values are required");
     }
 
-    List<LabelValue> values = LabelDefinitionInputParser.parseValues(input.values);
-
-    LabelType labelType;
     try {
-      labelType = new LabelType(label, values);
+      LabelType.checkName(label);
     } catch (IllegalArgumentException e) {
       throw new BadRequestException("invalid name: " + label, e);
     }
 
+    List<LabelValue> values = LabelDefinitionInputParser.parseValues(input.values);
+    LabelType.Builder labelType = LabelType.builder(LabelType.checkName(label), values);
+
     if (input.function != null && !input.function.trim().isEmpty()) {
       labelType.setFunction(LabelDefinitionInputParser.parseFunction(input.function));
     } else {
@@ -203,8 +203,9 @@
       labelType.setIgnoreSelfApproval(input.ignoreSelfApproval);
     }
 
-    config.getLabelSections().put(labelType.getName(), labelType);
+    LabelType lt = labelType.build();
+    config.upsertLabelType(lt);
 
-    return labelType;
+    return lt;
   }
 }
diff --git a/java/com/google/gerrit/server/restapi/project/LabelDefinitionInputParser.java b/java/com/google/gerrit/server/restapi/project/LabelDefinitionInputParser.java
index 1e288f4..ccc216d 100644
--- a/java/com/google/gerrit/server/restapi/project/LabelDefinitionInputParser.java
+++ b/java/com/google/gerrit/server/restapi/project/LabelDefinitionInputParser.java
@@ -14,6 +14,7 @@
 
 package com.google.gerrit.server.restapi.project;
 
+import com.google.common.collect.ImmutableList;
 import com.google.common.primitives.Shorts;
 import com.google.gerrit.common.data.LabelFunction;
 import com.google.gerrit.common.data.LabelType;
@@ -56,21 +57,22 @@
       if (valueDescription.isEmpty()) {
         throw new BadRequestException("description for value '" + e.getKey() + "' cannot be empty");
       }
-      valueList.add(new LabelValue(value, valueDescription));
+      valueList.add(LabelValue.create(value, valueDescription));
     }
     return valueList;
   }
 
-  public static short parseDefaultValue(LabelType labelType, short defaultValue)
+  public static short parseDefaultValue(LabelType.Builder labelType, short defaultValue)
       throws BadRequestException {
-    if (labelType.getValue(defaultValue) == null) {
+    if (!labelType.getValues().stream().anyMatch(v -> v.getValue() == defaultValue)) {
       throw new BadRequestException("invalid default value: " + defaultValue);
     }
     return defaultValue;
   }
 
-  public static List<String> parseBranches(List<String> branches) throws BadRequestException {
-    List<String> validBranches = new ArrayList<>();
+  public static ImmutableList<String> parseBranches(List<String> branches)
+      throws BadRequestException {
+    ImmutableList.Builder<String> validBranches = ImmutableList.builder();
     for (String branch : branches) {
       String newBranch = branch.trim();
       if (newBranch.isEmpty()) {
@@ -86,7 +88,7 @@
       }
       validBranches.add(newBranch);
     }
-    return validBranches;
+    return validBranches.build();
   }
 
   private LabelDefinitionInputParser() {}
diff --git a/java/com/google/gerrit/server/restapi/project/PutConfig.java b/java/com/google/gerrit/server/restapi/project/PutConfig.java
index 9f9433b..658f57e 100644
--- a/java/com/google/gerrit/server/restapi/project/PutConfig.java
+++ b/java/com/google/gerrit/server/restapi/project/PutConfig.java
@@ -134,28 +134,25 @@
 
     try (MetaDataUpdate md = metaDataUpdateFactory.get().create(projectName)) {
       ProjectConfig projectConfig = projectConfigFactory.read(md);
-      Project p = projectConfig.getProject();
-
-      p.setDescription(Strings.emptyToNull(input.description));
-
-      for (BooleanProjectConfig cfg : BooleanProjectConfig.values()) {
-        InheritableBoolean val = BooleanProjectConfigTransformations.get(cfg, input);
-        if (val != null) {
-          p.setBooleanConfig(cfg, val);
-        }
-      }
-
-      if (input.maxObjectSizeLimit != null) {
-        p.setMaxObjectSizeLimit(input.maxObjectSizeLimit);
-      }
-
-      if (input.submitType != null) {
-        p.setSubmitType(input.submitType);
-      }
-
-      if (input.state != null) {
-        p.setState(input.state);
-      }
+      projectConfig.updateProject(
+          p -> {
+            p.setDescription(Strings.emptyToNull(input.description));
+            for (BooleanProjectConfig cfg : BooleanProjectConfig.values()) {
+              InheritableBoolean val = BooleanProjectConfigTransformations.get(cfg, input);
+              if (val != null) {
+                p.setBooleanConfig(cfg, val);
+              }
+            }
+            if (input.maxObjectSizeLimit != null) {
+              p.setMaxObjectSizeLimit(input.maxObjectSizeLimit);
+            }
+            if (input.submitType != null) {
+              p.setSubmitType(input.submitType);
+            }
+            if (input.state != null) {
+              p.setState(input.state);
+            }
+          });
 
       if (input.pluginConfigValues != null) {
         setPluginConfigValues(projectState, projectConfig, input.pluginConfigValues);
@@ -169,7 +166,7 @@
       try {
         projectConfig.commit(md);
         projectCache.evict(projectConfig.getProject());
-        md.getRepository().setGitwebDescription(p.getDescription());
+        md.getRepository().setGitwebDescription(projectConfig.getProject().getDescription());
       } catch (IOException e) {
         if (e.getCause() instanceof ConfigInvalidException) {
           throw new ResourceConflictException(
diff --git a/java/com/google/gerrit/server/restapi/project/PutDescription.java b/java/com/google/gerrit/server/restapi/project/PutDescription.java
index a0b9feb..a65c626 100644
--- a/java/com/google/gerrit/server/restapi/project/PutDescription.java
+++ b/java/com/google/gerrit/server/restapi/project/PutDescription.java
@@ -16,7 +16,6 @@
 
 import com.google.common.base.MoreObjects;
 import com.google.common.base.Strings;
-import com.google.gerrit.entities.Project;
 import com.google.gerrit.extensions.api.projects.DescriptionInput;
 import com.google.gerrit.extensions.restapi.AuthException;
 import com.google.gerrit.extensions.restapi.ResourceConflictException;
@@ -73,8 +72,8 @@
 
     try (MetaDataUpdate md = updateFactory.get().create(resource.getNameKey())) {
       ProjectConfig config = projectConfigFactory.read(md);
-      Project project = config.getProject();
-      project.setDescription(Strings.emptyToNull(input.description));
+      String desc = input.description;
+      config.updateProject(p -> p.setDescription(Strings.emptyToNull(desc)));
 
       String msg =
           MoreObjects.firstNonNull(
@@ -86,11 +85,11 @@
       md.setMessage(msg);
       config.commit(md);
       cache.evict(resource.getProjectState().getProject());
-      md.getRepository().setGitwebDescription(project.getDescription());
+      md.getRepository().setGitwebDescription(config.getProject().getDescription());
 
-      return Strings.isNullOrEmpty(project.getDescription())
+      return Strings.isNullOrEmpty(config.getProject().getDescription())
           ? Response.none()
-          : Response.ok(project.getDescription());
+          : Response.ok(config.getProject().getDescription());
     } catch (RepositoryNotFoundException notFound) {
       throw new ResourceNotFoundException(resource.getName(), notFound);
     } catch (ConfigInvalidException e) {
diff --git a/java/com/google/gerrit/server/restapi/project/SetAccessUtil.java b/java/com/google/gerrit/server/restapi/project/SetAccessUtil.java
index 5d5e779..390dea9 100644
--- a/java/com/google/gerrit/server/restapi/project/SetAccessUtil.java
+++ b/java/com/google/gerrit/server/restapi/project/SetAccessUtil.java
@@ -243,7 +243,7 @@
       } catch (UnprocessableEntityException e) {
         throw new ResourceConflictException(e.getMessage(), e);
       }
-      config.getProject().setParentName(newParentProjectName);
+      config.updateProject(p -> p.setParent(newParentProjectName));
     }
   }
 
diff --git a/java/com/google/gerrit/server/restapi/project/SetDefaultDashboard.java b/java/com/google/gerrit/server/restapi/project/SetDefaultDashboard.java
index 9920be0..5aef76a 100644
--- a/java/com/google/gerrit/server/restapi/project/SetDefaultDashboard.java
+++ b/java/com/google/gerrit/server/restapi/project/SetDefaultDashboard.java
@@ -16,7 +16,6 @@
 
 import com.google.common.base.MoreObjects;
 import com.google.common.base.Strings;
-import com.google.gerrit.entities.Project;
 import com.google.gerrit.extensions.api.projects.DashboardInfo;
 import com.google.gerrit.extensions.api.projects.SetDashboardInput;
 import com.google.gerrit.extensions.restapi.BadRequestException;
@@ -97,11 +96,11 @@
 
     try (MetaDataUpdate md = updateFactory.create(rsrc.getProjectState().getNameKey())) {
       ProjectConfig config = projectConfigFactory.read(md);
-      Project project = config.getProject();
+      String id = input.id;
       if (inherited) {
-        project.setDefaultDashboard(input.id);
+        config.updateProject(p -> p.setDefaultDashboard(id));
       } else {
-        project.setLocalDefaultDashboard(input.id);
+        config.updateProject(p -> p.setLocalDefaultDashboard(id));
       }
 
       String msg =
diff --git a/java/com/google/gerrit/server/restapi/project/SetLabel.java b/java/com/google/gerrit/server/restapi/project/SetLabel.java
index 0a35865..ade274a 100644
--- a/java/com/google/gerrit/server/restapi/project/SetLabel.java
+++ b/java/com/google/gerrit/server/restapi/project/SetLabel.java
@@ -88,6 +88,9 @@
         } else {
           md.setMessage("Update label");
         }
+        String newName = Strings.nullToEmpty(input.name).trim();
+        labelType =
+            config.getLabelSections().get(newName.isEmpty() ? labelType.getName() : newName);
 
         config.commit(md);
         projectCache.evict(rsrc.getProject().getProjectState().getProject());
@@ -109,8 +112,7 @@
   public boolean updateLabel(ProjectConfig config, LabelType labelType, LabelDefinitionInput input)
       throws BadRequestException, ResourceConflictException {
     boolean dirty = false;
-
-    config.getLabelSections().remove(labelType.getName());
+    LabelType.Builder labelTypeBuilder = labelType.toBuilder();
 
     if (input.name != null) {
       String newName = input.name.trim();
@@ -130,10 +132,12 @@
         }
 
         try {
-          labelType.setName(newName);
+          LabelType.checkName(newName);
         } catch (IllegalArgumentException e) {
           throw new BadRequestException("invalid name: " + input.name, e);
         }
+
+        labelTypeBuilder.setName(newName);
         dirty = true;
       }
     }
@@ -142,7 +146,7 @@
       if (input.function.trim().isEmpty()) {
         throw new BadRequestException("function cannot be empty");
       }
-      labelType.setFunction(LabelDefinitionInputParser.parseFunction(input.function));
+      labelTypeBuilder.setFunction(LabelDefinitionInputParser.parseFunction(input.function));
       dirty = true;
     }
 
