diff --git a/java/com/google/gerrit/plugins/codeowners/acceptance/testsuite/TestPathExpressions.java b/java/com/google/gerrit/plugins/codeowners/acceptance/testsuite/TestPathExpressions.java
index 91867cb..d2acaed 100644
--- a/java/com/google/gerrit/plugins/codeowners/acceptance/testsuite/TestPathExpressions.java
+++ b/java/com/google/gerrit/plugins/codeowners/acceptance/testsuite/TestPathExpressions.java
@@ -41,16 +41,20 @@
   }
 
   /**
-   * Creates a path expression that matches all files of the given file type in the current folder.
+   * Creates a path expression that matches all files of the given file type in the current folder
+   * and all subfolders.
    *
    * @param fileType the file type
    */
-  public String matchFileTypeInCurrentFolder(String fileType) {
+  public String matchFileType(String fileType) {
     PathExpressionMatcher pathExpressionMatcher = getPathExpressionMatcher();
-    if (pathExpressionMatcher instanceof GlobMatcher
-        || pathExpressionMatcher instanceof FindOwnersGlobMatcher
-        || pathExpressionMatcher instanceof SimplePathExpressionMatcher) {
+    if (pathExpressionMatcher instanceof GlobMatcher) {
+      return "**." + fileType;
+    } else if (pathExpressionMatcher instanceof FindOwnersGlobMatcher) {
       return "*." + fileType;
+    } else if (pathExpressionMatcher instanceof SimplePathExpressionMatcher) {
+      // '...' (matches any string, including slashes), followed by '.<file-type>'
+      return "...." + fileType;
     }
     throw new IllegalStateException(
         String.format(
diff --git a/java/com/google/gerrit/plugins/codeowners/backend/CodeOwnerApprovalCheck.java b/java/com/google/gerrit/plugins/codeowners/backend/CodeOwnerApprovalCheck.java
index 937a118..33fd2e4 100644
--- a/java/com/google/gerrit/plugins/codeowners/backend/CodeOwnerApprovalCheck.java
+++ b/java/com/google/gerrit/plugins/codeowners/backend/CodeOwnerApprovalCheck.java
@@ -47,6 +47,7 @@
 import com.google.gerrit.server.permissions.PermissionBackend;
 import com.google.gerrit.server.permissions.PermissionBackendException;
 import com.google.gerrit.server.permissions.ProjectPermission;
+import com.google.gerrit.server.util.LabelVote;
 import com.google.inject.Inject;
 import com.google.inject.Provider;
 import com.google.inject.Singleton;
@@ -222,7 +223,15 @@
           codeOwnersPluginConfiguration.getOverrideApproval(changeNotes.getProjectName());
       boolean hasOverride = hasOverride(overrideApprovals, changeNotes, patchSetUploader);
       logger.atFine().log(
-          "hasOverride = %s (overrideApprovals = %s)", hasOverride, overrideApprovals);
+          "hasOverride = %s (overrideApprovals = %s)",
+          hasOverride,
+          overrideApprovals.stream()
+              .map(
+                  overrideApproval ->
+                      String.format(
+                          "%s (ignoreSelfApproval = %s)",
+                          overrideApproval, overrideApproval.labelType().isIgnoreSelfApproval()))
+              .collect(toImmutableList()));
 
       BranchNameKey branch = changeNotes.getChange().getDest();
       ObjectId revision = getDestBranchRevision(changeNotes.getChange());
@@ -934,6 +943,9 @@
                                   .labelType()
                                   .getLabelId()
                                   .equals(approval.key().labelId()))) {
+                logger.atFine().log(
+                    "Filtered out self-override %s of patch set uploader",
+                    LabelVote.create(approval.label(), approval.value()));
                 return false;
               }
               return true;
diff --git a/java/com/google/gerrit/plugins/codeowners/backend/OnCodeOwnerApproval.java b/java/com/google/gerrit/plugins/codeowners/backend/OnCodeOwnerApproval.java
index e818163..dff2876 100644
--- a/java/com/google/gerrit/plugins/codeowners/backend/OnCodeOwnerApproval.java
+++ b/java/com/google/gerrit/plugins/codeowners/backend/OnCodeOwnerApproval.java
@@ -124,6 +124,18 @@
       return Optional.empty();
     }
 
+    if (isIgnoredDueToSelfApproval(user, patchSet, requiredApproval)) {
+      if (isCodeOwnerApprovalNewlyApplied(requiredApproval, oldApprovals, newVote)
+          || isCodeOwnerApprovalUpOrDowngraded(requiredApproval, oldApprovals, newVote)) {
+        return Optional.of(
+            String.format(
+                "The vote %s is ignored as code-owner approval since the label doesn't allow"
+                    + " self approval of the patch set uploader.",
+                newVote));
+      }
+      return Optional.empty();
+    }
+
     boolean hasImplicitApprovalByUser =
         codeOwnersPluginConfiguration.areImplicitApprovalsEnabled(changeNotes.getProjectName())
             && patchSet.uploader().equals(user.getAccountId());
@@ -222,6 +234,12 @@
     pathsToAppend.forEach(path -> message.append(String.format("* %s\n", JgitPath.of(path).get())));
   }
 
