diff --git a/Documentation/dev-crafting-changes.txt b/Documentation/dev-crafting-changes.txt
index 0f93be7..3440e85 100644
--- a/Documentation/dev-crafting-changes.txt
+++ b/Documentation/dev-crafting-changes.txt
@@ -210,15 +210,15 @@
     earlier in Gerrit's development.  To stay consistent, new ssh
     commands should follow this older pattern; but eventually these
     should get converted to eliminate this exception.
-  * Don't leave repository objects (git or schema) open.  A .close()
-    after every open should be placed in a finally{} block.
+  * Don't leave repository objects (git or schema) open.  Use a
+    try-with-resources statement to ensure that repository objects get
+    closed after use.
   * Don't leave UI components, which can cause new actions to occur,
     enabled during RPCs which update Git repositories, including NoteDb.
     This is to prevent people from submitting actions more than once
     when operating on slow links.  If the action buttons are disabled,
     they cannot be resubmitted and the user can see that Gerrit is still
     busy.
-  * ...and so is Guava (previously known as Google Collections).
 
 [[tests]]
 == Tests
diff --git a/WORKSPACE b/WORKSPACE
index 9901c1d..f160f64 100644
--- a/WORKSPACE
+++ b/WORKSPACE
@@ -749,8 +749,8 @@
 # Keep this version of Soy synchronized with the version used in Gitiles.
 maven_jar(
     name = "soy",
-    artifact = "com.google.template:soy:2019-03-11",
-    sha1 = "119ac4b3eb0e2c638526ca99374013965c727097",
+    artifact = "com.google.template:soy:2019-04-18",
+    sha1 = "5750208855562d74f29eee39ee497d5cf6df1490",
 )
 
 maven_jar(
diff --git a/java/com/google/gerrit/server/account/externalids/ExternalIdNotes.java b/java/com/google/gerrit/server/account/externalids/ExternalIdNotes.java
index eef2156..2c72f56 100644
--- a/java/com/google/gerrit/server/account/externalids/ExternalIdNotes.java
+++ b/java/com/google/gerrit/server/account/externalids/ExternalIdNotes.java
@@ -36,10 +36,13 @@
 import com.google.gerrit.reviewdb.client.Account;
 import com.google.gerrit.reviewdb.client.RefNames;
 import com.google.gerrit.server.account.AccountCache;
+import com.google.gerrit.server.account.AccountsUpdate;
 import com.google.gerrit.server.config.AllUsersName;
 import com.google.gerrit.server.git.meta.MetaDataUpdate;
 import com.google.gerrit.server.git.meta.VersionedMetaData;
 import com.google.gerrit.server.index.account.AccountIndexer;
+import com.google.gerrit.server.logging.CallerFinder;
+import com.google.gerrit.server.update.RetryHelper;
 import com.google.inject.Inject;
 import com.google.inject.Provider;
 import com.google.inject.Singleton;
@@ -265,6 +268,7 @@
   private final AllUsersName allUsersName;
   private final Counter0 updateCount;
   private final Repository repo;
+  private final CallerFinder callerFinder;
 
   private NoteMap noteMap;
   private ObjectId oldRev;
@@ -294,6 +298,19 @@
             new Description("Total number of external ID updates.").setRate().setUnit("updates"));
     this.allUsersName = requireNonNull(allUsersName, "allUsersRepo");
     this.repo = requireNonNull(allUsersRepo, "allUsersRepo");
+    this.callerFinder =
+        CallerFinder.builder()
+            // 1. callers that come through ExternalIds
+            .addTarget(ExternalIds.class)
+
+            // 2. callers that come through AccountsUpdate
+            .addTarget(AccountsUpdate.class)
+            .addIgnoredPackage("com.github.rholder.retry")
+            .addIgnoredClass(RetryHelper.class)
+
+            // 3. direct callers
+            .addTarget(ExternalIdNotes.class)
+            .build();
   }
 
   public ExternalIdNotes setAfterReadRevision(Runnable afterReadRevision) {
@@ -658,7 +675,7 @@
   @Override
   protected void onLoad() throws IOException, ConfigInvalidException {
     if (revision != null) {
-      logger.atFine().log("Reading external ID note map");
+      logger.atFine().log("Reading external ID note map (caller: %s)", callerFinder.findCaller());
       noteMap = NoteMap.read(reader, revision);
     } else {
       noteMap = NoteMap.newEmptyMap();
diff --git a/java/com/google/gerrit/server/logging/CallerFinder.java b/java/com/google/gerrit/server/logging/CallerFinder.java
index c27dbbb..73ffeb5 100644
--- a/java/com/google/gerrit/server/logging/CallerFinder.java
+++ b/java/com/google/gerrit/server/logging/CallerFinder.java
@@ -149,6 +149,20 @@
    */
   public abstract int skip();
 