@@ -150,77 +154,79 @@
       if (input.values.isEmpty()) {
         throw new BadRequestException("values cannot be empty");
       }
-      labelType.setValues(LabelDefinitionInputParser.parseValues(input.values));
+      labelTypeBuilder.setValues(LabelDefinitionInputParser.parseValues(input.values));
       dirty = true;
     }
 
     if (input.defaultValue != null) {
-      labelType.setDefaultValue(
-          LabelDefinitionInputParser.parseDefaultValue(labelType, input.defaultValue));
+      labelTypeBuilder.setDefaultValue(
+          LabelDefinitionInputParser.parseDefaultValue(labelTypeBuilder, input.defaultValue));
       dirty = true;
     }
 
     if (input.branches != null) {
-      labelType.setRefPatterns(LabelDefinitionInputParser.parseBranches(input.branches));
+      labelTypeBuilder.setRefPatterns(LabelDefinitionInputParser.parseBranches(input.branches));
       dirty = true;
     }
 
     if (input.canOverride != null) {
-      labelType.setCanOverride(input.canOverride);
+      labelTypeBuilder.setCanOverride(input.canOverride);
       dirty = true;
     }
 
     if (input.copyAnyScore != null) {
-      labelType.setCopyAnyScore(input.copyAnyScore);
+      labelTypeBuilder.setCopyAnyScore(input.copyAnyScore);
       dirty = true;
     }
 
     if (input.copyMinScore != null) {
-      labelType.setCopyMinScore(input.copyMinScore);
+      labelTypeBuilder.setCopyMinScore(input.copyMinScore);
       dirty = true;
     }
 
     if (input.copyMaxScore != null) {
-      labelType.setCopyMaxScore(input.copyMaxScore);
+      labelTypeBuilder.setCopyMaxScore(input.copyMaxScore);
       dirty = true;
     }
 
     if (input.copyAllScoresIfNoChange != null) {
-      labelType.setCopyAllScoresIfNoChange(input.copyAllScoresIfNoChange);
+      labelTypeBuilder.setCopyAllScoresIfNoChange(input.copyAllScoresIfNoChange);
+      dirty = true;
     }
 
     if (input.copyAllScoresIfNoCodeChange != null) {
-      labelType.setCopyAllScoresIfNoCodeChange(input.copyAllScoresIfNoCodeChange);
+      labelTypeBuilder.setCopyAllScoresIfNoCodeChange(input.copyAllScoresIfNoCodeChange);
       dirty = true;
     }
 
     if (input.copyAllScoresOnTrivialRebase != null) {
-      labelType.setCopyAllScoresOnTrivialRebase(input.copyAllScoresOnTrivialRebase);
+      labelTypeBuilder.setCopyAllScoresOnTrivialRebase(input.copyAllScoresOnTrivialRebase);
       dirty = true;
     }
 
     if (input.copyAllScoresOnMergeFirstParentUpdate != null) {
-      labelType.setCopyAllScoresOnMergeFirstParentUpdate(
+      labelTypeBuilder.setCopyAllScoresOnMergeFirstParentUpdate(
           input.copyAllScoresOnMergeFirstParentUpdate);
       dirty = true;
     }
 
     if (input.copyValues != null) {
-      labelType.setCopyValues(input.copyValues);
+      labelTypeBuilder.setCopyValues(input.copyValues);
       dirty = true;
     }
 
     if (input.allowPostSubmit != null) {
-      labelType.setAllowPostSubmit(input.allowPostSubmit);
+      labelTypeBuilder.setAllowPostSubmit(input.allowPostSubmit);
       dirty = true;
     }
 
     if (input.ignoreSelfApproval != null) {
-      labelType.setIgnoreSelfApproval(input.ignoreSelfApproval);
+      labelTypeBuilder.setIgnoreSelfApproval(input.ignoreSelfApproval);
       dirty = true;
     }
 
-    config.getLabelSections().put(labelType.getName(), labelType);
+    config.getLabelSections().remove(labelType.getName());
+    config.upsertLabelType(labelTypeBuilder.build());
 
     return dirty;
   }
diff --git a/java/com/google/gerrit/server/restapi/project/SetParent.java b/java/com/google/gerrit/server/restapi/project/SetParent.java
index 42790aa..91c29f5 100644
--- a/java/com/google/gerrit/server/restapi/project/SetParent.java
+++ b/java/com/google/gerrit/server/restapi/project/SetParent.java
@@ -103,8 +103,7 @@
     validateParentUpdate(rsrc.getProjectState().getNameKey(), user, parentName, checkIfAdmin);
     try (MetaDataUpdate md = updateFactory.get().create(rsrc.getNameKey())) {
       ProjectConfig config = projectConfigFactory.read(md);
-      Project project = config.getProject();
-      project.setParentName(parentName);
+      config.updateProject(p -> p.setParent(parentName));
 
       String msg = Strings.emptyToNull(input.commitMessage);
       if (msg == null) {
@@ -117,7 +116,7 @@
       config.commit(md);
       cache.evict(rsrc.getProjectState().getProject());
 
-      Project.NameKey parent = project.getParent(allProjects);
+      Project.NameKey parent = config.getProject().getParent(allProjects);
       requireNonNull(parent);
       return parent.get();
     } catch (RepositoryNotFoundException notFound) {
diff --git a/java/com/google/gerrit/server/rules/IgnoreSelfApprovalRule.java b/java/com/google/gerrit/server/rules/IgnoreSelfApprovalRule.java
index 54915fb..132747d 100644
--- a/java/com/google/gerrit/server/rules/IgnoreSelfApprovalRule.java
+++ b/java/com/google/gerrit/server/rules/IgnoreSelfApprovalRule.java
@@ -66,7 +66,8 @@
       return ruleError(E_UNABLE_TO_FETCH_LABELS);
     }
 
-    boolean shouldIgnoreSelfApproval = labelTypes.stream().anyMatch(LabelType::ignoreSelfApproval);
+    boolean shouldIgnoreSelfApproval =
+        labelTypes.stream().anyMatch(LabelType::isIgnoreSelfApproval);
     if (!shouldIgnoreSelfApproval) {
       // Shortcut to avoid further processing if no label should ignore uploader approvals
       return Optional.empty();
@@ -86,7 +87,7 @@
     submitRecord.requirements = new ArrayList<>();
 
     for (LabelType t : labelTypes) {
-      if (!t.ignoreSelfApproval()) {
+      if (!t.isIgnoreSelfApproval()) {
         // The default rules are enough in this case.
         continue;
       }
diff --git a/java/com/google/gerrit/server/schema/AllProjectsCreator.java b/java/com/google/gerrit/server/schema/AllProjectsCreator.java
index cfa5825..018a96a 100644
--- a/java/com/google/gerrit/server/schema/AllProjectsCreator.java
+++ b/java/com/google/gerrit/server/schema/AllProjectsCreator.java
@@ -30,7 +30,6 @@
 import com.google.gerrit.common.data.Permission;
 import com.google.gerrit.common.data.PermissionRule;
 import com.google.gerrit.common.data.PermissionRule.Action;
-import com.google.gerrit.entities.Project;
 import com.google.gerrit.entities.RefNames;
 import com.google.gerrit.server.GerritPersonIdent;
 import com.google.gerrit.server.config.AllProjectsName;
@@ -116,19 +115,16 @@
 
       // init basic project configs.
       ProjectConfig config = projectConfigFactory.read(md);
-      Project p = config.getProject();
-      p.setDescription(
-          input.projectDescription().orElse("Access inherited by all other projects."));
-
-      // init boolean project configs.
-      input.booleanProjectConfigs().forEach(p::setBooleanConfig);
+      config.updateProject(
+          p -> {
+            p.setDescription(
+                input.projectDescription().orElse("Access inherited by all other projects."));
+            // init boolean project configs.
+            input.booleanProjectConfigs().forEach(p::setBooleanConfig);
+          });
 
       // init labels.
-      input
-          .codeReviewLabel()
-          .ifPresent(
-              codeReviewLabel ->
-                  config.getLabelSections().put(codeReviewLabel.getName(), codeReviewLabel));
+      input.codeReviewLabel().ifPresent(codeReviewLabel -> config.upsertLabelType(codeReviewLabel));
 
       if (input.initDefaultAcls()) {
         // init access sections.
diff --git a/java/com/google/gerrit/server/schema/AllProjectsInput.java b/java/com/google/gerrit/server/schema/AllProjectsInput.java
index 6e11a5d..c91695f 100644
--- a/java/com/google/gerrit/server/schema/AllProjectsInput.java
+++ b/java/com/google/gerrit/server/schema/AllProjectsInput.java
@@ -46,18 +46,17 @@
 
   @UsedAt(UsedAt.Project.GOOGLE)
   public static LabelType getDefaultCodeReviewLabel() {
-    LabelType type =
-        new LabelType(
+    return LabelType.builder(
             "Code-Review",
             ImmutableList.of(
-                new LabelValue((short) 2, "Looks good to me, approved"),
-                new LabelValue((short) 1, "Looks good to me, but someone else must approve"),
-                new LabelValue((short) 0, "No score"),
-                new LabelValue((short) -1, "I would prefer this is not merged as is"),
-                new LabelValue((short) -2, "This shall not be merged")));
-    type.setCopyMinScore(true);
-    type.setCopyAllScoresOnTrivialRebase(true);
-    return type;
+                LabelValue.create((short) 2, "Looks good to me, approved"),
+                LabelValue.create((short) 1, "Looks good to me, but someone else must approve"),
+                LabelValue.create((short) 0, "No score"),
+                LabelValue.create((short) -1, "I would prefer this is not merged as is"),
+                LabelValue.create((short) -2, "This shall not be merged")))
+        .setCopyMinScore(true)
+        .setCopyAllScoresOnTrivialRebase(true)
+        .build();
   }
 
   /** The administrator group which gets default permissions granted. */
diff --git a/java/com/google/gerrit/server/schema/AllUsersCreator.java b/java/com/google/gerrit/server/schema/AllUsersCreator.java
index 4904028..10d7070 100644
--- a/java/com/google/gerrit/server/schema/AllUsersCreator.java
+++ b/java/com/google/gerrit/server/schema/AllUsersCreator.java
@@ -26,7 +26,6 @@
 import com.google.gerrit.common.data.GroupReference;
 import com.google.gerrit.common.data.LabelType;
 import com.google.gerrit.common.data.Permission;
-import com.google.gerrit.entities.Project;
 import com.google.gerrit.entities.RefNames;
 import com.google.gerrit.server.GerritPersonIdent;
 import com.google.gerrit.server.config.AllUsersName;
@@ -112,15 +111,14 @@
       md.setMessage("Initialized Gerrit Code Review " + Version.getVersion());
 
       ProjectConfig config = projectConfigFactory.read(md);
-      Project project = config.getProject();
-      project.setDescription("Individual user settings and preferences.");
+      config.updateProject(p -> p.setDescription("Individual user settings and preferences."));
 
       AccessSection users =
           config.getAccessSection(
               RefNames.REFS_USERS + "${" + RefPattern.USERID_SHARDED + "}", true);
 
       // Initialize "Code-Review" label.
-      config.getLabelSections().put(codeReviewLabel.getName(), codeReviewLabel);
+      config.upsertLabelType(codeReviewLabel);
 
       grant(config, users, Permission.READ, false, true, registered);
       grant(config, users, Permission.PUSH, false, true, registered);
diff --git a/javatests/com/google/gerrit/acceptance/api/accounts/AgreementsIT.java b/javatests/com/google/gerrit/acceptance/api/accounts/AgreementsIT.java
index 11cc82f..c0a9da6 100644
--- a/javatests/com/google/gerrit/acceptance/api/accounts/AgreementsIT.java
+++ b/javatests/com/google/gerrit/acceptance/api/accounts/AgreementsIT.java
@@ -67,7 +67,8 @@
   protected void setUseContributorAgreements(InheritableBoolean value) throws Exception {
     try (MetaDataUpdate md = metaDataUpdateFactory.create(project)) {
       ProjectConfig config = projectConfigFactory.read(md);
-      config.getProject().setBooleanConfig(BooleanProjectConfig.USE_CONTRIBUTOR_AGREEMENTS, value);
+      config.updateProject(
+          p -> p.setBooleanConfig(BooleanProjectConfig.USE_CONTRIBUTOR_AGREEMENTS, value));
       config.commit(md);
       projectCache.evict(config.getProject());
     }
diff --git a/javatests/com/google/gerrit/acceptance/api/change/ChangeIT.java b/javatests/com/google/gerrit/acceptance/api/change/ChangeIT.java
index 39a860e..42c09c7 100644
--- a/javatests/com/google/gerrit/acceptance/api/change/ChangeIT.java
+++ b/javatests/com/google/gerrit/acceptance/api/change/ChangeIT.java
@@ -2231,7 +2231,7 @@
     LabelType verified =
         label("Verified", value(1, "Passes"), value(0, "No score"), value(-1, "Failed"));
     try (ProjectConfigUpdate u = updateProject(project)) {
-      u.getConfig().getLabelSections().put(verified.getName(), verified);
+      u.getConfig().upsertLabelType(verified);
       u.save();
     }
     projectOperations
@@ -2518,7 +2518,7 @@
         label("Verified", value(1, "Passes"), value(0, "No score"), value(-1, "Failed"));
     String heads = "refs/heads/*";
     try (ProjectConfigUpdate u = updateProject(project)) {
-      u.getConfig().getLabelSections().put(verified.getName(), verified);
+      u.getConfig().upsertLabelType(verified);
       u.save();
     }
     projectOperations
@@ -2863,9 +2863,9 @@
     LabelType custom2 =
         label("Custom2", value(1, "Positive"), value(0, "No score"), value(-1, "Negative"));
     try (ProjectConfigUpdate u = updateProject(project)) {
-      u.getConfig().getLabelSections().put(verified.getName(), verified);
-      u.getConfig().getLabelSections().put(custom1.getName(), custom1);
-      u.getConfig().getLabelSections().put(custom2.getName(), custom2);
+      u.getConfig().upsertLabelType(verified);
+      u.getConfig().upsertLabelType(custom1);
+      u.getConfig().upsertLabelType(custom2);
       u.save();
     }
     projectOperations
@@ -3603,7 +3603,7 @@
     String heads = RefNames.REFS_HEADS + "*";
 
     try (ProjectConfigUpdate u = updateProject(project)) {
-      u.getConfig().getLabelSections().put(verified.getName(), verified);
+      u.getConfig().upsertLabelType(verified);
       u.save();
     }
     projectOperations
@@ -3671,7 +3671,7 @@
 