+  private boolean isIgnoredDueToSelfApproval(
+      IdentifiedUser user, PatchSet patchSet, RequiredApproval requiredApproval) {
+    return patchSet.uploader().equals(user.getAccountId())
+        && requiredApproval.labelType().isIgnoreSelfApproval();
+  }
+
   private boolean isCodeOwnerApprovalNewlyApplied(
       RequiredApproval requiredApproval, Map<String, Short> oldApprovals, LabelVote newVote) {
     String labelName = requiredApproval.labelType().getName();
diff --git a/java/com/google/gerrit/plugins/codeowners/backend/OnCodeOwnerOverride.java b/java/com/google/gerrit/plugins/codeowners/backend/OnCodeOwnerOverride.java
index df24fbb..c200ae0 100644
--- a/java/com/google/gerrit/plugins/codeowners/backend/OnCodeOwnerOverride.java
+++ b/java/com/google/gerrit/plugins/codeowners/backend/OnCodeOwnerOverride.java
@@ -98,6 +98,18 @@
       RequiredApproval overrideApproval) {
     LabelVote newVote = getNewVote(overrideApproval, approvals);
 
+    if (isIgnoredDueToSelfApproval(user, patchSet, overrideApproval)) {
+      if (isCodeOwnerOverrideNewlyApplied(overrideApproval, oldApprovals, newVote)
+          || isCodeOwnerOverrideUpOrDowngraded(overrideApproval, oldApprovals, newVote)) {
+        return Optional.of(
+            String.format(
+                "The vote %s is ignored as code-owner override since the label doesn't allow"
+                    + " self approval of the patch set uploader.",
+                newVote));
+      }
+      return Optional.empty();
+    }
+
     if (isCodeOwnerOverrideNewlyApplied(overrideApproval, oldApprovals, newVote)) {
       return Optional.of(
           String.format(
@@ -134,6 +146,12 @@
     return Optional.empty();
   }
 
+  private boolean isIgnoredDueToSelfApproval(
+      IdentifiedUser user, PatchSet patchSet, RequiredApproval requiredApproval) {
+    return patchSet.uploader().equals(user.getAccountId())
+        && requiredApproval.labelType().isIgnoreSelfApproval();
+  }
+
   private boolean isCodeOwnerOverrideNewlyApplied(
       RequiredApproval requiredApproval, Map<String, Short> oldApprovals, LabelVote newVote) {
     String labelName = requiredApproval.labelType().getName();
diff --git a/java/com/google/gerrit/plugins/codeowners/testing/CodeOwnerInfoSubject.java b/java/com/google/gerrit/plugins/codeowners/testing/CodeOwnerInfoSubject.java
index 29df00b..33a19aa 100644
--- a/java/com/google/gerrit/plugins/codeowners/testing/CodeOwnerInfoSubject.java
+++ b/java/com/google/gerrit/plugins/codeowners/testing/CodeOwnerInfoSubject.java
@@ -14,8 +14,6 @@
 
 package com.google.gerrit.plugins.codeowners.testing;
 
-import static com.google.common.truth.Truth.assertAbout;
-
 import com.google.common.truth.ComparableSubject;
 import com.google.common.truth.Correspondence;
 import com.google.common.truth.FailureMetadata;
@@ -23,9 +21,7 @@
 import com.google.common.truth.Subject;
 import com.google.gerrit.entities.Account;
 import com.google.gerrit.plugins.codeowners.api.CodeOwnerInfo;
-import com.google.gerrit.truth.ListSubject;
 import com.google.gerrit.truth.NullAwareCorrespondence;
-import java.util.List;
 
 /** {@link Subject} for doing assertions on {@link CodeOwnerInfo}s. */
 public class CodeOwnerInfoSubject extends Subject {
@@ -44,21 +40,6 @@
         codeOwnerInfo -> codeOwnerInfo.account.name, "has account name");
   }
 
-  /**
-   * Starts fluent chain to do assertions on a {@link CodeOwnerInfo}.
-   *
-   * @param codeOwnerInfo the code owner info on which assertions should be done
-   * @return the created {@link CodeOwnerInfoSubject}
-   */
-  public static CodeOwnerInfoSubject assertThat(CodeOwnerInfo codeOwnerInfo) {
-    return assertAbout(codeOwnerInfos()).that(codeOwnerInfo);
-  }
-
-  public static ListSubject<CodeOwnerInfoSubject, CodeOwnerInfo> assertThatList(
-      List<CodeOwnerInfo> codeOwnerInfos) {
-    return ListSubject.assertThat(codeOwnerInfos, codeOwnerInfos());
-  }
-
   public static Factory<CodeOwnerInfoSubject, CodeOwnerInfo> codeOwnerInfos() {
     return CodeOwnerInfoSubject::new;
   }
diff --git a/java/com/google/gerrit/plugins/codeowners/testing/CodeOwnerSubject.java b/java/com/google/gerrit/plugins/codeowners/testing/CodeOwnerSubject.java
index 49852bb..5e46c2c 100644
--- a/java/com/google/gerrit/plugins/codeowners/testing/CodeOwnerSubject.java
+++ b/java/com/google/gerrit/plugins/codeowners/testing/CodeOwnerSubject.java
@@ -14,32 +14,19 @@
 
 package com.google.gerrit.plugins.codeowners.testing;
 
-import static com.google.common.collect.ImmutableList.toImmutableList;
 import static com.google.common.truth.Truth.assertAbout;
 
 import com.google.common.truth.ComparableSubject;
-import com.google.common.truth.Correspondence;
 import com.google.common.truth.FailureMetadata;
 import com.google.common.truth.Subject;
 import com.google.gerrit.entities.Account;
 import com.google.gerrit.plugins.codeowners.backend.CodeOwner;
-import com.google.gerrit.truth.ListSubject;
-import com.google.gerrit.truth.NullAwareCorrespondence;
 import com.google.gerrit.truth.OptionalSubject;
 import java.util.Optional;
-import java.util.stream.Stream;
 