+  /**
+   * Packages that should be ignored and not be considered as caller once a target has been found.
+   *
+   * @return the ignored packages
+   */
+  public abstract ImmutableList<String> ignoredPackages();
+
+  /**
+   * Classes that should be ignored and not be considered as caller once a target has been found.
+   *
+   * @return the qualified names of the ignored classes
+   */
+  public abstract ImmutableList<String> ignoredClasses();
+
   @AutoValue.Builder
   public abstract static class Builder {
     abstract ImmutableList.Builder<Class<?>> targetsBuilder();
@@ -164,6 +178,20 @@
 
     public abstract Builder skip(int skip);
 
+    abstract ImmutableList.Builder<String> ignoredPackagesBuilder();
+
+    public Builder addIgnoredPackage(String ignoredPackage) {
+      ignoredPackagesBuilder().add(ignoredPackage);
+      return this;
+    }
+
+    abstract ImmutableList.Builder<String> ignoredClassesBuilder();
+
+    public Builder addIgnoredClass(Class<?> ignoredClass) {
+      ignoredClassesBuilder().add(ignoredClass.getName());
+      return this;
+    }
+
     public abstract CallerFinder build();
   }
 
@@ -194,7 +222,9 @@
         StackTraceElement element = stack[index];
         if (isCaller(target, element.getClassName(), matchSubClasses())) {
           foundCaller = true;
-        } else if (foundCaller) {
+        } else if (foundCaller
+            && !ignoredPackages().contains(getPackageName(element))
+            && !ignoredClasses().contains(element.getClassName())) {
           return Optional.of(element.toString());
         }
       }
@@ -206,6 +236,11 @@
     }
   }
 
+  private static String getPackageName(StackTraceElement element) {
+    String className = element.getClassName();
+    return className.substring(0, className.lastIndexOf("."));
+  }
+
   private boolean isCaller(Class<?> target, String className, boolean matchSubClasses)
       throws ClassNotFoundException {
     if (matchSubClasses) {
diff --git a/java/com/google/gerrit/server/notedb/ChangeNotesParser.java b/java/com/google/gerrit/server/notedb/ChangeNotesParser.java
index 185f651..4fad58e 100644
--- a/java/com/google/gerrit/server/notedb/ChangeNotesParser.java
+++ b/java/com/google/gerrit/server/notedb/ChangeNotesParser.java
@@ -999,7 +999,8 @@
 
   private void updatePatchSetStates() {
     Set<PatchSet.Id> missing = new TreeSet<>(comparing(PatchSet.Id::get));
-    missing.addAll(patchSets.keySet());
+    patchSets.keySet().stream().filter(p -> !patchSetCommitParsed(p)).forEach(p -> missing.add(p));
+
     for (Map.Entry<PatchSet.Id, PatchSetState> e : patchSetStates.entrySet()) {
       switch (e.getValue()) {
         case PUBLISHED:
diff --git a/java/com/google/gerrit/server/notedb/RepoSequence.java b/java/com/google/gerrit/server/notedb/RepoSequence.java
index 1c33a68..4d96565 100644
--- a/java/com/google/gerrit/server/notedb/RepoSequence.java
+++ b/java/com/google/gerrit/server/notedb/RepoSequence.java
@@ -29,8 +29,10 @@
 import com.google.common.annotations.VisibleForTesting;
 import com.google.common.base.Throwables;
 import com.google.common.collect.ImmutableList;
+import com.google.common.collect.Iterables;
 import com.google.common.util.concurrent.Runnables;
 import com.google.gerrit.exceptions.StorageException;
+import com.google.gerrit.git.LockFailureException;
 import com.google.gerrit.git.RefUpdateUtil;
 import com.google.gerrit.reviewdb.client.Project;
 import com.google.gerrit.reviewdb.client.RefNames;
@@ -40,7 +42,6 @@
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Optional;
-import java.util.concurrent.Callable;
 import java.util.concurrent.ExecutionException;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.locks.Lock;
@@ -69,9 +70,12 @@
   }
 