     // add new label and assert that it's returned for existing changes
     try (ProjectConfigUpdate u = updateProject(project)) {
-      u.getConfig().getLabelSections().put(verified.getName(), verified);
+      u.getConfig().upsertLabelType(verified);
       u.save();
     }
     projectOperations
diff --git a/javatests/com/google/gerrit/acceptance/api/change/RevertIT.java b/javatests/com/google/gerrit/acceptance/api/change/RevertIT.java
index 0ac7e20..b855e72 100644
--- a/javatests/com/google/gerrit/acceptance/api/change/RevertIT.java
+++ b/javatests/com/google/gerrit/acceptance/api/change/RevertIT.java
@@ -398,7 +398,7 @@
         .review(ReviewInput.approve());
     gApi.changes().id(result.getChangeId()).revision(result.getCommit().name()).submit();
     try (ProjectConfigUpdate u = updateProject(project)) {
-      u.getConfig().getProject().setState(ProjectState.READ_ONLY);
+      u.getConfig().updateProject(p -> p.setState(ProjectState.READ_ONLY));
       u.save();
     }
 
@@ -481,7 +481,7 @@
 
     // revoke write permissions for the first repository.
     try (ProjectConfigUpdate u = updateProject(project)) {
-      u.getConfig().getProject().setState(ProjectState.READ_ONLY);
+      u.getConfig().updateProject(p -> p.setState(ProjectState.READ_ONLY));
       u.save();
     }
 
diff --git a/javatests/com/google/gerrit/acceptance/api/change/StickyApprovalsIT.java b/javatests/com/google/gerrit/acceptance/api/change/StickyApprovalsIT.java
index 923b66f..3d8a034 100644
--- a/javatests/com/google/gerrit/acceptance/api/change/StickyApprovalsIT.java
+++ b/javatests/com/google/gerrit/acceptance/api/change/StickyApprovalsIT.java
@@ -26,7 +26,7 @@
 import static com.google.gerrit.extensions.client.ListChangesOption.CURRENT_REVISION;
 import static com.google.gerrit.extensions.client.ListChangesOption.DETAILED_LABELS;
 import static com.google.gerrit.server.group.SystemGroupBackend.REGISTERED_USERS;
-import static com.google.gerrit.server.project.testing.TestLabels.label;
+import static com.google.gerrit.server.project.testing.TestLabels.labelBuilder;
 import static com.google.gerrit.server.project.testing.TestLabels.value;
 import static org.eclipse.jgit.lib.Constants.HEAD;
 
@@ -78,8 +78,8 @@
     try (ProjectConfigUpdate u = updateProject(project)) {
       // Overwrite "Code-Review" label that is inherited from All-Projects.
       // This way changes to the "Code Review" label don't affect other tests.
-      LabelType codeReview =
-          label(
+      LabelType.Builder codeReview =
+          labelBuilder(
               "Code-Review",
               value(2, "Looks good to me, approved"),
               value(1, "Looks good to me, but someone else must approve"),
@@ -87,12 +87,12 @@
               value(-1, "I would prefer that you didn't submit this"),
               value(-2, "Do not submit"));
       codeReview.setCopyAllScoresIfNoChange(false);
-      u.getConfig().getLabelSections().put(codeReview.getName(), codeReview);
+      u.getConfig().upsertLabelType(codeReview.build());
 
-      LabelType verified =
-          label("Verified", value(1, "Passes"), value(0, "No score"), value(-1, "Failed"));
+      LabelType.Builder verified =
+          labelBuilder("Verified", value(1, "Passes"), value(0, "No score"), value(-1, "Failed"));
       verified.setCopyAllScoresIfNoChange(false);
-      u.getConfig().getLabelSections().put(verified.getName(), verified);
+      u.getConfig().upsertLabelType(verified.build());
 
       u.save();
     }
@@ -121,7 +121,7 @@
   @Test
   public void stickyOnAnyScore() throws Exception {
     try (ProjectConfigUpdate u = updateProject(project)) {
-      u.getConfig().getLabelSections().get("Code-Review").setCopyAnyScore(true);
+      u.getConfig().updateLabelType("Code-Review", b -> b.setCopyAnyScore(true));
       u.save();
     }
 
@@ -143,7 +143,7 @@
   @Test
   public void stickyOnMinScore() throws Exception {
     try (ProjectConfigUpdate u = updateProject(project)) {
-      u.getConfig().getLabelSections().get("Code-Review").setCopyMinScore(true);
+      u.getConfig().updateLabelType("Code-Review", b -> b.setCopyMinScore(true));
       u.save();
     }
 
@@ -165,7 +165,7 @@
   @Test
   public void stickyOnMaxScore() throws Exception {
     try (ProjectConfigUpdate u = updateProject(project)) {
-      u.getConfig().getLabelSections().get("Code-Review").setCopyMaxScore(true);
+      u.getConfig().updateLabelType("Code-Review", b -> b.setCopyMaxScore(true));
       u.save();
     }
 
@@ -190,9 +190,8 @@
 
     try (ProjectConfigUpdate u = updateProject(project)) {
       u.getConfig()
-          .getLabelSections()
-          .get("Code-Review")
-          .setCopyValues(ImmutableList.of((short) -1, (short) 1));
+          .updateLabelType(
+              "Code-Review", b -> b.setCopyValues(ImmutableList.of((short) -1, (short) 1)));
       u.save();
     }
 
@@ -216,7 +215,7 @@
   @Test
   public void stickyOnTrivialRebase() throws Exception {
     try (ProjectConfigUpdate u = updateProject(project)) {
-      u.getConfig().getLabelSections().get("Code-Review").setCopyAllScoresOnTrivialRebase(true);
+      u.getConfig().updateLabelType("Code-Review", b -> b.setCopyAllScoresOnTrivialRebase(true));
       u.save();
     }
 
@@ -262,7 +261,7 @@
   @Test
   public void stickyOnNoCodeChange() throws Exception {
     try (ProjectConfigUpdate u = updateProject(project)) {
-      u.getConfig().getLabelSections().get("Verified").setCopyAllScoresIfNoCodeChange(true);
+      u.getConfig().updateLabelType("Verified", b -> b.setCopyAllScoresIfNoCodeChange(true));
       u.save();
     }
 
@@ -287,9 +286,7 @@
   public void stickyOnMergeFirstParentUpdate() throws Exception {
     try (ProjectConfigUpdate u = updateProject(project)) {
       u.getConfig()
-          .getLabelSections()
-          .get("Code-Review")
-          .setCopyAllScoresOnMergeFirstParentUpdate(true);
+          .updateLabelType("Code-Review", b -> b.setCopyAllScoresOnMergeFirstParentUpdate(true));
       u.save();
     }
 
@@ -313,7 +310,7 @@
   @Test
   public void notStickyWithCopyOnNoChangeWhenSecondParentIsUpdated() throws Exception {
     try (ProjectConfigUpdate u = updateProject(project)) {
-      u.getConfig().getLabelSections().get("Code-Review").setCopyAllScoresIfNoChange(true);
+      u.getConfig().updateLabelType("Code-Review", b -> b.setCopyAllScoresIfNoChange(true));
       u.save();
     }
 
@@ -330,8 +327,8 @@
   @Test
   public void removedVotesNotSticky() throws Exception {
     try (ProjectConfigUpdate u = updateProject(project)) {
-      u.getConfig().getLabelSections().get("Code-Review").setCopyAllScoresOnTrivialRebase(true);
-      u.getConfig().getLabelSections().get("Verified").setCopyAllScoresIfNoCodeChange(true);
+      u.getConfig().updateLabelType("Code-Review", b -> b.setCopyAllScoresOnTrivialRebase(true));
+      u.getConfig().updateLabelType("Verified", b -> b.setCopyAllScoresIfNoCodeChange(true));
       u.save();
     }
 
@@ -360,8 +357,8 @@
   @Test
   public void stickyAcrossMultiplePatchSets() throws Exception {
     try (ProjectConfigUpdate u = updateProject(project)) {
-      u.getConfig().getLabelSections().get("Code-Review").setCopyMaxScore(true);
-      u.getConfig().getLabelSections().get("Verified").setCopyAllScoresIfNoCodeChange(true);
+      u.getConfig().updateLabelType("Code-Review", b -> b.setCopyMaxScore(true));
+      u.getConfig().updateLabelType("Verified", b -> b.setCopyAllScoresIfNoCodeChange(true));
       u.save();
     }
 
@@ -386,8 +383,8 @@
     // change kind against all prior patch sets. This is a regression that made Gerrit do expensive
     // work in O(num-patch-sets). This test ensures that we aren't regressing.
     try (ProjectConfigUpdate u = updateProject(project)) {
-      u.getConfig().getLabelSections().get("Code-Review").setCopyMaxScore(true);
-      u.getConfig().getLabelSections().get("Verified").setCopyAllScoresIfNoCodeChange(true);
+      u.getConfig().updateLabelType("Code-Review", b -> b.setCopyMaxScore(true));
+      u.getConfig().updateLabelType("Verified", b -> b.setCopyAllScoresIfNoCodeChange(true));
       u.save();
     }
 
@@ -418,8 +415,8 @@
   @Test
   public void copyMinMaxAcrossMultiplePatchSets() throws Exception {
     try (ProjectConfigUpdate u = updateProject(project)) {
-      u.getConfig().getLabelSections().get("Code-Review").setCopyMaxScore(true);
-      u.getConfig().getLabelSections().get("Code-Review").setCopyMinScore(true);
+      u.getConfig().updateLabelType("Code-Review", b -> b.setCopyMaxScore(true));
+      u.getConfig().updateLabelType("Code-Review", b -> b.setCopyMinScore(true));
       u.save();
     }
 
@@ -459,7 +456,7 @@
   public void deleteStickyVote() throws Exception {
     String label = "Code-Review";
     try (ProjectConfigUpdate u = updateProject(project)) {
-      u.getConfig().getLabelSections().get(label).setCopyMaxScore(true);
+      u.getConfig().updateLabelType(label, b -> b.setCopyMaxScore(true));
       u.save();
     }
 
diff --git a/javatests/com/google/gerrit/acceptance/api/project/ProjectIndexerIT.java b/javatests/com/google/gerrit/acceptance/api/project/ProjectIndexerIT.java
index dad09f9..e45d95c 100644
--- a/javatests/com/google/gerrit/acceptance/api/project/ProjectIndexerIT.java
+++ b/javatests/com/google/gerrit/acceptance/api/project/ProjectIndexerIT.java
@@ -104,18 +104,18 @@
     Project.NameKey p1 = projectOperations.newProject().create();
     Project.NameKey p2 = projectOperations.newProject().create();
     try (ProjectConfigUpdate u = updateProject(project)) {
-      u.getConfig().getProject().setParentName(p1);
+      u.getConfig().updateProject(p -> p.setParent(p1));
       u.save();
     }
     assertThat(stalenessChecker.check(project).isStale()).isFalse();
 
-    updateProjectConfigWithoutIndexUpdate(p1, c -> c.getProject().setParentName(p2));
+    updateProjectConfigWithoutIndexUpdate(p1, c -> c.updateProject(p -> p.setParent(p2)));
     assertThat(stalenessChecker.check(project).isStale()).isTrue();
   }
 
   private void updateProjectConfigWithoutIndexUpdate(Project.NameKey project) throws Exception {
     updateProjectConfigWithoutIndexUpdate(
-        project, c -> c.getProject().setDescription("making it stale"));
+        project, c -> c.updateProject(p -> p.setDescription("making it stale")));
   }
 
   private void updateProjectConfigWithoutIndexUpdate(
diff --git a/javatests/com/google/gerrit/acceptance/edit/ChangeEditIT.java b/javatests/com/google/gerrit/acceptance/edit/ChangeEditIT.java
index f0bb201..d361247 100644
--- a/javatests/com/google/gerrit/acceptance/edit/ChangeEditIT.java
+++ b/javatests/com/google/gerrit/acceptance/edit/ChangeEditIT.java
@@ -772,8 +772,9 @@
     String cr = "Code-Review";
     try (ProjectConfigUpdate u = updateProject(project)) {
       LabelType codeReview = TestLabels.codeReview();
-      codeReview.setCopyAllScoresIfNoCodeChange(true);
-      u.getConfig().getLabelSections().put(cr, codeReview);
+      u.getConfig().upsertLabelType(codeReview);
+      u.getConfig()
+          .updateLabelType(codeReview.getName(), lt -> lt.setCopyAllScoresIfNoCodeChange(true));
       u.save();
     }
 
diff --git a/javatests/com/google/gerrit/acceptance/git/AbstractPushForReview.java b/javatests/com/google/gerrit/acceptance/git/AbstractPushForReview.java
index 7213a9f..b01b195 100644
--- a/javatests/com/google/gerrit/acceptance/git/AbstractPushForReview.java
+++ b/javatests/com/google/gerrit/acceptance/git/AbstractPushForReview.java
@@ -161,7 +161,7 @@
   public void setUpPatchSetLock() throws Exception {
     try (ProjectConfigUpdate u = updateProject(project)) {
       patchSetLock = TestLabels.patchSetLock();
-      u.getConfig().getLabelSections().put(patchSetLock.getName(), patchSetLock);
+      u.getConfig().upsertLabelType(patchSetLock);
       u.save();
     }
     projectOperations
@@ -1200,7 +1200,7 @@
         label("Custom-Label", value(1, "Positive"), value(0, "No score"), value(-1, "Negative"));
     String heads = "refs/heads/*";
     try (ProjectConfigUpdate u = updateProject(project)) {
-      u.getConfig().getLabelSections().put(Q.getName(), Q);
+      u.getConfig().upsertLabelType(Q);
       u.save();
     }
     projectOperations
@@ -1686,8 +1686,10 @@
 
     try (ProjectConfigUpdate u = updateProject(project)) {
       u.getConfig()
-          .getProject()
-          .setBooleanConfig(BooleanProjectConfig.REQUIRE_CHANGE_ID, InheritableBoolean.FALSE);
+          .updateProject(
+              p ->
+                  p.setBooleanConfig(
+                      BooleanProjectConfig.REQUIRE_CHANGE_ID, InheritableBoolean.FALSE));
       u.save();
     }
 