 /** {@link Subject} for doing assertions on {@link CodeOwner}s. */
 public class CodeOwnerSubject extends Subject {
   /**
-   * Constructs a {@link Correspondence} that maps {@link CodeOwner}s to {@link
-   * com.google.gerrit.entities.Account.Id}s.
-   */
-  public static final Correspondence<CodeOwner, Account.Id> hasAccountId() {
-    return NullAwareCorrespondence.transforming(CodeOwner::accountId, "has account ID");
-  }
-
-  /**
    * Starts fluent chain to do assertions on a {@link CodeOwner}.
    *
    * @param codeOwner the code owner on which assertions should be done
@@ -60,16 +47,6 @@
     return OptionalSubject.assertThat(codeOwner, codeOwners());
   }
 
-  /**
-   * Starts fluent chain to do assertions on a stream of {@link CodeOwner}s.
-   *
-   * @param codeOwners stream of code owners on which assertions should be done
-   * @return the created {@link ListSubject}
-   */
-  public static ListSubject<CodeOwnerSubject, CodeOwner> assertThat(Stream<CodeOwner> codeOwners) {
-    return ListSubject.assertThat(codeOwners.collect(toImmutableList()), codeOwners());
-  }
-
   /** Creates subject factory for mapping {@link CodeOwner}s to {@link CodeOwnerSubject}s. */
   private static Subject.Factory<CodeOwnerSubject, CodeOwner> codeOwners() {
     return CodeOwnerSubject::new;
diff --git a/java/com/google/gerrit/plugins/codeowners/testing/OptionalResultWithMessagesSubject.java b/java/com/google/gerrit/plugins/codeowners/testing/OptionalResultWithMessagesSubject.java
index a0a9082..8d46152 100644
--- a/java/com/google/gerrit/plugins/codeowners/testing/OptionalResultWithMessagesSubject.java
+++ b/java/com/google/gerrit/plugins/codeowners/testing/OptionalResultWithMessagesSubject.java
@@ -53,10 +53,6 @@
     this.optionalResultWithMessages = optionalResultWithMessages;
   }
 
-  public void isPresent() {
-    check("result()").about(optionals()).that(optionalResultWithMessages().result()).isPresent();
-  }
-
   public void isEmpty() {
     check("result()").about(optionals()).that(optionalResultWithMessages().result()).isEmpty();
   }
diff --git a/java/com/google/gerrit/plugins/codeowners/testing/PathCodeOwnerStatusSubject.java b/java/com/google/gerrit/plugins/codeowners/testing/PathCodeOwnerStatusSubject.java
index a99c0e6..5e2f58c 100644
--- a/java/com/google/gerrit/plugins/codeowners/testing/PathCodeOwnerStatusSubject.java
+++ b/java/com/google/gerrit/plugins/codeowners/testing/PathCodeOwnerStatusSubject.java
@@ -15,7 +15,6 @@
 package com.google.gerrit.plugins.codeowners.testing;
 
 import static com.google.common.truth.PathSubject.paths;
-import static com.google.common.truth.Truth.assertAbout;
 
 import com.google.common.truth.ComparableSubject;
 import com.google.common.truth.FailureMetadata;
@@ -27,16 +26,6 @@
 /** {@link Subject} for doing assertions on {@link PathCodeOwnerStatus}s. */
 public class PathCodeOwnerStatusSubject extends Subject {
   /**
-   * Starts fluent chain to do assertions on a {@link PathCodeOwnerStatus}.
-   *
-   * @param pathCodeOwnerStatus the {@link PathCodeOwnerStatus} on which assertions should be done
-   * @return the created {@link PathCodeOwnerStatusSubject}
-   */
-  public static PathCodeOwnerStatusSubject assertThat(PathCodeOwnerStatus pathCodeOwnerStatus) {
-    return assertAbout(pathCodeOwnerStatuses()).that(pathCodeOwnerStatus);
-  }
-
-  /**
    * Creates subject factory for mapping {@link PathCodeOwnerStatus}es to {@link
    * PathCodeOwnerStatusSubject}s.
    */
diff --git a/java/com/google/gerrit/plugins/codeowners/testing/RequiredApprovalSubject.java b/java/com/google/gerrit/plugins/codeowners/testing/RequiredApprovalSubject.java
index e869632..9e17d9a 100644
--- a/java/com/google/gerrit/plugins/codeowners/testing/RequiredApprovalSubject.java
+++ b/java/com/google/gerrit/plugins/codeowners/testing/RequiredApprovalSubject.java
@@ -24,8 +24,6 @@
 import com.google.common.truth.Subject;
 import com.google.gerrit.plugins.codeowners.backend.config.RequiredApproval;
 import com.google.gerrit.truth.ListSubject;
-import com.google.gerrit.truth.OptionalSubject;
-import java.util.Optional;
 
 /** {@link Subject} for doing assertions on {@link RequiredApproval}s. */
 public class RequiredApprovalSubject extends Subject {
@@ -40,17 +38,6 @@
   }
 
   /**
-   * Starts a fluent chain to do assertions on an {@link Optional} {@link RequiredApproval}.
-   *
-   * @param requiredApproval optional required approval on which assertions should be done
-   * @return the created {@link OptionalSubject}
-   */
-  public static OptionalSubject<RequiredApprovalSubject, RequiredApproval> assertThat(
-      Optional<RequiredApproval> requiredApproval) {
-    return OptionalSubject.assertThat(requiredApproval, requiredApprovals());
-  }
-
-  /**
    * Starts a fluent chain to do assertions on a list of {@link RequiredApproval}s.
    *
    * @param requiredApprovals list of required approvals on which assertions should be done
diff --git a/java/com/google/gerrit/plugins/codeowners/testing/SubmitRecordSubject.java b/java/com/google/gerrit/plugins/codeowners/testing/SubmitRecordSubject.java
index 301fc1d..7b45e8b 100644
--- a/java/com/google/gerrit/plugins/codeowners/testing/SubmitRecordSubject.java
+++ b/java/com/google/gerrit/plugins/codeowners/testing/SubmitRecordSubject.java
@@ -14,7 +14,6 @@
 
 package com.google.gerrit.plugins.codeowners.testing;
 