   @VisibleForTesting
-  static RetryerBuilder<RefUpdate> retryerBuilder() {
-    return RetryerBuilder.<RefUpdate>newBuilder()
-        .retryIfResult(ru -> ru != null && RefUpdate.Result.LOCK_FAILURE.equals(ru.getResult()))
+  static RetryerBuilder<ImmutableList<Integer>> retryerBuilder() {
+    return RetryerBuilder.<ImmutableList<Integer>>newBuilder()
+        .retryIfException(
+            t ->
+                t instanceof StorageException
+                    && ((StorageException) t).getCause() instanceof LockFailureException)
         .withWaitStrategy(
             WaitStrategies.join(
                 WaitStrategies.exponentialWait(5, TimeUnit.SECONDS),
@@ -79,7 +83,7 @@
         .withStopStrategy(StopStrategies.stopAfterDelay(30, TimeUnit.SECONDS));
   }
 
-  private static final Retryer<RefUpdate> RETRYER = retryerBuilder().build();
+  private static final Retryer<ImmutableList<Integer>> RETRYER = retryerBuilder().build();
 
   private final GitRepositoryManager repoManager;
   private final GitReferenceUpdated gitRefUpdated;
@@ -89,7 +93,7 @@
   private final int floor;
   private final int batchSize;
   private final Runnable afterReadRef;
-  private final Retryer<RefUpdate> retryer;
+  private final Retryer<ImmutableList<Integer>> retryer;
 
   // Protects all non-final fields.
   private final Lock counterLock;
@@ -147,7 +151,7 @@
       Seed seed,
       int batchSize,
       Runnable afterReadRef,
-      Retryer<RefUpdate> retryer) {
+      Retryer<ImmutableList<Integer>> retryer) {
     this(repoManager, gitRefUpdated, projectName, name, seed, batchSize, afterReadRef, retryer, 0);
   }
 
@@ -159,7 +163,7 @@
       Seed seed,
       int batchSize,
       Runnable afterReadRef,
-      Retryer<RefUpdate> retryer,
+      Retryer<ImmutableList<Integer>> retryer,
       int floor) {
     this.repoManager = requireNonNull(repoManager, "repoManager");
     this.gitRefUpdated = requireNonNull(gitRefUpdated, "gitRefUpdated");
@@ -184,78 +188,85 @@
     counterLock = new ReentrantLock(true);
   }
 
+  /**
+   * Retrieves the next available sequence number.
+   *
+   * <p>This method is thread-safe.
+   *
+   * @return the next available sequence number
+   */
   public int next() {
-    counterLock.lock();
-    try {
-      if (counter >= limit) {
-        acquire(batchSize);
-      }
-      return counter++;
-    } finally {
-      counterLock.unlock();
-    }
+    return Iterables.getOnlyElement(next(1));
   }
 
+  /**
+   * Retrieves the next N available sequence number.
+   *
+   * <p>This method is thread-safe.
+   *
+   * @param count the number of sequence numbers which should be returned
+   * @return the next N available sequence numbers
+   */
   public ImmutableList<Integer> next(int count) {
     if (count == 0) {
       return ImmutableList.of();
     }
     checkArgument(count > 0, "count is negative: %s", count);
-    counterLock.lock();
-    try {
-      List<Integer> ids = new ArrayList<>(count);
-      while (counter < limit) {
-        ids.add(counter++);
-        if (ids.size() == count) {
-          return ImmutableList.copyOf(ids);
-        }
-      }
-      acquire(Math.max(count - ids.size(), batchSize));
-      while (ids.size() < count) {
-        ids.add(counter++);
-      }
-      return ImmutableList.copyOf(ids);
-    } finally {
-      counterLock.unlock();
-    }
-  }
 