@@ -1712,8 +1714,10 @@
 
     try (ProjectConfigUpdate u = updateProject(project)) {
       u.getConfig()
-          .getProject()
-          .setBooleanConfig(BooleanProjectConfig.REQUIRE_CHANGE_ID, InheritableBoolean.FALSE);
+          .updateProject(
+              p ->
+                  p.setBooleanConfig(
+                      BooleanProjectConfig.REQUIRE_CHANGE_ID, InheritableBoolean.FALSE));
       u.save();
     }
 
@@ -1863,9 +1867,8 @@
   @Test
   public void pushNewPatchsetOverridingStickyLabel() throws Exception {
     try (ProjectConfigUpdate u = updateProject(project)) {
-      LabelType codeReview = TestLabels.codeReview();
-      codeReview.setCopyMaxScore(true);
-      u.getConfig().getLabelSections().put(codeReview.getName(), codeReview);
+      LabelType codeReview = TestLabels.codeReview().toBuilder().setCopyMaxScore(true).build();
+      u.getConfig().upsertLabelType(codeReview);
       u.save();
     }
 
diff --git a/javatests/com/google/gerrit/acceptance/git/ImplicitMergeCheckIT.java b/javatests/com/google/gerrit/acceptance/git/ImplicitMergeCheckIT.java
index b51263e..80cc508 100644
--- a/javatests/com/google/gerrit/acceptance/git/ImplicitMergeCheckIT.java
+++ b/javatests/com/google/gerrit/acceptance/git/ImplicitMergeCheckIT.java
@@ -85,8 +85,10 @@
   private void setRejectImplicitMerges() throws Exception {
     try (ProjectConfigUpdate u = updateProject(project)) {
       u.getConfig()
-          .getProject()
-          .setBooleanConfig(BooleanProjectConfig.REJECT_IMPLICIT_MERGES, InheritableBoolean.TRUE);
+          .updateProject(
+              p ->
+                  p.setBooleanConfig(
+                      BooleanProjectConfig.REJECT_IMPLICIT_MERGES, InheritableBoolean.TRUE));
       u.save();
     }
   }
diff --git a/javatests/com/google/gerrit/acceptance/git/PushPermissionsIT.java b/javatests/com/google/gerrit/acceptance/git/PushPermissionsIT.java
index f9c751f..98b93a8 100644
--- a/javatests/com/google/gerrit/acceptance/git/PushPermissionsIT.java
+++ b/javatests/com/google/gerrit/acceptance/git/PushPermissionsIT.java
@@ -175,7 +175,7 @@
   public void readOnlyProjectRejectedBeforeTestingPermissions() throws Exception {
     try (Repository repo = repoManager.openRepository(project)) {
       try (ProjectConfigUpdate u = updateProject(project)) {
-        u.getConfig().getProject().setState(ProjectState.READ_ONLY);
+        u.getConfig().updateProject(p -> p.setState(ProjectState.READ_ONLY));
         u.save();
       }
     }
diff --git a/javatests/com/google/gerrit/acceptance/rest/account/ImpersonationIT.java b/javatests/com/google/gerrit/acceptance/rest/account/ImpersonationIT.java
index 840853c..00c7fb8 100644
--- a/javatests/com/google/gerrit/acceptance/rest/account/ImpersonationIT.java
+++ b/javatests/com/google/gerrit/acceptance/rest/account/ImpersonationIT.java
@@ -174,7 +174,7 @@
   public void voteOnBehalfOfLabelNotPermitted() throws Exception {
     try (ProjectConfigUpdate u = updateProject(project)) {
       LabelType verified = TestLabels.verified();
-      u.getConfig().getLabelSections().put(verified.getName(), verified);
+      u.getConfig().upsertLabelType(verified);
       u.save();
     }
 
diff --git a/javatests/com/google/gerrit/acceptance/rest/binding/ProjectsRestApiBindingsIT.java b/javatests/com/google/gerrit/acceptance/rest/binding/ProjectsRestApiBindingsIT.java
index 55eeaf4..1027938 100644
--- a/javatests/com/google/gerrit/acceptance/rest/binding/ProjectsRestApiBindingsIT.java
+++ b/javatests/com/google/gerrit/acceptance/rest/binding/ProjectsRestApiBindingsIT.java
@@ -277,7 +277,7 @@
     }
 
     try (ProjectConfigUpdate u = updateProject(project)) {
-      u.getConfig().getProject().setLocalDefaultDashboard(dashboardRef + ":overview");
+      u.getConfig().updateProject(p -> p.setLocalDefaultDashboard(dashboardRef + ":overview"));
       u.save();
     }
   }
diff --git a/javatests/com/google/gerrit/acceptance/rest/change/MoveChangeIT.java b/javatests/com/google/gerrit/acceptance/rest/change/MoveChangeIT.java
index 37b1713..542085c 100644
--- a/javatests/com/google/gerrit/acceptance/rest/change/MoveChangeIT.java
+++ b/javatests/com/google/gerrit/acceptance/rest/change/MoveChangeIT.java
@@ -245,7 +245,7 @@
 
     LabelType patchSetLock = TestLabels.patchSetLock();
     try (ProjectConfigUpdate u = updateProject(project)) {
-      u.getConfig().getLabelSections().put(patchSetLock.getName(), patchSetLock);
+      u.getConfig().upsertLabelType(patchSetLock);
       u.save();
     }
     projectOperations
diff --git a/javatests/com/google/gerrit/acceptance/rest/project/CreateProjectIT.java b/javatests/com/google/gerrit/acceptance/rest/project/CreateProjectIT.java
index 874f07a..10fd65f 100644
--- a/javatests/com/google/gerrit/acceptance/rest/project/CreateProjectIT.java
+++ b/javatests/com/google/gerrit/acceptance/rest/project/CreateProjectIT.java
@@ -224,7 +224,7 @@
     Project project = projectCache.get(Project.nameKey(newProjectName)).get().getProject();
     assertProjectInfo(project, p);
     assertThat(project.getDescription()).isEqualTo(in.description);
-    assertThat(project.getConfiguredSubmitType()).isEqualTo(in.submitType);
+    assertThat(project.getSubmitType()).isEqualTo(in.submitType);
     assertThat(project.getBooleanConfig(BooleanProjectConfig.USE_CONTRIBUTOR_AGREEMENTS))
         .isEqualTo(in.useContributorAgreements);
     assertThat(project.getBooleanConfig(BooleanProjectConfig.USE_SIGNED_OFF_BY))
@@ -368,8 +368,11 @@
 
   @Test
   public void createProjectWithCreateProjectCapabilityAndParentNotVisible() throws Exception {
-    Project parent = projectCache.get(allProjects).get().getProject();
-    parent.setState(com.google.gerrit.extensions.client.ProjectState.HIDDEN);
+    try (ProjectConfigUpdate u = updateProject(allProjects)) {
+      u.getConfig()
+          .updateProject(p -> p.setState(com.google.gerrit.extensions.client.ProjectState.HIDDEN));
+      u.save();
+    }
     projectOperations
         .allProjectsForUpdate()
         .add(
@@ -383,7 +386,12 @@
       ProjectInfo p = gApi.projects().create(in).get();
       assertThat(p.name).isEqualTo(in.name);
     } finally {
-      parent.setState(com.google.gerrit.extensions.client.ProjectState.ACTIVE);
+      try (ProjectConfigUpdate u = updateProject(allProjects)) {
+        u.getConfig()
+            .updateProject(
+                p -> p.setState(com.google.gerrit.extensions.client.ProjectState.ACTIVE));
+        u.save();
+      }
       projectOperations
           .allProjectsForUpdate()
           .remove(
diff --git a/javatests/com/google/gerrit/acceptance/rest/project/GetLabelIT.java b/javatests/com/google/gerrit/acceptance/rest/project/GetLabelIT.java
index 940fae5..3e35f04 100644
--- a/javatests/com/google/gerrit/acceptance/rest/project/GetLabelIT.java
+++ b/javatests/com/google/gerrit/acceptance/rest/project/GetLabelIT.java
@@ -22,7 +22,6 @@
 import com.google.gerrit.acceptance.NoHttpd;
 import com.google.gerrit.acceptance.testsuite.request.RequestScopeOperations;
 import com.google.gerrit.common.data.LabelFunction;
-import com.google.gerrit.common.data.LabelType;
 import com.google.gerrit.extensions.common.LabelDefinitionInfo;
 import com.google.gerrit.extensions.restapi.AuthException;
 import com.google.gerrit.extensions.restapi.ResourceNotFoundException;
@@ -75,9 +74,7 @@
 
     // set default value
     try (ProjectConfigUpdate u = updateProject(project)) {
-      LabelType labelType = u.getConfig().getLabelSections().get("foo");
-      labelType.setDefaultValue((short) 1);
-      u.getConfig().getLabelSections().put(labelType.getName(), labelType);
+      u.getConfig().updateLabelType("foo", labelType -> labelType.setDefaultValue((short) 1));
       u.save();
     }
 
@@ -100,11 +97,14 @@
 
     // unset rules which are enabled by default
     try (ProjectConfigUpdate u = updateProject(project)) {
-      LabelType labelType = u.getConfig().getLabelSections().get("foo");
-      labelType.setCanOverride(false);
-      labelType.setCopyAllScoresIfNoChange(false);
-      labelType.setAllowPostSubmit(false);
-      u.getConfig().getLabelSections().put(labelType.getName(), labelType);
+      u.getConfig()
+          .updateLabelType(
+              "foo",
+              labelType -> {
+                labelType.setCanOverride(false);
+                labelType.setCopyAllScoresIfNoChange(false);
+                labelType.setAllowPostSubmit(false);
+              });
       u.save();
     }
 
@@ -128,16 +128,19 @@
 
     // set rules which are not enabled by default
     try (ProjectConfigUpdate u = updateProject(project)) {
-      LabelType labelType = u.getConfig().getLabelSections().get("foo");
-      labelType.setCopyAnyScore(true);
-      labelType.setCopyMinScore(true);
-      labelType.setCopyMaxScore(true);
-      labelType.setCopyAllScoresIfNoCodeChange(true);
-      labelType.setCopyAllScoresOnTrivialRebase(true);
-      labelType.setCopyAllScoresOnMergeFirstParentUpdate(true);
-      labelType.setCopyValues(ImmutableList.of((short) -1, (short) 1));
-      labelType.setIgnoreSelfApproval(true);
-      u.getConfig().getLabelSections().put(labelType.getName(), labelType);
+      u.getConfig()
+          .updateLabelType(
+              "foo",
+              labelType -> {
+                labelType.setCopyAnyScore(true);
+                labelType.setCopyMinScore(true);
+                labelType.setCopyMaxScore(true);
+                labelType.setCopyAllScoresIfNoCodeChange(true);
+                labelType.setCopyAllScoresOnTrivialRebase(true);
+                labelType.setCopyAllScoresOnMergeFirstParentUpdate(true);
+                labelType.setCopyValues(ImmutableList.of((short) -1, (short) 1));
+                labelType.setIgnoreSelfApproval(true);
+              });
       u.save();
     }
 
diff --git a/javatests/com/google/gerrit/acceptance/rest/project/ListLabelsIT.java b/javatests/com/google/gerrit/acceptance/rest/project/ListLabelsIT.java
index ef08079..33a0654 100644
--- a/javatests/com/google/gerrit/acceptance/rest/project/ListLabelsIT.java
+++ b/javatests/com/google/gerrit/acceptance/rest/project/ListLabelsIT.java
@@ -27,7 +27,6 @@
 import com.google.gerrit.acceptance.testsuite.project.ProjectOperations;
 import com.google.gerrit.acceptance.testsuite.request.RequestScopeOperations;
 import com.google.gerrit.common.data.LabelFunction;
-import com.google.gerrit.common.data.LabelType;
 import com.google.gerrit.common.data.Permission;
 import com.google.gerrit.entities.Project;
 import com.google.gerrit.entities.RefNames;
@@ -88,9 +87,7 @@
 
     // set default value
     try (ProjectConfigUpdate u = updateProject(project)) {
-      LabelType labelType = u.getConfig().getLabelSections().get("foo");
-      labelType.setDefaultValue((short) 1);
-      u.getConfig().getLabelSections().put(labelType.getName(), labelType);
+      u.getConfig().updateLabelType("foo", labelType -> labelType.setDefaultValue((short) 1));
       u.save();
     }
 