-import static com.google.common.truth.Truth.assertAbout;
 import static com.google.gerrit.plugins.codeowners.testing.SubmitRequirementSubject.submitRecordRequirements;
 import static com.google.gerrit.truth.ListSubject.elements;
 
@@ -30,16 +29,6 @@
 /** {@link Subject} for doing assertions on {@link SubmitRecord}s. */
 public class SubmitRecordSubject extends Subject {
   /**
-   * Starts fluent chain to do assertions on a {@link SubmitRecord}.
-   *
-   * @param submitRecord the {@link SubmitRecord} on which assertions should be done
-   * @return the created {@link SubmitRecordSubject}
-   */
-  public static SubmitRecordSubject assertThat(SubmitRecord submitRecord) {
-    return assertAbout(submitRecords()).that(submitRecord);
-  }
-
-  /**
    * Starts fluent chain to do assertions on an {@link Optional} {@link SubmitRecord}.
    *
    * @param submitRecord the {@link SubmitRecord} {@link Optional} on which assertions should be
diff --git a/javatests/com/google/gerrit/plugins/codeowners/acceptance/api/AbstractGetCodeOwnersForPathIT.java b/javatests/com/google/gerrit/plugins/codeowners/acceptance/api/AbstractGetCodeOwnersForPathIT.java
index d7d3da3..0826b9e 100644
--- a/javatests/com/google/gerrit/plugins/codeowners/acceptance/api/AbstractGetCodeOwnersForPathIT.java
+++ b/javatests/com/google/gerrit/plugins/codeowners/acceptance/api/AbstractGetCodeOwnersForPathIT.java
@@ -226,12 +226,12 @@
         .folderPath("/foo/bar/")
         .addCodeOwnerSet(
             CodeOwnerSet.builder()
-                .addPathExpression(testPathExpressions.matchFileTypeInCurrentFolder("txt"))
+                .addPathExpression(testPathExpressions.matchFileType("txt"))
                 .addCodeOwnerEmail(admin.email())
                 .build())
         .addCodeOwnerSet(
             CodeOwnerSet.builder()
-                .addPathExpression(testPathExpressions.matchFileTypeInCurrentFolder("md"))
+                .addPathExpression(testPathExpressions.matchFileType("md"))
                 .addCodeOwnerEmail(user.email())
                 .build())
         .create();
diff --git a/javatests/com/google/gerrit/plugins/codeowners/acceptance/api/OnCodeOwnerApprovalIT.java b/javatests/com/google/gerrit/plugins/codeowners/acceptance/api/OnCodeOwnerApprovalIT.java
index 97f426a..415dcc6 100644
--- a/javatests/com/google/gerrit/plugins/codeowners/acceptance/api/OnCodeOwnerApprovalIT.java
+++ b/javatests/com/google/gerrit/plugins/codeowners/acceptance/api/OnCodeOwnerApprovalIT.java
@@ -37,9 +37,7 @@
 import java.util.regex.Pattern;
 import org.junit.Test;
 