-  private void acquire(int count) {
-    try (Repository repo = repoManager.openRepository(projectName);
-        RevWalk rw = new RevWalk(repo)) {
-      TryAcquire attempt = new TryAcquire(repo, rw, count);
-      RefUpdateUtil.checkResult(retryer.call(attempt));
-      counter = attempt.next;
-      limit = counter + count;
-      acquireCount++;
+    try {
+      return retryer.call(
+          () -> {
+            counterLock.lock();
+            try {
+              if (count == 1) {
+                if (counter >= limit) {
+                  acquire(batchSize);
+                }
+                return ImmutableList.of(counter++);
+              }
+
+              List<Integer> ids = new ArrayList<>(count);
+              while (counter < limit) {
+                ids.add(counter++);
+                if (ids.size() == count) {
+                  return ImmutableList.copyOf(ids);
+                }
+              }
+              acquire(Math.max(count - ids.size(), batchSize));
+              while (ids.size() < count) {
+                ids.add(counter++);
+              }
+              return ImmutableList.copyOf(ids);
+            } finally {
+              counterLock.unlock();
+            }
+          });
     } catch (ExecutionException | RetryException e) {
       if (e.getCause() != null) {
         Throwables.throwIfInstanceOf(e.getCause(), StorageException.class);
       }
       throw new StorageException(e);
-    } catch (IOException e) {
-      throw new StorageException(e);
     }
   }
 
-  private class TryAcquire implements Callable<RefUpdate> {
-    private final Repository repo;
-    private final RevWalk rw;
-    private final int count;
-
-    private int next;
-
-    private TryAcquire(Repository repo, RevWalk rw, int count) {
-      this.repo = repo;
-      this.rw = rw;
-      this.count = count;
-    }
-
-    @Override
-    public RefUpdate call() throws Exception {
+  /**
+   * Updates the next available sequence number in NoteDb in order to have a batch of sequence
+   * numbers available that can be handed out. {@link #counter} stores the next sequence number that
+   * can be handed out. When {@link #limit} is reached a new batch of sequence numbers needs to be
+   * retrieved by calling this method.
+   *
+   * <p><strong>Note:</strong> Callers are required to acquire the {@link #counterLock} before
+   * calling this method.
+   *
+   * @param count the number of sequence numbers which should be retrieved
+   */
+  private void acquire(int count) {
+    try (Repository repo = repoManager.openRepository(projectName);
+        RevWalk rw = new RevWalk(repo)) {
       Optional<IntBlob> blob = IntBlob.parse(repo, refName, rw);
       afterReadRef.run();
       ObjectId oldId;
+      int next;
       if (!blob.isPresent()) {
         oldId = ObjectId.zeroId();
         next = seed.get();
@@ -264,7 +275,14 @@
         next = blob.get().value();
       }
       next = Math.max(floor, next);
-      return IntBlob.tryStore(repo, rw, projectName, refName, oldId, next + count, gitRefUpdated);
+      RefUpdate refUpdate =
+          IntBlob.tryStore(repo, rw, projectName, refName, oldId, next + count, gitRefUpdated);
+      RefUpdateUtil.checkResult(refUpdate);
+      counter = next;
+      limit = counter + count;
+      acquireCount++;
+    } catch (IOException e) {
+      throw new StorageException(e);
     }
   }
 
diff --git a/javatests/com/google/gerrit/acceptance/api/accounts/AccountIT.java b/javatests/com/google/gerrit/acceptance/api/accounts/AccountIT.java
index 33fca19..f5954d9 100644
--- a/javatests/com/google/gerrit/acceptance/api/accounts/AccountIT.java
+++ b/javatests/com/google/gerrit/acceptance/api/accounts/AccountIT.java
@@ -1122,6 +1122,27 @@
   }
 
   @Test
+  @Sandboxed
+  public void deleteAllEmails() throws Exception {
+    EmailInput input = new EmailInput();
+    input.email = "foo.bar@example.com";
+    input.noConfirmation = true;
+    gApi.accounts().self().addEmail(input);
+
+    requestScopeOperations.resetCurrentApiUser();
+    Set<String> allEmails = getEmails();
+    assertThat(allEmails).hasSize(2);
+
+    for (String email : allEmails) {
+      gApi.accounts().self().deleteEmail(email);
+    }
+
+    requestScopeOperations.resetCurrentApiUser();
+    assertThat(getEmails()).isEmpty();
+    assertThat(gApi.accounts().self().get().email).isNull();
+  }
+
+  @Test
   public void deleteEmailFromCustomExternalIdSchemes() throws Exception {
     String email = "foo.bar@example.com";
     String extId1 = "foo:bar";
diff --git a/javatests/com/google/gerrit/server/notedb/RepoSequenceTest.java b/javatests/com/google/gerrit/server/notedb/RepoSequenceTest.java
index f088a79..6baa3e4 100644
--- a/javatests/com/google/gerrit/server/notedb/RepoSequenceTest.java
+++ b/javatests/com/google/gerrit/server/notedb/RepoSequenceTest.java
@@ -20,9 +20,12 @@
 import static java.nio.charset.StandardCharsets.UTF_8;
 import static org.eclipse.jgit.lib.Constants.OBJ_BLOB;
 