@@ -119,11 +116,14 @@
 
     // unset rules which are enabled by default
     try (ProjectConfigUpdate u = updateProject(project)) {
-      LabelType labelType = u.getConfig().getLabelSections().get("foo");
-      labelType.setCanOverride(false);
-      labelType.setCopyAllScoresIfNoChange(false);
-      labelType.setAllowPostSubmit(false);
-      u.getConfig().getLabelSections().put(labelType.getName(), labelType);
+      u.getConfig()
+          .updateLabelType(
+              "foo",
+              labelType -> {
+                labelType.setCanOverride(false);
+                labelType.setCopyAllScoresIfNoChange(false);
+                labelType.setAllowPostSubmit(false);
+              });
       u.save();
     }
 
@@ -150,16 +150,19 @@
 
     // set rules which are not enabled by default
     try (ProjectConfigUpdate u = updateProject(project)) {
-      LabelType labelType = u.getConfig().getLabelSections().get("foo");
-      labelType.setCopyAnyScore(true);
-      labelType.setCopyMinScore(true);
-      labelType.setCopyMaxScore(true);
-      labelType.setCopyAllScoresIfNoCodeChange(true);
-      labelType.setCopyAllScoresOnTrivialRebase(true);
-      labelType.setCopyAllScoresOnMergeFirstParentUpdate(true);
-      labelType.setCopyValues(ImmutableList.of((short) -1, (short) 1));
-      labelType.setIgnoreSelfApproval(true);
-      u.getConfig().getLabelSections().put(labelType.getName(), labelType);
+      u.getConfig()
+          .updateLabelType(
+              "foo",
+              labelType -> {
+                labelType.setCopyAnyScore(true);
+                labelType.setCopyMinScore(true);
+                labelType.setCopyMaxScore(true);
+                labelType.setCopyAllScoresIfNoCodeChange(true);
+                labelType.setCopyAllScoresOnTrivialRebase(true);
+                labelType.setCopyAllScoresOnMergeFirstParentUpdate(true);
+                labelType.setCopyValues(ImmutableList.of((short) -1, (short) 1));
+                labelType.setIgnoreSelfApproval(true);
+              });
       u.save();
     }
 
diff --git a/javatests/com/google/gerrit/acceptance/rest/project/SetLabelIT.java b/javatests/com/google/gerrit/acceptance/rest/project/SetLabelIT.java
index b08c72b..a1817d9 100644
--- a/javatests/com/google/gerrit/acceptance/rest/project/SetLabelIT.java
+++ b/javatests/com/google/gerrit/acceptance/rest/project/SetLabelIT.java
@@ -26,7 +26,6 @@
 import com.google.gerrit.acceptance.testsuite.project.ProjectOperations;
 import com.google.gerrit.acceptance.testsuite.request.RequestScopeOperations;
 import com.google.gerrit.common.data.LabelFunction;
-import com.google.gerrit.common.data.LabelType;
 import com.google.gerrit.common.data.Permission;
 import com.google.gerrit.entities.RefNames;
 import com.google.gerrit.extensions.common.LabelDefinitionInfo;
@@ -450,9 +449,7 @@
   public void setCanOverride() throws Exception {
     configLabel("foo", LabelFunction.NO_OP);
     try (ProjectConfigUpdate u = updateProject(project)) {
-      LabelType labelType = u.getConfig().getLabelSections().get("foo");
-      labelType.setCanOverride(false);
-      u.getConfig().getLabelSections().put(labelType.getName(), labelType);
+      u.getConfig().updateLabelType("foo", lt -> lt.setCanOverride(false));
       u.save();
     }
     assertThat(gApi.projects().name(project.get()).label("foo").get().canOverride).isNull();
@@ -501,9 +498,7 @@
   public void unsetCopyAnyScore() throws Exception {
     configLabel("foo", LabelFunction.NO_OP);
     try (ProjectConfigUpdate u = updateProject(project)) {
-      LabelType labelType = u.getConfig().getLabelSections().get("foo");
-      labelType.setCopyAnyScore(true);
-      u.getConfig().getLabelSections().put(labelType.getName(), labelType);
+      u.getConfig().updateLabelType("foo", lt -> lt.setCopyAnyScore(true));
       u.save();
     }
     assertThat(gApi.projects().name(project.get()).label("foo").get().copyAnyScore).isTrue();
@@ -537,9 +532,7 @@
   public void unsetCopyMinScore() throws Exception {
     configLabel("foo", LabelFunction.NO_OP);
     try (ProjectConfigUpdate u = updateProject(project)) {
-      LabelType labelType = u.getConfig().getLabelSections().get("foo");
-      labelType.setCopyMinScore(true);
-      u.getConfig().getLabelSections().put(labelType.getName(), labelType);
+      u.getConfig().updateLabelType("foo", lt -> lt.setCopyMinScore(true));
       u.save();
     }
     assertThat(gApi.projects().name(project.get()).label("foo").get().copyMinScore).isTrue();
@@ -573,9 +566,7 @@
   public void unsetCopyMaxScore() throws Exception {
     configLabel("foo", LabelFunction.NO_OP);
     try (ProjectConfigUpdate u = updateProject(project)) {
-      LabelType labelType = u.getConfig().getLabelSections().get("foo");
-      labelType.setCopyMaxScore(true);
-      u.getConfig().getLabelSections().put(labelType.getName(), labelType);
+      u.getConfig().updateLabelType("foo", lt -> lt.setCopyMaxScore(true));
       u.save();
     }
     assertThat(gApi.projects().name(project.get()).label("foo").get().copyMaxScore).isTrue();
@@ -594,9 +585,7 @@
   public void setCopyAllScoresIfNoChange() throws Exception {
     configLabel("foo", LabelFunction.NO_OP);
     try (ProjectConfigUpdate u = updateProject(project)) {
-      LabelType labelType = u.getConfig().getLabelSections().get("foo");
-      labelType.setCopyAllScoresIfNoChange(false);
-      u.getConfig().getLabelSections().put(labelType.getName(), labelType);
+      u.getConfig().updateLabelType("foo", lt -> lt.setCopyAllScoresIfNoChange(false));
       u.save();
     }
     assertThat(gApi.projects().name(project.get()).label("foo").get().copyAllScoresIfNoChange)
@@ -651,9 +640,7 @@
   public void unsetCopyAllScoresIfNoCodeChange() throws Exception {
     configLabel("foo", LabelFunction.NO_OP);
     try (ProjectConfigUpdate u = updateProject(project)) {
-      LabelType labelType = u.getConfig().getLabelSections().get("foo");
-      labelType.setCopyAllScoresIfNoCodeChange(true);
-      u.getConfig().getLabelSections().put(labelType.getName(), labelType);
+      u.getConfig().updateLabelType("foo", lt -> lt.setCopyAllScoresIfNoCodeChange(true));
       u.save();
     }
     assertThat(gApi.projects().name(project.get()).label("foo").get().copyAllScoresIfNoCodeChange)
@@ -691,9 +678,7 @@
   public void unsetCopyAllScoresOnTrivialRebase() throws Exception {
     configLabel("foo", LabelFunction.NO_OP);
     try (ProjectConfigUpdate u = updateProject(project)) {
-      LabelType labelType = u.getConfig().getLabelSections().get("foo");
-      labelType.setCopyAllScoresOnTrivialRebase(true);
-      u.getConfig().getLabelSections().put(labelType.getName(), labelType);
+      u.getConfig().updateLabelType("foo", lt -> lt.setCopyAllScoresOnTrivialRebase(true));
       u.save();
     }
     assertThat(gApi.projects().name(project.get()).label("foo").get().copyAllScoresOnTrivialRebase)
@@ -741,9 +726,7 @@
   public void unsetCopyAllScoresOnMergeFirstParentUpdate() throws Exception {
     configLabel("foo", LabelFunction.NO_OP);
     try (ProjectConfigUpdate u = updateProject(project)) {
-      LabelType labelType = u.getConfig().getLabelSections().get("foo");
-      labelType.setCopyAllScoresOnMergeFirstParentUpdate(true);
-      u.getConfig().getLabelSections().put(labelType.getName(), labelType);
+      u.getConfig().updateLabelType("foo", lt -> lt.setCopyAllScoresOnMergeFirstParentUpdate(true));
       u.save();
     }
     assertThat(
@@ -791,9 +774,8 @@
   public void unsetCopyValues() throws Exception {
     configLabel("foo", LabelFunction.NO_OP);
     try (ProjectConfigUpdate u = updateProject(project)) {
-      LabelType labelType = u.getConfig().getLabelSections().get("foo");
-      labelType.setCopyValues(ImmutableList.of((short) -1, (short) 1));
-      u.getConfig().getLabelSections().put(labelType.getName(), labelType);
+      u.getConfig()
+          .updateLabelType("foo", lt -> lt.setCopyValues(ImmutableList.of((short) -1, (short) 1)));
       u.save();
     }
     assertThat(gApi.projects().name(project.get()).label("foo").get().copyValues).isNotEmpty();
@@ -812,9 +794,7 @@
   public void setAllowPostSubmit() throws Exception {
     configLabel("foo", LabelFunction.NO_OP);
     try (ProjectConfigUpdate u = updateProject(project)) {
-      LabelType labelType = u.getConfig().getLabelSections().get("foo");
-      labelType.setAllowPostSubmit(false);
-      u.getConfig().getLabelSections().put(labelType.getName(), labelType);
+      u.getConfig().updateLabelType("foo", lt -> lt.setAllowPostSubmit(false));
       u.save();
     }
     assertThat(gApi.projects().name(project.get()).label("foo").get().allowPostSubmit).isNull();
@@ -863,9 +843,7 @@
   public void unsetIgnoreSelfApproval() throws Exception {
     configLabel("foo", LabelFunction.NO_OP);
     try (ProjectConfigUpdate u = updateProject(project)) {
-      LabelType labelType = u.getConfig().getLabelSections().get("foo");
-      labelType.setIgnoreSelfApproval(true);
-      u.getConfig().getLabelSections().put(labelType.getName(), labelType);
+      u.getConfig().updateLabelType("foo", lt -> lt.setIgnoreSelfApproval(true));
       u.save();
     }
     assertThat(gApi.projects().name(project.get()).label("foo").get().ignoreSelfApproval).isTrue();
diff --git a/javatests/com/google/gerrit/acceptance/server/event/CommentAddedEventIT.java b/javatests/com/google/gerrit/acceptance/server/event/CommentAddedEventIT.java
index 8469fff..17eb534 100644
--- a/javatests/com/google/gerrit/acceptance/server/event/CommentAddedEventIT.java
+++ b/javatests/com/google/gerrit/acceptance/server/event/CommentAddedEventIT.java
@@ -61,8 +61,8 @@
 
   private void saveLabelConfig() throws Exception {
     try (ProjectConfigUpdate u = updateProject(project)) {
-      u.getConfig().getLabelSections().put(label.getName(), label);
-      u.getConfig().getLabelSections().put(pLabel.getName(), pLabel);
+      u.getConfig().upsertLabelType(label);
+      u.getConfig().upsertLabelType(pLabel);
       u.save();
     }
   }
diff --git a/javatests/com/google/gerrit/acceptance/server/mail/ChangeNotificationsIT.java b/javatests/com/google/gerrit/acceptance/server/mail/ChangeNotificationsIT.java
index d74cd71..76514ec 100644
--- a/javatests/com/google/gerrit/acceptance/server/mail/ChangeNotificationsIT.java
+++ b/javatests/com/google/gerrit/acceptance/server/mail/ChangeNotificationsIT.java
@@ -1500,7 +1500,7 @@
       throws Exception {
     for (SubmitType submitType : SubmitType.values()) {
       try (ProjectConfigUpdate u = updateProject(project)) {
-        u.getConfig().getProject().setSubmitType(submitType);
+        u.getConfig().updateProject(p -> p.setSubmitType(submitType));
         u.save();
       }
 
diff --git a/javatests/com/google/gerrit/acceptance/server/project/CustomLabelIT.java b/javatests/com/google/gerrit/acceptance/server/project/CustomLabelIT.java
index 1d5204b..813a715 100644
--- a/javatests/com/google/gerrit/acceptance/server/project/CustomLabelIT.java
+++ b/javatests/com/google/gerrit/acceptance/server/project/CustomLabelIT.java
@@ -32,6 +32,7 @@
 import static com.google.gerrit.server.project.testing.TestLabels.value;
 import static com.google.gerrit.testing.GerritJUnit.assertThrows;
 
+import com.google.common.collect.ImmutableList;
 import com.google.gerrit.acceptance.AbstractDaemonTest;
 import com.google.gerrit.acceptance.ExtensionRegistry;
 import com.google.gerrit.acceptance.ExtensionRegistry.Registration;
@@ -48,39 +49,38 @@
 import com.google.gerrit.extensions.restapi.ResourceConflictException;
 import com.google.gerrit.server.project.ProjectConfig;
 import com.google.inject.Inject;
-import java.util.Arrays;
 import org.junit.Before;
 import org.junit.Test;
 
 @NoHttpd
 public class CustomLabelIT extends AbstractDaemonTest {
+  private static final String LABEL_NAME = "CustomLabel";
+  private static final LabelType LABEL =
+      label("CustomLabel", value(1, "Positive"), value(0, "No score"), value(-1, "Negative"));
+  private static final String P_LABEL_NAME = "CustomLabel2";
+  private static final LabelType P =
+      label("CustomLabel2", value(1, "Positive"), value(0, "No score"));
 