-/**
- * Acceptance test for {@code com.google.gerrit.plugins.codeowners.backend.OnCodeOwnerApproval}.
- */
+/** Acceptance test for {@code com.google.gerrit.plugins.codeowners.backend.OnCodeOwnerApproval}. */
 public class OnCodeOwnerApprovalIT extends AbstractCodeOwnersIT {
   @Inject private RequestScopeOperations requestScopeOperations;
   @Inject private ProjectOperations projectOperations;
@@ -947,4 +945,115 @@
     Collection<ChangeMessageInfo> messages = gApi.changes().id(changeId).get().messages;
     assertThat(Iterables.getLast(messages).message).isEqualTo("Patch Set 1: Code-Review+1");
   }
+
+  @Test
+  public void changeMessageExtendedIfCodeOwnerApprovalIsIgnoredDueToSelfApproval()
+      throws Exception {
+    LabelDefinitionInput input = new LabelDefinitionInput();
+    input.ignoreSelfApproval = true;
+    gApi.projects().name(allProjects.get()).label("Code-Review").update(input);
+
+    String changeId = createChange().getChangeId();
+
+    recommend(changeId);
+
+    Collection<ChangeMessageInfo> messages = gApi.changes().id(changeId).get().messages;
+    assertThat(Iterables.getLast(messages).message)
+        .isEqualTo(
+            "Patch Set 1: Code-Review+1\n\n"
+                + "The vote Code-Review+1 is ignored as code-owner approval since the label"
+                + " doesn't allow self approval of the patch set uploader.\n");
+  }
+
+  @Test
+  public void changeMessageExtendedIfUpgradedCodeOwnerApprovalIsIgnoredDueToSelfApproval()
+      throws Exception {
+    LabelDefinitionInput input = new LabelDefinitionInput();
+    input.ignoreSelfApproval = true;
+    gApi.projects().name(allProjects.get()).label("Code-Review").update(input);
+
+    String changeId = createChange().getChangeId();
+
+    recommend(changeId);
+
+    // Upgrade the approval from Code-Review+1 to Code-Review+2
+    approve(changeId);
+
+    Collection<ChangeMessageInfo> messages = gApi.changes().id(changeId).get().messages;
+    assertThat(Iterables.getLast(messages).message)
+        .isEqualTo(
+            "Patch Set 1: Code-Review+2\n\n"
+                + "The vote Code-Review+2 is ignored as code-owner approval since the label"
+                + " doesn't allow self approval of the patch set uploader.\n");
+  }
+
+  @Test
+  public void changeMessageExtendedIfDowngradedCodeOwnerApprovalIsIgnoredDueToSelfApproval()
+      throws Exception {
+    LabelDefinitionInput input = new LabelDefinitionInput();
+    input.ignoreSelfApproval = true;
+    gApi.projects().name(allProjects.get()).label("Code-Review").update(input);
+
+    String changeId = createChange().getChangeId();
+
+    approve(changeId);
+
+    // Downgrade the approval from Code-Review+2 to Code-Review+1
+    recommend(changeId);
+
+    Collection<ChangeMessageInfo> messages = gApi.changes().id(changeId).get().messages;
+    assertThat(Iterables.getLast(messages).message)
+        .isEqualTo(
+            "Patch Set 1: Code-Review+1\n\n"
+                + "The vote Code-Review+1 is ignored as code-owner approval since the label"
+                + " doesn't allow self approval of the patch set uploader.\n");
+  }
+
+  @Test
+  public void changeMessageNotExtendedIfIgnoredCodeOwnerApprovalIsRemoved() throws Exception {
+    LabelDefinitionInput input = new LabelDefinitionInput();
+    input.ignoreSelfApproval = true;
+    gApi.projects().name(allProjects.get()).label("Code-Review").update(input);
+
+    String changeId = createChange().getChangeId();
+
+    recommend(changeId);
+
+    // Remove the code-owner approval
+    gApi.changes().id(changeId).current().review(new ReviewInput().label("Code-Review", 0));
+
+    Collection<ChangeMessageInfo> messages = gApi.changes().id(changeId).get().messages;
+    assertThat(Iterables.getLast(messages).message).isEqualTo("Patch Set 1: -Code-Review");
+  }
+
+  @Test
+  public void changeMessageExtendedIfNonSelfApprovalCodeOwnerApprovalIsApplied() throws Exception {
+    codeOwnerConfigOperations
+        .newCodeOwnerConfig()
+        .project(project)
+        .branch("master")
+        .folderPath("/foo/")
+        .addCodeOwnerEmail(user.email())
+        .create();
+
+    LabelDefinitionInput input = new LabelDefinitionInput();
+    input.ignoreSelfApproval = true;
+    gApi.projects().name(allProjects.get()).label("Code-Review").update(input);
+
+    String path = "foo/bar.baz";
+    String changeId = createChange("Test Change", path, "file content").getChangeId();
+
+    requestScopeOperations.setApiUser(user.id());
+    recommend(changeId);
+
+    Collection<ChangeMessageInfo> messages = gApi.changes().id(changeId).get().messages;
+    assertThat(Iterables.getLast(messages).message)
+        .isEqualTo(
+            String.format(
+                "Patch Set 1: Code-Review+1\n\n"
+                    + "By voting Code-Review+1 the following files are now code-owner approved by"
+                    + " %s:\n"
+                    + "* %s\n",
+                user.fullName(), path));
+  }
 }
diff --git a/javatests/com/google/gerrit/plugins/codeowners/acceptance/api/OnCodeOwnerOverrrideIT.java b/javatests/com/google/gerrit/plugins/codeowners/acceptance/api/OnCodeOwnerOverrrideIT.java
index f094f7b..1628c03 100644
--- a/javatests/com/google/gerrit/plugins/codeowners/acceptance/api/OnCodeOwnerOverrrideIT.java
+++ b/javatests/com/google/gerrit/plugins/codeowners/acceptance/api/OnCodeOwnerOverrrideIT.java
@@ -434,4 +434,174 @@
                     + "* %s\n",
                 admin.fullName(), path));
   }
+
+  @Test
+  @GerritConfig(name = "plugin.code-owners.overrideApproval", value = "Owners-Override+1")
+  public void changeMessageExtendedIfCodeOwnerOverrideIsIgnoredDueToSelfApproval()