+import com.github.rholder.retry.BlockStrategy;
 import com.github.rholder.retry.Retryer;
 import com.github.rholder.retry.RetryerBuilder;
 import com.github.rholder.retry.StopStrategies;
+import com.google.common.collect.ImmutableList;
+import com.google.common.truth.Expect;
 import com.google.common.util.concurrent.Runnables;
 import com.google.gerrit.exceptions.StorageException;
 import com.google.gerrit.reviewdb.client.Project;
@@ -30,7 +33,9 @@
 import com.google.gerrit.server.extensions.events.GitReferenceUpdated;
 import com.google.gerrit.testing.InMemoryRepositoryManager;
 import java.io.IOException;
-import java.util.concurrent.ExecutionException;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.Executors;
+import java.util.concurrent.Future;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.atomic.AtomicInteger;
 import org.eclipse.jgit.errors.IncorrectObjectTypeException;
@@ -41,11 +46,14 @@
 import org.eclipse.jgit.lib.Repository;
 import org.eclipse.jgit.revwalk.RevWalk;
 import org.junit.Before;
+import org.junit.Rule;
 import org.junit.Test;
 
 public class RepoSequenceTest {
+  @Rule public final Expect expect = Expect.create();
+
   // Don't sleep in tests.
-  private static final Retryer<RefUpdate> RETRYER =
+  private static final Retryer<ImmutableList<Integer>> RETRYER =
       RepoSequence.retryerBuilder().withBlockStrategy(t -> {}).build();
 
   private InMemoryRepositoryManager repoManager;
@@ -160,7 +168,7 @@
     RepoSequence s = newSequence("id", 1, 10, bgUpdate, RETRYER);
     assertThat(doneBgUpdate.get()).isFalse();
     assertThat(s.next()).isEqualTo(1234);
-    // Single acquire call that results in 2 ref reads.
+    // Two acquire calls, but only one successful.
     assertThat(s.acquireCount).isEqualTo(1);
     assertThat(doneBgUpdate.get()).isTrue();
   }
@@ -182,8 +190,7 @@
       tr.branch(RefNames.REFS_SEQUENCES + "id").commit().create();
       StorageException e =
           assertThrows(StorageException.class, () -> newSequence("id", 1, 3).next());
-      assertThat(e.getCause()).isInstanceOf(ExecutionException.class);
-      assertThat(e.getCause().getCause()).isInstanceOf(IncorrectObjectTypeException.class);
+      assertThat(e.getCause()).isInstanceOf(IncorrectObjectTypeException.class);
     }
   }
 
@@ -196,7 +203,7 @@
             1,
             10,
             () -> writeBlob("id", Integer.toString(bgCounter.getAndAdd(1000))),
-            RetryerBuilder.<RefUpdate>newBuilder()
+            RetryerBuilder.<ImmutableList<Integer>>newBuilder()
                 .withStopStrategy(StopStrategies.stopAfterAttempt(3))
                 .build());
     StorageException thrown = assertThrows(StorageException.class, () -> s.next());
@@ -206,6 +213,77 @@
   }
 