   @Inject private ProjectOperations projectOperations;
   @Inject private ExtensionRegistry extensionRegistry;
 
-  private final LabelType label =
-      label("CustomLabel", value(1, "Positive"), value(0, "No score"), value(-1, "Negative"));
-
-  private final LabelType P = label("CustomLabel2", value(1, "Positive"), value(0, "No score"));
-
   @Before
   public void setUp() throws Exception {
     projectOperations
         .project(project)
         .forUpdate()
-        .add(allowLabel(label.getName()).ref("refs/heads/*").group(ANONYMOUS_USERS).range(-1, 1))
-        .add(allowLabel(P.getName()).ref("refs/heads/*").group(ANONYMOUS_USERS).range(0, 1))
+        .add(allowLabel(LABEL_NAME).ref("refs/heads/*").group(ANONYMOUS_USERS).range(-1, 1))
+        .add(allowLabel(P_LABEL_NAME).ref("refs/heads/*").group(ANONYMOUS_USERS).range(0, 1))
         .update();
   }
 
   @Test
   public void customLabelNoOp_NegativeVoteNotBlock() throws Exception {
-    label.setFunction(NO_OP);
-    saveLabelConfig();
+    saveLabelConfig(LABEL.toBuilder().setFunction(NO_OP));
     PushOneCommit.Result r = createChange();
-    revision(r).review(new ReviewInput().label(label.getName(), -1));
+    revision(r).review(new ReviewInput().label(LABEL_NAME, -1));
     ChangeInfo c = getWithLabels(r);
-    LabelInfo q = c.labels.get(label.getName());
+    LabelInfo q = c.labels.get(LABEL_NAME);
     assertThat(q.all).hasSize(1);
     assertThat(q.approved).isNull();
     assertThat(q.recommended).isNull();
@@ -91,12 +91,11 @@
 
   @Test
   public void customLabelNoBlock_NegativeVoteNotBlock() throws Exception {
-    label.setFunction(NO_BLOCK);
-    saveLabelConfig();
+    saveLabelConfig(LABEL.toBuilder().setFunction(NO_BLOCK));
     PushOneCommit.Result r = createChange();
-    revision(r).review(new ReviewInput().label(label.getName(), -1));
+    revision(r).review(new ReviewInput().label(LABEL_NAME, -1));
     ChangeInfo c = getWithLabels(r);
-    LabelInfo q = c.labels.get(label.getName());
+    LabelInfo q = c.labels.get(LABEL_NAME);
     assertThat(q.all).hasSize(1);
     assertThat(q.approved).isNull();
     assertThat(q.recommended).isNull();
@@ -107,12 +106,11 @@
 
   @Test
   public void customLabelMaxNoBlock_NegativeVoteNotBlock() throws Exception {
-    label.setFunction(MAX_NO_BLOCK);
-    saveLabelConfig();
+    saveLabelConfig(LABEL.toBuilder().setFunction(MAX_NO_BLOCK));
     PushOneCommit.Result r = createChange();
-    revision(r).review(new ReviewInput().label(label.getName(), -1));
+    revision(r).review(new ReviewInput().label(LABEL_NAME, -1));
     ChangeInfo c = getWithLabels(r);
-    LabelInfo q = c.labels.get(label.getName());
+    LabelInfo q = c.labels.get(LABEL_NAME);
     assertThat(q.all).hasSize(1);
     assertThat(q.approved).isNull();
     assertThat(q.recommended).isNull();
@@ -123,16 +121,14 @@
 
   @Test
   public void customLabelMaxNoBlock_MaxVoteSubmittable() throws Exception {
-    label.setFunction(MAX_NO_BLOCK);
-    P.setFunction(NO_OP);
-    saveLabelConfig();
+    saveLabelConfig(LABEL.toBuilder().setFunction(MAX_NO_BLOCK), P.toBuilder().setFunction(NO_OP));
     PushOneCommit.Result r = createChange();
     assertThat(info(r.getChangeId()).submittable).isNull();
-    revision(r).review(ReviewInput.approve().label(label.getName(), 1));
+    revision(r).review(ReviewInput.approve().label(LABEL_NAME, 1));
 
     ChangeInfo c = getWithLabels(r);
     assertThat(c.submittable).isTrue();
-    LabelInfo q = c.labels.get(label.getName());
+    LabelInfo q = c.labels.get(LABEL_NAME);
     assertThat(q.all).hasSize(1);
     assertThat(q.approved).isNotNull();
     assertThat(q.recommended).isNull();
@@ -143,12 +139,11 @@
 
   @Test
   public void customLabelAnyWithBlock_NegativeVoteBlock() throws Exception {
-    label.setFunction(ANY_WITH_BLOCK);
-    saveLabelConfig();
+    saveLabelConfig(LABEL.toBuilder().setFunction(ANY_WITH_BLOCK));
     PushOneCommit.Result r = createChange();
-    revision(r).review(new ReviewInput().label(label.getName(), -1));
+    revision(r).review(new ReviewInput().label(LABEL_NAME, -1));
     ChangeInfo c = getWithLabels(r);
-    LabelInfo q = c.labels.get(label.getName());
+    LabelInfo q = c.labels.get(LABEL_NAME);
     assertThat(q.all).hasSize(1);
     assertThat(q.approved).isNull();
     assertThat(q.recommended).isNull();
@@ -170,19 +165,18 @@
   public void customLabelAnyWithBlock_Addreviewer_ZeroVote() throws Exception {
     TestListener testListener = new TestListener();
     try (Registration registration = extensionRegistry.newRegistration().add(testListener)) {
-      P.setFunction(ANY_WITH_BLOCK);
-      saveLabelConfig();
+      saveLabelConfig(P.toBuilder().setFunction(ANY_WITH_BLOCK));
       PushOneCommit.Result r = createChange();
       AddReviewerInput in = new AddReviewerInput();
       in.reviewer = user.email();
       gApi.changes().id(r.getChangeId()).addReviewer(in);
 
-      ReviewInput input = new ReviewInput().label(P.getName(), 0);
+      ReviewInput input = new ReviewInput().label(P_LABEL_NAME, 0);
       input.message = "foo";
 
       revision(r).review(input);
       ChangeInfo c = getWithLabels(r);
-      LabelInfo q = c.labels.get(P.getName());
+      LabelInfo q = c.labels.get(P_LABEL_NAME);
       assertThat(q.all).hasSize(1);
       assertThat(q.approved).isNull();
       assertThat(q.recommended).isNull();
@@ -196,12 +190,11 @@
 
   @Test
   public void customLabelMaxWithBlock_NegativeVoteBlock() throws Exception {
-    label.setFunction(MAX_WITH_BLOCK);
-    saveLabelConfig();
+    saveLabelConfig(LABEL.toBuilder().setFunction(MAX_WITH_BLOCK));
     PushOneCommit.Result r = createChange();
-    revision(r).review(new ReviewInput().label(label.getName(), -1));
+    revision(r).review(new ReviewInput().label(LABEL_NAME, -1));
     ChangeInfo c = getWithLabels(r);
-    LabelInfo q = c.labels.get(label.getName());
+    LabelInfo q = c.labels.get(LABEL_NAME);
     assertThat(q.all).hasSize(1);
     assertThat(q.approved).isNull();
     assertThat(q.recommended).isNull();
@@ -212,16 +205,15 @@
 
   @Test
   public void customLabelMaxWithBlock_MaxVoteSubmittable() throws Exception {
-    label.setFunction(MAX_WITH_BLOCK);
-    P.setFunction(NO_OP);
-    saveLabelConfig();
+    saveLabelConfig(
+        LABEL.toBuilder().setFunction(MAX_WITH_BLOCK), P.toBuilder().setFunction(NO_OP));
     PushOneCommit.Result r = createChange();
     assertThat(info(r.getChangeId()).submittable).isNull();
-    revision(r).review(ReviewInput.approve().label(label.getName(), 1));
+    revision(r).review(ReviewInput.approve().label(LABEL_NAME, 1));
 
     ChangeInfo c = getWithLabels(r);
     assertThat(c.submittable).isTrue();
-    LabelInfo q = c.labels.get(label.getName());
+    LabelInfo q = c.labels.get(LABEL_NAME);
     assertThat(q.all).hasSize(1);
     assertThat(q.approved).isNotNull();
     assertThat(q.recommended).isNull();
@@ -232,13 +224,12 @@
 
   @Test
   public void customLabelMaxWithBlock_MaxVoteNegativeVoteBlock() throws Exception {
-    label.setFunction(MAX_WITH_BLOCK);
-    saveLabelConfig();
+    saveLabelConfig(LABEL.toBuilder().setFunction(MAX_WITH_BLOCK));
     PushOneCommit.Result r = createChange();
-    revision(r).review(new ReviewInput().label(label.getName(), 1));
-    revision(r).review(new ReviewInput().label(label.getName(), -1));
+    revision(r).review(new ReviewInput().label(LABEL_NAME, 1));
+    revision(r).review(new ReviewInput().label(LABEL_NAME, -1));
     ChangeInfo c = getWithLabels(r);
-    LabelInfo q = c.labels.get(label.getName());
+    LabelInfo q = c.labels.get(LABEL_NAME);
     assertThat(q.all).hasSize(1);
     assertThat(q.approved).isNull();
     assertThat(q.recommended).isNull();
@@ -249,10 +240,9 @@
 
   @Test
   public void customLabel_DisallowPostSubmit() throws Exception {
-    label.setFunction(NO_OP);
-    label.setAllowPostSubmit(false);
-    P.setFunction(NO_OP);
-    saveLabelConfig();
+    saveLabelConfig(
+        LABEL.toBuilder().setFunction(NO_OP).setAllowPostSubmit(false),
+        P.toBuilder().setFunction(NO_OP));
 
     PushOneCommit.Result r = createChange();
     revision(r).review(ReviewInput.approve());
@@ -260,20 +250,20 @@
 
     ChangeInfo info = getWithLabels(r);
     assertPermitted(info, "Code-Review", 2);
-    assertPermitted(info, P.getName(), 0, 1);
-    assertPermitted(info, label.getName());
+    assertPermitted(info, P_LABEL_NAME, 0, 1);
+    assertPermitted(info, LABEL_NAME);
 
     ReviewInput postSubmitReview1 = new ReviewInput();
     postSubmitReview1.label(P.getName(), P.getMax().getValue());
     revision(r).review(postSubmitReview1);
 
     ReviewInput postSubmitReview2 = new ReviewInput();
-    postSubmitReview2.label(label.getName(), label.getMax().getValue());
+    postSubmitReview2.label(LABEL.getName(), LABEL.getMax().getValue());
     ResourceConflictException thrown =
         assertThrows(ResourceConflictException.class, () -> revision(r).review(postSubmitReview2));
     assertThat(thrown)
         .hasMessageThat()
-        .contains("Voting on labels disallowed after submit: " + label.getName());
+        .contains("Voting on labels disallowed after submit: " + LABEL_NAME);
   }
 
   @Test
@@ -331,10 +321,9 @@
 
   @Test
   public void customLabel_withBranch() throws Exception {
-    label.setRefPatterns(Arrays.asList("master"));
-    saveLabelConfig();
+    saveLabelConfig(LABEL.toBuilder().setRefPatterns(ImmutableList.of("master")));
     ProjectConfig cfg = projectCache.get(project).orElseThrow(illegalState(project)).getConfig();
-    assertThat(cfg.getLabelSections().get(label.getName()).getRefPatterns()).contains("master");
+    assertThat(cfg.getLabelSections().get(LABEL_NAME).getRefPatterns()).contains("master");
   }
 
   private void assertLabelStatus(String changeId, String testLabel) throws Exception {
@@ -348,10 +337,11 @@
     assertThat(labelInfo.blocking).isNull();
   }
 
-  private void saveLabelConfig() throws Exception {
+  private void saveLabelConfig(LabelType.Builder... builders) throws Exception {
     try (ProjectConfigUpdate u = updateProject(project)) {
-      u.getConfig().getLabelSections().put(label.getName(), label);
-      u.getConfig().getLabelSections().put(P.getName(), P);
+      for (LabelType.Builder b : builders) {
+        u.getConfig().upsertLabelType(b.build());
+      }
       u.save();
     }
   }
diff --git a/javatests/com/google/gerrit/acceptance/server/project/ProjectWatchIT.java b/javatests/com/google/gerrit/acceptance/server/project/ProjectWatchIT.java
index a9114b9..ff26fec 100644
--- a/javatests/com/google/gerrit/acceptance/server/project/ProjectWatchIT.java
+++ b/javatests/com/google/gerrit/acceptance/server/project/ProjectWatchIT.java
@@ -50,15 +50,15 @@
   @Test
   public void newPatchSetsNotifyConfig() throws Exception {
     Address addr = Address.create("Watcher", "watcher@example.com");
-    NotifyConfig nc = new NotifyConfig();
-    nc.addEmail(addr);
+    NotifyConfig.Builder nc = NotifyConfig.builder();
+    nc.addAddress(addr);
     nc.setName("new-patch-set");
     nc.setHeader(NotifyConfig.Header.CC);
-    nc.setTypes(EnumSet.of(NotifyType.NEW_PATCHSETS));
+    nc.setNotify(EnumSet.of(NotifyType.NEW_PATCHSETS));
     nc.setFilter("message:sekret");
 
     try (ProjectConfigUpdate u = updateProject(project)) {
-      u.getConfig().putNotifyConfig("watch", nc);
+      u.getConfig().putNotifyConfig("watch", nc.build());
       u.save();
     }
 