+      throws Exception {
+    LabelDefinitionInput input = new LabelDefinitionInput();
+    input.values = ImmutableMap.of("+1", "Override", " 0", "No Override");
+    input.ignoreSelfApproval = true;
+    gApi.projects().name(project.get()).label("Owners-Override").create(input);
+
+    // Allow to vote on the Owners-Override label.
+    projectOperations
+        .project(project)
+        .forUpdate()
+        .add(
+            TestProjectUpdate.allowLabel("Owners-Override")
+                .range(0, 1)
+                .ref("refs/*")
+                .group(REGISTERED_USERS)
+                .build())
+        .update();
+
+    String changeId = createChange().getChangeId();
+
+    gApi.changes().id(changeId).current().review(new ReviewInput().label("Owners-Override", 1));
+
+    Collection<ChangeMessageInfo> messages = gApi.changes().id(changeId).get().messages;
+    assertThat(Iterables.getLast(messages).message)
+        .isEqualTo(
+            "Patch Set 1: Owners-Override+1\n\n"
+                + "The vote Owners-Override+1 is ignored as code-owner override since the label"
+                + " doesn't allow self approval of the patch set uploader.\n");
+  }
+
+  @Test
+  @GerritConfig(name = "plugin.code-owners.overrideApproval", value = "Owners-Override+1")
+  public void changeMessageExtendedIfUpgradedCodeOwnerOverrideIsIgnoredDueToSelfApproval()
+      throws Exception {
+    LabelDefinitionInput input = new LabelDefinitionInput();
+    input.values = ImmutableMap.of("+2", "Override", "+1", "Override", " 0", "No Override");
+    input.ignoreSelfApproval = true;
+    gApi.projects().name(project.get()).label("Owners-Override").create(input);
+
+    // Allow to vote on the Owners-Override label.
+    projectOperations
+        .project(project)
+        .forUpdate()
+        .add(
+            TestProjectUpdate.allowLabel("Owners-Override")
+                .range(0, 2)
+                .ref("refs/*")
+                .group(REGISTERED_USERS)
+                .build())
+        .update();
+
+    String changeId = createChange().getChangeId();
+
+    gApi.changes().id(changeId).current().review(new ReviewInput().label("Owners-Override", 1));
+
+    // Upgrade the approval from Owners-Override+1 to Owners-Override+2
+    gApi.changes().id(changeId).current().review(new ReviewInput().label("Owners-Override", 2));
+
+    Collection<ChangeMessageInfo> messages = gApi.changes().id(changeId).get().messages;
+    assertThat(Iterables.getLast(messages).message)
+        .isEqualTo(
+            "Patch Set 1: Owners-Override+2\n\n"
+                + "The vote Owners-Override+2 is ignored as code-owner override since the label"
+                + " doesn't allow self approval of the patch set uploader.\n");
+  }
+
+  @Test
+  @GerritConfig(name = "plugin.code-owners.overrideApproval", value = "Owners-Override+1")
+  public void changeMessageExtendedIfDowngradedCodeOwnerOverrideIsIgnoredDueToSelfApproval()
+      throws Exception {
+    LabelDefinitionInput input = new LabelDefinitionInput();
+    input.values = ImmutableMap.of("+2", "Override", "+1", "Override", " 0", "No Override");
+    input.ignoreSelfApproval = true;
+    gApi.projects().name(project.get()).label("Owners-Override").create(input);
+
+    // Allow to vote on the Owners-Override label.
+    projectOperations
+        .project(project)
+        .forUpdate()
+        .add(
+            TestProjectUpdate.allowLabel("Owners-Override")
+                .range(0, 2)
+                .ref("refs/*")
+                .group(REGISTERED_USERS)
+                .build())
+        .update();
+
+    String changeId = createChange().getChangeId();
+
+    gApi.changes().id(changeId).current().review(new ReviewInput().label("Owners-Override", 2));
+
+    // Downgrade the approval from Owners-Override+2 to Owners-Override+1
+    gApi.changes().id(changeId).current().review(new ReviewInput().label("Owners-Override", 1));
+
+    Collection<ChangeMessageInfo> messages = gApi.changes().id(changeId).get().messages;
+    assertThat(Iterables.getLast(messages).message)
+        .isEqualTo(
+            "Patch Set 1: Owners-Override+1\n\n"
+                + "The vote Owners-Override+1 is ignored as code-owner override since the label"
+                + " doesn't allow self approval of the patch set uploader.\n");
+  }
+
+  @Test
+  @GerritConfig(name = "plugin.code-owners.overrideApproval", value = "Owners-Override+1")
+  public void changeMessageNotExtendedIfIgnoredCodeOwnerOverrideIsRemoved() throws Exception {
+    LabelDefinitionInput input = new LabelDefinitionInput();
+    input.values = ImmutableMap.of("+1", "Override", " 0", "No Override");
+    input.ignoreSelfApproval = true;
+    gApi.projects().name(project.get()).label("Owners-Override").create(input);
+
+    // Allow to vote on the Owners-Override label.
+    projectOperations
+        .project(project)
+        .forUpdate()
+        .add(
+            TestProjectUpdate.allowLabel("Owners-Override")
+                .range(0, 1)
+                .ref("refs/*")
+                .group(REGISTERED_USERS)
+                .build())
+        .update();
+
+    String changeId = createChange().getChangeId();
+
+    gApi.changes().id(changeId).current().review(new ReviewInput().label("Owners-Override", 1));
+
+    // Remove the override approval
+    gApi.changes().id(changeId).current().review(new ReviewInput().label("Owners-Override", 0));
+
+    Collection<ChangeMessageInfo> messages = gApi.changes().id(changeId).get().messages;
+    assertThat(Iterables.getLast(messages).message).isEqualTo("Patch Set 1: -Owners-Override");
+  }
+
+  @Test