   @Test
+  public void idCanBeRetrievedFromOtherThreadWhileWaitingToRetry() throws Exception {
+    // Seed existing ref value.
+    writeBlob("id", "1");
+
+    // Let the first update of the sequence fail with LOCK_FAILURE, so that the update is retried.
+    CountDownLatch lockFailure = new CountDownLatch(1);
+    CountDownLatch parallelSuccessfulSequenceGeneration = new CountDownLatch(1);
+    AtomicBoolean doneBgUpdate = new AtomicBoolean(false);
+    Runnable bgUpdate =
+        () -> {
+          if (!doneBgUpdate.getAndSet(true)) {
+            writeBlob("id", "1234");
+          }
+        };
+
+    BlockStrategy blockStrategy =
+        t -> {
+          // Keep blocking until we verified that another thread can retrieve a sequence number
+          // while we are blocking here.
+          lockFailure.countDown();
+          parallelSuccessfulSequenceGeneration.await();
+        };
+
+    // Use batch size = 1 to make each call go to NoteDb.
+    RepoSequence s =
+        newSequence(
+            "id",
+            1,
+            1,
+            bgUpdate,
+            RepoSequence.retryerBuilder().withBlockStrategy(blockStrategy).build());
+
+    assertThat(doneBgUpdate.get()).isFalse();
+
+    // Start a thread to get a sequence number. This thread needs to update the sequence in NoteDb,
+    // but due to the background update (see bgUpdate) the first attempt to update NoteDb fails
+    // with LOCK_FAILURE. RepoSequence uses a retryer to retry the NoteDb update on LOCK_FAILURE,
+    // but our block strategy ensures that this retry only happens after isBlocking was set to
+    // false.
+    Future<?> future =
+        Executors.newFixedThreadPool(1)
+            .submit(
+                () -> {
+                  // The background update sets the next available sequence number to 1234. Then the
+                  // test thread retrieves one sequence number, so that the next available sequence
+                  // number for this thread is 1235.
+                  expect.that(s.next()).isEqualTo(1235);
+                });
+
+    // Wait until the LOCK_FAILURE has happened and the block strategy was entered.
+    lockFailure.await();
+
+    // Verify that the background update was done now.
+    assertThat(doneBgUpdate.get()).isTrue();
+
+    // Verify that we can retrieve a sequence number while the other thread is blocked. If the
+    // s.next() call hangs it means that the RepoSequence.counterLock was not released before the
+    // background thread started to block for retry. In this case the test would time out.
+    assertThat(s.next()).isEqualTo(1234);
+
+    // Stop blocking the retry of the background thread (and verify that it was still blocked).
+    parallelSuccessfulSequenceGeneration.countDown();
+
+    // Wait until the background thread is done.
+    future.get();
+
+    // Two successful acquire calls (because batch size == 1).
+    assertThat(s.acquireCount).isEqualTo(2);
+  }
+
+  @Test
   public void nextWithCountOneCaller() throws Exception {
     RepoSequence s = newSequence("id", 1, 3);
     assertThat(s.next(2)).containsExactly(1, 2).inOrder();
@@ -260,7 +338,7 @@
       final int start,
       int batchSize,
       Runnable afterReadRef,
-      Retryer<RefUpdate> retryer) {
+      Retryer<ImmutableList<Integer>> retryer) {
     return new RepoSequence(
         repoManager,
         GitReferenceUpdated.DISABLED,
diff --git a/lib/guava.bzl b/lib/guava.bzl
index c36bf14..9f0ff32 100644
--- a/lib/guava.bzl
+++ b/lib/guava.bzl
@@ -1,5 +1,5 @@
-GUAVA_VERSION = "27.1-jre"
+GUAVA_VERSION = "28.0-jre"
 
-GUAVA_BIN_SHA1 = "e47b59c893079b87743cdcfb6f17ca95c08c592c"
+GUAVA_BIN_SHA1 = "54fed371b4b8a8cce1e94a9abd9620982d3aa54b"
 
 GUAVA_DOC_URL = "https://google.github.io/guava/releases/" + GUAVA_VERSION + "/api/docs/"
diff --git a/tools/bzl/js.bzl b/tools/bzl/js.bzl
index df9434d..188a2a1 100644
--- a/tools/bzl/js.bzl
+++ b/tools/bzl/js.bzl
@@ -45,6 +45,8 @@
     implementation = _npm_binary_impl,
 )
 