@@ -91,14 +91,14 @@
   @Test
   public void noNotificationForPrivateChangesForWatchersInNotifyConfig() throws Exception {
     Address addr = Address.create("Watcher", "watcher@example.com");
-    NotifyConfig nc = new NotifyConfig();
-    nc.addEmail(addr);
+    NotifyConfig.Builder nc = NotifyConfig.builder();
+    nc.addAddress(addr);
     nc.setName("team");
     nc.setHeader(NotifyConfig.Header.TO);
-    nc.setTypes(EnumSet.of(NotifyType.NEW_CHANGES, NotifyType.ALL_COMMENTS));
+    nc.setNotify(EnumSet.of(NotifyType.NEW_CHANGES, NotifyType.ALL_COMMENTS));
 
     try (ProjectConfigUpdate u = updateProject(project)) {
-      u.getConfig().putNotifyConfig("team", nc);
+      u.getConfig().putNotifyConfig("team", nc.build());
       u.save();
     }
 
@@ -123,14 +123,14 @@
   public void noNotificationForChangeThatIsTurnedPrivateForWatchersInNotifyConfig()
       throws Exception {
     Address addr = Address.create("Watcher", "watcher@example.com");
-    NotifyConfig nc = new NotifyConfig();
-    nc.addEmail(addr);
+    NotifyConfig.Builder nc = NotifyConfig.builder();
+    nc.addAddress(addr);
     nc.setName("team");
     nc.setHeader(NotifyConfig.Header.TO);
-    nc.setTypes(EnumSet.of(NotifyType.NEW_PATCHSETS));
+    nc.setNotify(EnumSet.of(NotifyType.NEW_PATCHSETS));
 
     try (ProjectConfigUpdate u = updateProject(project)) {
-      u.getConfig().putNotifyConfig("team", nc);
+      u.getConfig().putNotifyConfig("team", nc.build());
       u.save();
     }
 
@@ -152,14 +152,14 @@
   @Test
   public void noNotificationForWipChangesForWatchersInNotifyConfig() throws Exception {
     Address addr = Address.create("Watcher", "watcher@example.com");
-    NotifyConfig nc = new NotifyConfig();
-    nc.addEmail(addr);
+    NotifyConfig.Builder nc = NotifyConfig.builder();
+    nc.addAddress(addr);
     nc.setName("team");
     nc.setHeader(NotifyConfig.Header.TO);
-    nc.setTypes(EnumSet.of(NotifyType.NEW_CHANGES, NotifyType.ALL_COMMENTS));
+    nc.setNotify(EnumSet.of(NotifyType.NEW_CHANGES, NotifyType.ALL_COMMENTS));
 
     try (ProjectConfigUpdate u = updateProject(project)) {
-      u.getConfig().putNotifyConfig("team", nc);
+      u.getConfig().putNotifyConfig("team", nc.build());
       u.save();
     }
 
@@ -183,14 +183,14 @@
   @Test
   public void noNotificationForChangeThatIsTurnedWipForWatchersInNotifyConfig() throws Exception {
     Address addr = Address.create("Watcher", "watcher@example.com");
-    NotifyConfig nc = new NotifyConfig();
-    nc.addEmail(addr);
+    NotifyConfig.Builder nc = NotifyConfig.builder();
+    nc.addAddress(addr);
     nc.setName("team");
     nc.setHeader(NotifyConfig.Header.TO);
-    nc.setTypes(EnumSet.of(NotifyType.NEW_PATCHSETS));
+    nc.setNotify(EnumSet.of(NotifyType.NEW_PATCHSETS));
 
     try (ProjectConfigUpdate u = updateProject(project)) {
-      u.getConfig().putNotifyConfig("team", nc);
+      u.getConfig().putNotifyConfig("team", nc.build());
       u.save();
     }
 
diff --git a/javatests/com/google/gerrit/acceptance/server/rules/IgnoreSelfApprovalRuleIT.java b/javatests/com/google/gerrit/acceptance/server/rules/IgnoreSelfApprovalRuleIT.java
index 1c820af..90d4e09 100644
--- a/javatests/com/google/gerrit/acceptance/server/rules/IgnoreSelfApprovalRuleIT.java
+++ b/javatests/com/google/gerrit/acceptance/server/rules/IgnoreSelfApprovalRuleIT.java
@@ -89,7 +89,7 @@
       if (localLabelSections.isEmpty()) {
         localLabelSections.putAll(projectCache.getAllProjects().getConfig().getLabelSections());
       }
-      localLabelSections.get(labelName).setIgnoreSelfApproval(newState);
+      u.getConfig().updateLabelType(labelName, lt -> lt.setIgnoreSelfApproval(newState));
       u.save();
     }
   }
diff --git a/javatests/com/google/gerrit/acceptance/testsuite/project/ProjectOperationsImplTest.java b/javatests/com/google/gerrit/acceptance/testsuite/project/ProjectOperationsImplTest.java
index 65c7b5c..c8899b9 100644
--- a/javatests/com/google/gerrit/acceptance/testsuite/project/ProjectOperationsImplTest.java
+++ b/javatests/com/google/gerrit/acceptance/testsuite/project/ProjectOperationsImplTest.java
@@ -106,7 +106,7 @@
     assertThat(cachedProjectConfig1).isNotSameInstanceAs(projectConfig);
     assertThat(cachedProjectConfig1.getProject().getDescription()).isEmpty();
     assertThat(projectConfig.getProject().getDescription()).isEmpty();
-    projectConfig.getProject().setDescription("my fancy project");
+    projectConfig.updateProject(p -> p.setDescription("my fancy project"));
 
     ProjectConfig cachedProjectConfig2 =
         projectCache.get(key).orElseThrow(illegalState(project)).getConfig();
diff --git a/javatests/com/google/gerrit/common/data/LabelFunctionTest.java b/javatests/com/google/gerrit/common/data/LabelFunctionTest.java
index 6f5232b..8fea072 100644
--- a/javatests/com/google/gerrit/common/data/LabelFunctionTest.java
+++ b/javatests/com/google/gerrit/common/data/LabelFunctionTest.java
@@ -87,12 +87,12 @@
   private static LabelType makeLabel() {
     List<LabelValue> values = new ArrayList<>();
     // The label text is irrelevant here, only the numerical value is used
-    values.add(new LabelValue((short) -2, "Great job, please fix compilation."));
-    values.add(new LabelValue((short) -1, "Really good, please make some minor changes."));
-    values.add(new LabelValue((short) 0, "No vote."));
-    values.add(new LabelValue((short) 1, "Closest thing perfection."));
-    values.add(new LabelValue((short) 2, "Perfect!"));
-    return new LabelType(LABEL_NAME, values);
+    values.add(LabelValue.create((short) -2, "Great job, please fix compilation."));
+    values.add(LabelValue.create((short) -1, "Really good, please make some minor changes."));
+    values.add(LabelValue.create((short) 0, "No vote."));
+    values.add(LabelValue.create((short) 1, "Closest thing perfection."));
+    values.add(LabelValue.create((short) 2, "Perfect!"));
+    return LabelType.create(LABEL_NAME, values);
   }
 
   private static PatchSetApproval makeApproval(int value) {
diff --git a/javatests/com/google/gerrit/common/data/LabelTypeTest.java b/javatests/com/google/gerrit/common/data/LabelTypeTest.java
index 6c3befb..76ea6e1 100644
--- a/javatests/com/google/gerrit/common/data/LabelTypeTest.java
+++ b/javatests/com/google/gerrit/common/data/LabelTypeTest.java
@@ -22,26 +22,26 @@
 public class LabelTypeTest {
   @Test
   public void sortLabelValues() {
-    LabelValue v0 = new LabelValue((short) 0, "Zero");
-    LabelValue v1 = new LabelValue((short) 1, "One");
-    LabelValue v2 = new LabelValue((short) 2, "Two");
-    LabelType types = new LabelType("Label", ImmutableList.of(v2, v0, v1));
+    LabelValue v0 = LabelValue.create((short) 0, "Zero");
+    LabelValue v1 = LabelValue.create((short) 1, "One");
+    LabelValue v2 = LabelValue.create((short) 2, "Two");
+    LabelType types = LabelType.create("Label", ImmutableList.of(v2, v0, v1));
     assertThat(types.getValues()).containsExactly(v0, v1, v2).inOrder();
   }
 
   @Test
   public void insertMissingLabelValues() {
-    LabelValue v0 = new LabelValue((short) 0, "Zero");
-    LabelValue v2 = new LabelValue((short) 2, "Two");
-    LabelValue v5 = new LabelValue((short) 5, "Five");
-    LabelType types = new LabelType("Label", ImmutableList.of(v2, v5, v0));
+    LabelValue v0 = LabelValue.create((short) 0, "Zero");
+    LabelValue v2 = LabelValue.create((short) 2, "Two");
+    LabelValue v5 = LabelValue.create((short) 5, "Five");
+    LabelType types = LabelType.create("Label", ImmutableList.of(v2, v5, v0));
     assertThat(types.getValues())
         .containsExactly(
             v0,
-            new LabelValue((short) 1, ""),
+            LabelValue.create((short) 1, ""),
             v2,
-            new LabelValue((short) 3, ""),
-            new LabelValue((short) 4, ""),
+            LabelValue.create((short) 3, ""),
+            LabelValue.create((short) 4, ""),
             v5)
         .inOrder();
   }
diff --git a/javatests/com/google/gerrit/server/change/LabelNormalizerTest.java b/javatests/com/google/gerrit/server/change/LabelNormalizerTest.java
index c259e60..ba8485b 100644
--- a/javatests/com/google/gerrit/server/change/LabelNormalizerTest.java
+++ b/javatests/com/google/gerrit/server/change/LabelNormalizerTest.java
@@ -105,7 +105,7 @@
     }
     LabelType lt =
         label("Verified", value(1, "Verified"), value(0, "No score"), value(-1, "Fails"));
-    pc.getLabelSections().put(lt.getName(), lt);
+    pc.upsertLabelType(lt);
     save(pc);
   }
 
diff --git a/javatests/com/google/gerrit/server/permissions/RefControlTest.java b/javatests/com/google/gerrit/server/permissions/RefControlTest.java
index 33446e4..9029301 100644
--- a/javatests/com/google/gerrit/server/permissions/RefControlTest.java
+++ b/javatests/com/google/gerrit/server/permissions/RefControlTest.java
@@ -207,7 +207,7 @@
         ProjectConfig allProjectsConfig = projectConfigFactory.create(allProjectsName);
         allProjectsConfig.load(md);
         LabelType cr = TestLabels.codeReview();
-        allProjectsConfig.getLabelSections().put(cr.getName(), cr);
+        allProjectsConfig.upsertLabelType(cr);
         allProjectsConfig.commit(md);
       }
     }
@@ -217,7 +217,7 @@
     try (MetaDataUpdate md = metaDataUpdateFactory.create(localKey)) {
       ProjectConfig newLocal = projectConfigFactory.create(localKey);
       newLocal.load(md);
-      newLocal.getProject().setParentName(parentKey);
+      newLocal.updateProject(p -> p.setParent(parentKey));
       newLocal.commit(md);
     }
 
diff --git a/javatests/com/google/gerrit/server/query/change/AbstractQueryChangesTest.java b/javatests/com/google/gerrit/server/query/change/AbstractQueryChangesTest.java
index 331bb4c..4104017 100644
--- a/javatests/com/google/gerrit/server/query/change/AbstractQueryChangesTest.java
+++ b/javatests/com/google/gerrit/server/query/change/AbstractQueryChangesTest.java
@@ -1026,7 +1026,7 @@
     try (MetaDataUpdate md = metaDataUpdateFactory.create(project)) {
       ProjectConfig cfg = projectConfigFactory.create(project);
       cfg.load(md);
-      cfg.getLabelSections().put(verified.getName(), verified);
+      cfg.upsertLabelType(verified);
       cfg.commit(md);
     }
     projectCache.evict(project);
diff --git a/javatests/com/google/gerrit/server/rules/IgnoreSelfApprovalRuleTest.java b/javatests/com/google/gerrit/server/rules/IgnoreSelfApprovalRuleTest.java
index d8af0e5..85a3207 100644
--- a/javatests/com/google/gerrit/server/rules/IgnoreSelfApprovalRuleTest.java
+++ b/javatests/com/google/gerrit/server/rules/IgnoreSelfApprovalRuleTest.java
@@ -72,12 +72,12 @@
   private static LabelType makeLabel(String labelName) {
     List<LabelValue> values = new ArrayList<>();
     // The label text is irrelevant here, only the numerical value is used
-    values.add(new LabelValue((short) -2, "-2"));
-    values.add(new LabelValue((short) -1, "-1"));
-    values.add(new LabelValue((short) 0, "No vote."));
-    values.add(new LabelValue((short) 1, "+1"));
-    values.add(new LabelValue((short) 2, "+2"));
-    return new LabelType(labelName, values);
+    values.add(LabelValue.create((short) -2, "-2"));
+    values.add(LabelValue.create((short) -1, "-1"));
+    values.add(LabelValue.create((short) 0, "No vote."));
+    values.add(LabelValue.create((short) 1, "+1"));
+    values.add(LabelValue.create((short) 2, "+2"));
+    return LabelType.create(labelName, values);
   }
 