+  @GerritConfig(name = "plugin.code-owners.overrideApproval", value = "Owners-Override+1")
+  public void changeMessageExtendedIfNonSelfApprovalCodeOwnerOverrideIsApplied() throws Exception {
+    LabelDefinitionInput input = new LabelDefinitionInput();
+    input.values = ImmutableMap.of("+1", "Override", " 0", "No Override");
+    input.ignoreSelfApproval = true;
+    gApi.projects().name(project.get()).label("Owners-Override").create(input);
+
+    // Allow to vote on the Owners-Override label.
+    projectOperations
+        .project(project)
+        .forUpdate()
+        .add(
+            TestProjectUpdate.allowLabel("Owners-Override")
+                .range(0, 1)
+                .ref("refs/*")
+                .group(REGISTERED_USERS)
+                .build())
+        .update();
+
+    String changeId = createChange().getChangeId();
+
+    requestScopeOperations.setApiUser(user.id());
+    gApi.changes().id(changeId).current().review(new ReviewInput().label("Owners-Override", 1));
+
+    Collection<ChangeMessageInfo> messages = gApi.changes().id(changeId).get().messages;
+    assertThat(Iterables.getLast(messages).message)
+        .isEqualTo(
+            String.format(
+                "Patch Set 1: Owners-Override+1\n\n"
+                    + "By voting Owners-Override+1 the code-owners submit requirement is overridden by %s\n",
+                user.fullName()));
+  }
 }
diff --git a/javatests/com/google/gerrit/plugins/codeowners/acceptance/testsuite/TestPathExpressionsTest.java b/javatests/com/google/gerrit/plugins/codeowners/acceptance/testsuite/TestPathExpressionsTest.java
new file mode 100644
index 0000000..0557da3
--- /dev/null
+++ b/javatests/com/google/gerrit/plugins/codeowners/acceptance/testsuite/TestPathExpressionsTest.java
@@ -0,0 +1,225 @@
+// Copyright (C) 2021 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.
+
+package com.google.gerrit.plugins.codeowners.acceptance.testsuite;
+
+import static com.google.common.truth.Truth.assertThat;
+import static com.google.gerrit.testing.GerritJUnit.assertThrows;
+
+import com.google.gerrit.acceptance.config.GerritConfig;
+import com.google.gerrit.entities.Project.NameKey;
+import com.google.gerrit.extensions.registration.DynamicMap;
+import com.google.gerrit.extensions.registration.PrivateInternals_DynamicMapImpl;
+import com.google.gerrit.extensions.registration.RegistrationHandle;
+import com.google.gerrit.plugins.codeowners.acceptance.AbstractCodeOwnersTest;
+import com.google.gerrit.plugins.codeowners.backend.CodeOwnerBackend;
+import com.google.gerrit.plugins.codeowners.backend.CodeOwnerConfig;
+import com.google.gerrit.plugins.codeowners.backend.CodeOwnerConfigUpdate;
+import com.google.gerrit.plugins.codeowners.backend.GlobMatcher;
+import com.google.gerrit.plugins.codeowners.backend.PathExpressionMatcher;
+import com.google.gerrit.server.IdentifiedUser;
+import com.google.inject.Key;
+import com.google.inject.util.Providers;
+import java.nio.file.Path;
+import java.util.Optional;
+import javax.annotation.Nullable;
+import org.eclipse.jgit.lib.ObjectId;
+import org.eclipse.jgit.revwalk.RevWalk;
+import org.junit.Before;
+import org.junit.Test;
+
+/** Tests for {@link TestPathExpressions}. */
+public class TestPathExpressionsTest extends AbstractCodeOwnersTest {
+  private TestPathExpressions testPathExpressions;
+  private DynamicMap<CodeOwnerBackend> codeOwnerBackends;
+
+  @Before
+  public void setUp() {
+    testPathExpressions = plugin.getSysInjector().getInstance(TestPathExpressions.class);
+    codeOwnerBackends =
+        plugin.getSysInjector().getInstance(new Key<DynamicMap<CodeOwnerBackend>>() {});
+  }
+
+  @Test
+  @GerritConfig(name = "plugin.code-owners.backend", value = "find-owners")
+  public void matchFileType_findOwnersBackend() throws Exception {
+    assertThat(testPathExpressions.matchFileType("md")).isEqualTo("*.md");
+  }
+
+  @Test
+  @GerritConfig(name = "plugin.code-owners.backend", value = "proto")
+  public void matchFileType_protoBackend() throws Exception {
+    assertThat(testPathExpressions.matchFileType("md")).isEqualTo("....md");
+  }
+
+  @Test
+  @GerritConfig(name = "plugin.code-owners.backend", value = TestCodeOwnerBackend.ID)
+  public void matchFileType_backendWithGlobMatcher() throws Exception {
+    try (AutoCloseable registration = registerTestBackend(GlobMatcher.INSTANCE)) {
+      assertThat(testPathExpressions.matchFileType("md")).isEqualTo("**.md");
+    }
+  }
+
+  @Test
+  @GerritConfig(name = "plugin.code-owners.backend", value = TestCodeOwnerBackend.ID)
+  public void matchFileType_backendWithUnknownMatcher() throws Exception {
+    PathExpressionMatcher pathExpressionMatcher =
+        new PathExpressionMatcher() {
+          @Override
+          public boolean matches(String pathExpression, Path relativePath) {
+            return false;
+          }
+        };
+    try (AutoCloseable registration = registerTestBackend(pathExpressionMatcher)) {
+      IllegalStateException exception =
+          assertThrows(IllegalStateException.class, () -> testPathExpressions.matchFileType("md"));
+      assertThat(exception)
+          .hasMessageThat()
+          .isEqualTo(
+              String.format(
+                  "path expression matcher %s not supported",
+                  pathExpressionMatcher.getClass().getName()));
+    }
+  }
+
+  @Test
+  @GerritConfig(name = "plugin.code-owners.backend", value = TestCodeOwnerBackend.ID)
+  public void matchFileType_backendWithoutMatcher() throws Exception {
+    TestCodeOwnerBackend testCodeOwnerBackend =
+        new TestCodeOwnerBackend(/* pathExpressionMatcher= */ null);
+    try (AutoCloseable registration = registerTestBackend(testCodeOwnerBackend)) {