+ComponentInfo = provider()
+
 # for use in repo rules.
 def _run_npm_binary_str(ctx, tarball, args):
     python_bin = ctx.which("python")
@@ -133,31 +135,29 @@
 def _bower_component_impl(ctx):
     transitive_zipfiles = depset(
         direct = [ctx.file.zipfile],
-        transitive = [d.transitive_zipfiles for d in ctx.attr.deps],
+        transitive = [d[ComponentInfo].transitive_zipfiles for d in ctx.attr.deps],
     )
 
     transitive_licenses = depset(
         direct = [ctx.file.license],
-        transitive = [d.transitive_licenses for d in ctx.attr.deps],
+        transitive = [d[ComponentInfo].transitive_licenses for d in ctx.attr.deps],
     )
 
     transitive_versions = depset(
         direct = ctx.files.version_json,
-        transitive = [d.transitive_versions for d in ctx.attr.deps],
+        transitive = [d[ComponentInfo].transitive_versions for d in ctx.attr.deps],
     )
 
-    return struct(
-        transitive_licenses = transitive_licenses,
-        transitive_versions = transitive_versions,
-        transitive_zipfiles = transitive_zipfiles,
-    )
+    return [
+        ComponentInfo(
+            transitive_licenses = transitive_licenses,
+            transitive_versions = transitive_versions,
+            transitive_zipfiles = transitive_zipfiles,
+        ),
+    ]
 
 _common_attrs = {
-    "deps": attr.label_list(providers = [
-        "transitive_zipfiles",
-        "transitive_versions",
-        "transitive_licenses",
-    ]),
+    "deps": attr.label_list(providers = [ComponentInfo]),
 }
 
 def _js_component(ctx):
@@ -187,11 +187,13 @@
     if ctx.file.license:
         licenses.append(ctx.file.license)
 
-    return struct(
-        transitive_licenses = depset(licenses),
-        transitive_versions = depset(),
-        transitive_zipfiles = list([ctx.outputs.zip]),
-    )
+    return [
+        ComponentInfo(
+            transitive_licenses = depset(licenses),
+            transitive_versions = depset(),
+            transitive_zipfiles = list([ctx.outputs.zip]),
+        ),
+    ]
 
 js_component = rule(
     _js_component,
@@ -233,16 +235,16 @@
     """A bunch of bower components zipped up."""
     zips = depset()
     for d in ctx.attr.deps:
-        files = d.transitive_zipfiles
+        files = d[ComponentInfo].transitive_zipfiles
 
         # TODO(davido): Make sure the field always contains a depset
         if type(files) == "list":
             files = depset(files)
         zips = depset(transitive = [zips, files])
 
-    versions = depset(transitive = [d.transitive_versions for d in ctx.attr.deps])
+    versions = depset(transitive = [d[ComponentInfo].transitive_versions for d in ctx.attr.deps])
 
-    licenses = depset(transitive = [d.transitive_versions for d in ctx.attr.deps])
+    licenses = depset(transitive = [d[ComponentInfo].transitive_versions for d in ctx.attr.deps])
 
     out_zip = ctx.outputs.zip
     out_versions = ctx.outputs.version_json
@@ -272,11 +274,13 @@
         command = "(echo '{' ; for j in  %s ; do cat $j; echo ',' ; done ; echo \\\"\\\":\\\"\\\"; echo '}') > %s" % (" ".join([v.path for v in versions.to_list()]), out_versions.path),
     )
 
-    return struct(
-        transitive_licenses = licenses,
-        transitive_versions = versions,
-        transitive_zipfiles = zips,
-    )
+    return [
+        ComponentInfo(
+            transitive_licenses = licenses,
+            transitive_versions = versions,
+            transitive_zipfiles = zips,
+        ),
+    ]
 
 bower_component_bundle = rule(
     _bower_component_bundle_impl,
@@ -304,7 +308,7 @@
     else:
         bundled = ctx.outputs.html
     destdir = ctx.outputs.html.path + ".dir"
-    zips = [z for d in ctx.attr.deps for z in d.transitive_zipfiles.to_list()]
+    zips = [z for d in ctx.attr.deps for z in d[ComponentInfo].transitive_zipfiles.to_list()]
 
     # We are splitting off the package dir from the app.path such that
     # we can set the package dir as the root for the bundler, which means
@@ -412,7 +416,7 @@
         ),
         "pkg": attr.string(mandatory = True),
         "split": attr.bool(default = True),
-        "deps": attr.label_list(providers = ["transitive_zipfiles"]),
+        "deps": attr.label_list(providers = [ComponentInfo]),
         "_bundler_archive": attr.label(
             default = Label("@polymer-bundler//:%s" % _npm_tarball("polymer-bundler")),
             allow_single_file = True,