   private static PatchSetApproval makeApproval(LabelId labelId, Account.Id accountId, int value) {
diff --git a/javatests/com/google/gerrit/server/schema/AllProjectsCreatorTest.java b/javatests/com/google/gerrit/server/schema/AllProjectsCreatorTest.java
index eceec8b..9cf4896 100644
--- a/javatests/com/google/gerrit/server/schema/AllProjectsCreatorTest.java
+++ b/javatests/com/google/gerrit/server/schema/AllProjectsCreatorTest.java
@@ -44,12 +44,12 @@
 
 public class AllProjectsCreatorTest {
   private static final LabelType TEST_LABEL =
-      new LabelType(
+      LabelType.create(
           "Test-Label",
           ImmutableList.of(
-              new LabelValue((short) 2, "Two"),
-              new LabelValue((short) 0, "Zero"),
-              new LabelValue((short) 1, "One")));
+              LabelValue.create((short) 2, "Two"),
+              LabelValue.create((short) 0, "Zero"),
+              LabelValue.create((short) 1, "One")));
 
   private static final String TEST_LABEL_STRING =
       String.join(
diff --git a/lib/BUILD b/lib/BUILD
index d3ef4b9..0110047 100644
--- a/lib/BUILD
+++ b/lib/BUILD
@@ -160,7 +160,7 @@
     name = "args4j",
     data = ["//lib:LICENSE-args4j"],
     visibility = ["//visibility:public"],
-    exports = ["@args4j-intern//jar"],
+    exports = ["@args4j//jar"],
 )
 
 java_library(
diff --git a/lib/polymer_externs/BUILD b/lib/polymer_externs/BUILD
deleted file mode 100644
index f07aa2f..0000000
--- a/lib/polymer_externs/BUILD
+++ /dev/null
@@ -1,24 +0,0 @@
-# Copyright (C) 2017 The Android Open Source Project
-#
-# Licensed under the Apache License, Version 2.0 (the "License");
-# you may not use this file except in compliance with the License.
-# You may obtain a copy of the License at
-#
-# http://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
-
-load("@io_bazel_rules_closure//closure:defs.bzl", "closure_js_library")
-
-package(default_visibility = ["//visibility:public"])
-
-closure_js_library(
-    name = "polymer_closure",
-    srcs = ["@polymer_closure//file"],
-    data = ["//lib:LICENSE-Apache2.0"],
-    no_closure_library = True,
-)
diff --git a/package.json b/package.json
index 0331079..d051c41 100644
--- a/package.json
+++ b/package.json
@@ -5,6 +5,7 @@
   "dependencies": {},
   "devDependencies": {
     "@bazel/rollup": "^1.6.1",
+    "@bazel/terser": "^1.7.0",
     "@bazel/typescript": "^1.6.1",
     "eslint": "^6.6.0",
     "eslint-config-google": "^0.13.0",
@@ -16,6 +17,7 @@
     "gts": "^2.0.2",
     "polymer-cli": "^1.9.11",
     "prettier": "2.0.5",
+    "terser": "^4.8.0",
     "typescript": "3.8.2"
   },
   "scripts": {
diff --git a/plugins/BUILD b/plugins/BUILD
index a071bde..943471a 100644
--- a/plugins/BUILD
+++ b/plugins/BUILD
@@ -49,6 +49,7 @@
     "//java/com/google/gerrit/server/audit",
     "//java/com/google/gerrit/server/cache/mem",
     "//java/com/google/gerrit/server/cache/serialize",
+    "//java/com/google/gerrit/server/data",
     "//java/com/google/gerrit/server/logging",
     "//java/com/google/gerrit/server/schema",
     "//java/com/google/gerrit/server/util/time",
diff --git a/plugins/delete-project b/plugins/delete-project
index 7671def..f420d06 160000
--- a/plugins/delete-project
+++ b/plugins/delete-project
@@ -1 +1 @@
-Subproject commit 7671def07882aab89b19eb7496418588ea7375d9
+Subproject commit f420d06562b97eab26a627baa7722c7f84d95763
diff --git a/plugins/replication b/plugins/replication
index b0ecbd3..ced7fc3 160000
--- a/plugins/replication
+++ b/plugins/replication
@@ -1 +1 @@
-Subproject commit b0ecbd3c88fd0d8b19112e33049564e25ac5fc39
+Subproject commit ced7fc318feb76e2fc6d549669c5f5d8d905add5
diff --git a/polygerrit-ui/app/externs/BUILD b/polygerrit-ui/app/externs/BUILD
deleted file mode 100644
index 26ead9a..0000000
--- a/polygerrit-ui/app/externs/BUILD
+++ /dev/null
@@ -1,25 +0,0 @@
-# Copyright (C) 2018 The Android Open Source Project
-#
-# Licensed under the Apache License, Version 2.0 (the "License");
-# you may not use this file except in compliance with the License.
-# You may obtain a copy of the License at
-#
-# http://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
-
-load("@io_bazel_rules_closure//closure:defs.bzl", "closure_js_library")
-
-package(
-    default_visibility = ["//visibility:public"],
-)
-
-closure_js_library(
-    name = "plugin",
-    srcs = ["plugin.js"],
-    no_closure_library = True,
-)
diff --git a/polygerrit-ui/app/externs/plugin.js b/polygerrit-ui/app/externs/plugin.js
deleted file mode 100644
index c88c724..0000000
--- a/polygerrit-ui/app/externs/plugin.js
+++ /dev/null
@@ -1,30 +0,0 @@
-/**
- * @license
- * Copyright (C) 2018 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-/**
- * @fileoverview Closure compiler externs for the Gerrit UI plugins.
- * @externs
- */
-
-/* eslint-disable no-var */
-
-var Gerrit = {};
-
-/**
- * @param {!Function} callback
- */
-Gerrit.install = function(callback) {};
diff --git a/tools/bzl/js.bzl b/tools/bzl/js.bzl
index 5440b88..eeb5e6b 100644
--- a/tools/bzl/js.bzl
+++ b/tools/bzl/js.bzl
@@ -1,4 +1,4 @@
-load("@io_bazel_rules_closure//closure:defs.bzl", "closure_js_binary", "closure_js_library")
+load("@npm_bazel_terser//:index.bzl", "terser_minified")
 load("//lib/js:npm.bzl", "NPM_SHA1S", "NPM_VERSIONS")
 
 NPMJS = "NPMJS"
@@ -439,7 +439,7 @@
     """Combine html, js, css files and optionally split into js and html bundles."""
     _bundle_rule(pkg = native.package_name(), *args, **kwargs)
 
-def polygerrit_plugin(name, app, srcs = [], deps = [], externs = [], assets = None, plugin_name = None, **kwargs):
+def polygerrit_plugin(name, app, srcs = [], deps = [], assets = None, plugin_name = None, **kwargs):
     """Bundles plugin dependencies for deployment.
 
     This rule bundles all Polymer elements and JS dependencies into .html and .js files.
@@ -449,7 +449,6 @@
     Args:
       name: String, rule name.
       app: String, the main or root source file.
-      externs: Fileset, external definitions that should not be bundled.
       assets: Fileset, additional files to be used by plugin in runtime, exported to "plugins/${name}/static".
       plugin_name: String, plugin name. ${name} is used if not provided.
     """
@@ -473,29 +472,15 @@
     else:
         js_srcs = srcs
 
-    closure_js_library(
-        name = name + "_closure_lib",
-        srcs = js_srcs + externs,
-        convention = "GOOGLE",
-        no_closure_library = True,
-        deps = [
-            "//lib/polymer_externs:polymer_closure",
-            "//polygerrit-ui/app/externs:plugin",
-        ],
+    native.filegroup(
+        name = name + "-src-fg",
+        srcs = js_srcs,
     )
 
-    closure_js_binary(
-        name = name + "_bin",
-        compilation_level = "WHITESPACE_ONLY",
-        defs = [
-            "--polymer_version=2",
-            "--language_out=ECMASCRIPT_2017",
-            "--rewrite_polyfills=false",
-        ],
-        deps = [
-            name + "_closure_lib",
-        ],
-        dependency_mode = "PRUNE_LEGACY",
+    terser_minified(
+        name = name + ".min",
+        sourcemap = False,
+        src = name + "-src-fg",
     )
 
     if html_plugin:
@@ -519,7 +504,7 @@
 
     native.genrule(
         name = name + "_rename_js",
-        srcs = [name + "_bin.js"],
+        srcs = [name + ".min"],
         outs = [plugin_name + ".js"],
         cmd = "cp $< $@",
         output_to_bindir = True,
diff --git a/yarn.lock b/yarn.lock
index 8e35c84..0c4383f 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -490,6 +490,11 @@
   resolved "https://registry.yarnpkg.com/@bazel/rollup/-/rollup-1.6.1.tgz#7ec9d39a3fca23256fca55410339724804802616"
   integrity sha512-FhblJkpd8VKl9txhAAIotSsIOHRpPd2FgJG7Op3uV7LfaCVBmUs3XDBZCgfwt5wmEpd3lwCHA1Ei+O/URS2+5w==
 
+"@bazel/terser@^1.7.0":
+  version "1.7.0"
+  resolved "https://registry.yarnpkg.com/@bazel/terser/-/terser-1.7.0.tgz#c43e711e13b9a71c7abd3ade04fb4650d547ad01"
+  integrity sha512-u/UXk0WUinvkk1g5xxfqGieBz3r12Bj2y2m25lC5GjHBgCpGk7DyeGGi9H3QQNO1Wmpw51QSE9gaPzKzjUVGug==
+
 "@bazel/typescript@^1.6.1":
   version "1.6.1"
   resolved "https://registry.yarnpkg.com/@bazel/typescript/-/typescript-1.6.1.tgz#1bf83c20021d359bc9b532181981ac540584a30c"
@@ -2705,7 +2710,7 @@
   resolved "https://registry.yarnpkg.com/commander/-/commander-2.17.1.tgz#bd77ab7de6de94205ceacc72f1716d29f20a77bf"
   integrity sha512-wPMUt6FnH2yzG95SA6mzjQOEKUU3aLaDEmzs1ti+1E9h+CsrZghRlqEM/EJ4KscsQVG8uNN4uVreUeT8+drlgg==
 
-commander@^2.19.0:
+commander@^2.19.0, commander@^2.20.0:
   version "2.20.3"
   resolved "https://registry.yarnpkg.com/commander/-/commander-2.20.3.tgz#fd485e84c03eb4881c20722ba48035e8531aeb33"
   integrity sha512-GpVkmM8vF2vQUkj2LvZmD35JxeJOLCwJ9cUkugyk2nuhbv3+mJvpLYYt+0+USMxE+oj+ey/lJEnhZw75x/OMcQ==
@@ -8641,6 +8646,14 @@
   dependencies:
     source-map "^0.5.6"
 
+source-map-support@~0.5.12:
+  version "0.5.19"
+  resolved "https://registry.yarnpkg.com/source-map-support/-/source-map-support-0.5.19.tgz#a98b62f86dcaf4f67399648c085291ab9e8fed61"
+  integrity sha512-Wonm7zOCIJzBGQdB+thsPar0kYuCIzYvxZwlBa87yi/Mdjv7Tip2cyVbLj5o0cFPN4EVkuTwb3GDDyUx2DGnGw==
+  dependencies:
+    buffer-from "^1.0.0"
+    source-map "^0.6.0"
+
 source-map-url@^0.4.0:
   version "0.4.0"
   resolved "https://registry.yarnpkg.com/source-map-url/-/source-map-url-0.4.0.tgz#3e935d7ddd73631b97659956d55128e87b5084a3"
@@ -9136,6 +9149,15 @@
     merge-stream "^1.0.0"
     through2 "^2.0.1"
 
+terser@^4.8.0:
+  version "4.8.0"
+  resolved "https://registry.yarnpkg.com/terser/-/terser-4.8.0.tgz#63056343d7c70bb29f3af665865a46fe03a0df17"
+  integrity sha512-EAPipTNeWsb/3wLPeup1tVPaXfIaU68xMnVdPafIL1TV05OhASArYyIfFvnvJCNrR2NIOvDVNNTFRa+Re2MWyw==
+  dependencies:
+    commander "^2.20.0"
+    source-map "~0.6.1"
+    source-map-support "~0.5.12"
+
 text-encoding@0.6.4:
   version "0.6.4"
   resolved "https://registry.yarnpkg.com/text-encoding/-/text-encoding-0.6.4.tgz#e399a982257a276dae428bb92845cb71bdc26d19"