+      IllegalStateException exception =
+          assertThrows(IllegalStateException.class, () -> testPathExpressions.matchFileType("md"));
+      assertThat(exception)
+          .hasMessageThat()
+          .isEqualTo(
+              String.format(
+                  "code owner backend %s doesn't support path expressions",
+                  testCodeOwnerBackend.getClass().getName()));
+    }
+  }
+
+  @Test
+  @GerritConfig(name = "plugin.code-owners.backend", value = "find-owners")
+  public void matchAllFilesInSubfolder_findOwnersBackend() throws Exception {
+    assertThat(testPathExpressions.matchAllFilesInSubfolder("foo")).isEqualTo("foo/**");
+  }
+
+  @Test
+  @GerritConfig(name = "plugin.code-owners.backend", value = "proto")
+  public void matchAllFilesInSubfolder_protoBackend() throws Exception {
+    assertThat(testPathExpressions.matchAllFilesInSubfolder("foo")).isEqualTo("foo/...");
+  }
+
+  @Test
+  @GerritConfig(name = "plugin.code-owners.backend", value = TestCodeOwnerBackend.ID)
+  public void matchAllFilesInSubfolder_backendWithGlobMatcher() throws Exception {
+    try (AutoCloseable registration = registerTestBackend(GlobMatcher.INSTANCE)) {
+      assertThat(testPathExpressions.matchAllFilesInSubfolder("foo")).isEqualTo("foo/**");
+    }
+  }
+
+  @Test
+  @GerritConfig(name = "plugin.code-owners.backend", value = TestCodeOwnerBackend.ID)
+  public void matchAllFilesInSubfolder_backendWithUnknownMatcher() throws Exception {
+    PathExpressionMatcher pathExpressionMatcher =
+        new PathExpressionMatcher() {
+          @Override
+          public boolean matches(String pathExpression, Path relativePath) {
+            return false;
+          }
+        };
+    try (AutoCloseable registration = registerTestBackend(pathExpressionMatcher)) {
+      IllegalStateException exception =
+          assertThrows(
+              IllegalStateException.class,
+              () -> testPathExpressions.matchAllFilesInSubfolder("foo"));
+      assertThat(exception)
+          .hasMessageThat()
+          .isEqualTo(
+              String.format(
+                  "path expression matcher %s not supported",
+                  pathExpressionMatcher.getClass().getName()));
+    }
+  }
+
+  @Test
+  @GerritConfig(name = "plugin.code-owners.backend", value = TestCodeOwnerBackend.ID)
+  public void matchAllFilesInSubfolder_backendWithoutMatcher() throws Exception {
+    TestCodeOwnerBackend testCodeOwnerBackend =
+        new TestCodeOwnerBackend(/* pathExpressionMatcher= */ null);
+    try (AutoCloseable registration = registerTestBackend(testCodeOwnerBackend)) {
+      IllegalStateException exception =
+          assertThrows(
+              IllegalStateException.class,
+              () -> testPathExpressions.matchAllFilesInSubfolder("foo"));
+      assertThat(exception)
+          .hasMessageThat()
+          .isEqualTo(
+              String.format(
+                  "code owner backend %s doesn't support path expressions",
+                  testCodeOwnerBackend.getClass().getName()));
+    }
+  }
+
+  private AutoCloseable registerTestBackend(PathExpressionMatcher pathExpressionMatcher) {
+    return registerTestBackend(new TestCodeOwnerBackend(pathExpressionMatcher));
+  }
+
+  private AutoCloseable registerTestBackend(CodeOwnerBackend codeOwnerBackend) {
+    RegistrationHandle registrationHandle =
+        ((PrivateInternals_DynamicMapImpl<CodeOwnerBackend>) codeOwnerBackends)
+            .put("gerrit", TestCodeOwnerBackend.ID, Providers.of(codeOwnerBackend));
+    return registrationHandle::remove;
+  }
+
+  private static class TestCodeOwnerBackend implements CodeOwnerBackend {
+    static final String ID = "test-backend";
+
+    @Nullable private final PathExpressionMatcher pathExpressionMatcher;
+
+    public TestCodeOwnerBackend(@Nullable PathExpressionMatcher pathExpressionMatcher) {
+      this.pathExpressionMatcher = pathExpressionMatcher;
+    }
+
+    @Override
+    public boolean isCodeOwnerConfigFile(NameKey project, String fileName) {
+      throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public Optional<CodeOwnerConfig> getCodeOwnerConfig(
+        CodeOwnerConfig.Key codeOwnerConfigKey, RevWalk revWalk, ObjectId revision) {
+      throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public Path getFilePath(CodeOwnerConfig.Key codeOwnerConfigKey) {
+      throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public Optional<CodeOwnerConfig> upsertCodeOwnerConfig(
+        CodeOwnerConfig.Key codeOwnerConfigKey,
+        CodeOwnerConfigUpdate codeOwnerConfigUpdate,
+        IdentifiedUser currentUser) {
+      throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public Optional<PathExpressionMatcher> getPathExpressionMatcher() {
+      return Optional.ofNullable(pathExpressionMatcher);
+    }
+  }
+}
diff --git a/javatests/com/google/gerrit/plugins/codeowners/backend/CodeOwnerConfigHierarchyTest.java b/javatests/com/google/gerrit/plugins/codeowners/backend/CodeOwnerConfigHierarchyTest.java
index a99de99..4df0138 100644
--- a/javatests/com/google/gerrit/plugins/codeowners/backend/CodeOwnerConfigHierarchyTest.java
+++ b/javatests/com/google/gerrit/plugins/codeowners/backend/CodeOwnerConfigHierarchyTest.java
@@ -540,7 +540,7 @@
             .addCodeOwnerSet(
                 CodeOwnerSet.builder()
                     .setIgnoreGlobalAndParentCodeOwners()
-                    .addPathExpression(testPathExpressions.matchFileTypeInCurrentFolder("txt"))
+                    .addPathExpression(testPathExpressions.matchFileType("txt"))
                     .addCodeOwnerEmail(admin.email())
                     .build())
             .create();