ListTags: Include timestamp in tag info

The tags are listed in alphanumeric order, but some clients may wish
to order the tags by the date they were created.

Add a timestamp in the tag info.

For annotated/signed tags, the timestamp is the date at which the tag
was created.

For lightweight tags, the timestamp is set to the committer timestamp,
only when the tag is on a commit.

Change-Id: I34f49f19810fa430769a50b5ae43b8107527792b

Documentation/rest-api-projects.txt

@@ -3331,6 +3331,11 @@ tag points.
 the signature.
 |`tagger`|Only set for annotated tags, if present in the tag.|The tagger as a
 link:rest-api-changes.html#git-person-info[GitPersonInfo] entity.
+|`created`|optional|The link:rest-api.html#timestamp[timestamp] of when the tag
+was created. For annotated and signed tags, this is the timestamp of the tag object
+and is the same as the `date` field in the `tagger`. For lightweight tags, it is
+the commit timestamp of the commit to which the tag points, when the object is a
+commit. It is not set when the object is any other type.
 |`can_delete`|not set if `false`|
 Whether the calling user can delete this tag.
 |`web_links` |optional|

java/com/google/gerrit/extensions/api/projects/TagInfo.java

@@ -16,19 +16,47 @@ package com.google.gerrit.extensions.api.projects;
 
 import com.google.gerrit.extensions.common.GitPerson;
 import com.google.gerrit.extensions.common.WebLinkInfo;
+import java.sql.Timestamp;
 import java.util.List;
 
 public class TagInfo extends RefInfo {
   public String object;
   public String message;
   public GitPerson tagger;
+  public Timestamp created;
   public List<WebLinkInfo> webLinks;
 
-  public TagInfo(String ref, String revision, Boolean canDelete, List<WebLinkInfo> webLinks) {
+  public TagInfo(
+      String ref,
+      String revision,
+      Boolean canDelete,
+      List<WebLinkInfo> webLinks,
+      Timestamp created) {
     this.ref = ref;
     this.revision = revision;
     this.canDelete = canDelete;
     this.webLinks = webLinks;
+    this.created = created;
+  }
+
+  public TagInfo(String ref, String revision, Boolean canDelete, List<WebLinkInfo> webLinks) {
+    this(ref, revision, canDelete, webLinks, null);
+  }
+
+  public TagInfo(
+      String ref,
+      String revision,
+      String object,
+      String message,
+      GitPerson tagger,
+      Boolean canDelete,
+      List<WebLinkInfo> webLinks,
+      Timestamp created) {
+    this(ref, revision, canDelete, webLinks, created);
+    this.object = object;
+    this.message = message;
+    this.tagger = tagger;
+    this.webLinks = webLinks;
   }
 
   public TagInfo(
@@ -39,7 +67,7 @@ public class TagInfo extends RefInfo {
       GitPerson tagger,
       Boolean canDelete,
       List<WebLinkInfo> webLinks) {
-    this(ref, revision, canDelete, webLinks);
+    this(ref, revision, object, message, tagger, canDelete, webLinks, null);
     this.object = object;
     this.message = message;
     this.tagger = tagger;

java/com/google/gerrit/server/project/ListTags.java

@@ -33,6 +33,7 @@ import com.google.gerrit.server.permissions.RefPermission;
 import com.google.inject.Inject;
 import com.google.inject.Provider;
 import java.io.IOException;
+import java.sql.Timestamp;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.Comparator;
@@ -44,6 +45,7 @@ import org.eclipse.jgit.lib.Constants;
 import org.eclipse.jgit.lib.PersonIdent;
 import org.eclipse.jgit.lib.Ref;
 import org.eclipse.jgit.lib.Repository;
+import org.eclipse.jgit.revwalk.RevCommit;
 import org.eclipse.jgit.revwalk.RevObject;
 import org.eclipse.jgit.revwalk.RevTag;
 import org.eclipse.jgit.revwalk.RevWalk;
@@ -201,16 +203,24 @@ public class ListTags implements RestReadView<ProjectResource> {
           tag.getName(),
           tag.getObject().getName(),
           tag.getFullMessage().trim(),
-          tagger != null ? CommonConverters.toGitPerson(tag.getTaggerIdent()) : null,
+          tagger != null ? CommonConverters.toGitPerson(tagger) : null,
           canDelete,
-          webLinks.isEmpty() ? null : webLinks);
+          webLinks.isEmpty() ? null : webLinks,
+          tagger != null ? new Timestamp(tagger.getWhen().getTime()) : null);
     }
+
+    Timestamp timestamp =
+        object instanceof RevCommit
+            ? new Timestamp(((RevCommit) object).getCommitterIdent().getWhen().getTime())
+            : null;
+
     // Lightweight tag
     return new TagInfo(
         ref.getName(),
         ref.getObjectId().getName(),
         canDelete,
-        webLinks.isEmpty() ? null : webLinks);
+        webLinks.isEmpty() ? null : webLinks,
+        timestamp);
   }
 
   private Repository getRepository(Project.NameKey project)

javatests/com/google/gerrit/acceptance/rest/project/TagsIT.java

@@ -33,6 +33,7 @@ import com.google.gerrit.extensions.restapi.BadRequestException;
 import com.google.gerrit.extensions.restapi.MethodNotAllowedException;
 import com.google.gerrit.extensions.restapi.ResourceConflictException;
 import com.google.gerrit.extensions.restapi.ResourceNotFoundException;
+import java.sql.Timestamp;
 import java.util.List;
 import org.junit.Test;
 
@@ -177,12 +178,14 @@ public class TagsIT extends AbstractDaemonTest {
     assertThat(result.ref).isEqualTo(R_TAGS + input.ref);
     assertThat(result.revision).isEqualTo(input.revision);
     assertThat(result.canDelete).isTrue();
+    assertThat(result.created).isEqualTo(timestamp(r));
 
     input.ref = "refs/tags/v2.0";
     result = tag(input.ref).create(input).get();
     assertThat(result.ref).isEqualTo(input.ref);
     assertThat(result.revision).isEqualTo(input.revision);
     assertThat(result.canDelete).isTrue();
+    assertThat(result.created).isEqualTo(timestamp(r));
 
     setApiUser(user);
     result = tag(input.ref).get();
@@ -210,6 +213,7 @@ public class TagsIT extends AbstractDaemonTest {
     assertThat(result.message).isEqualTo(input.message);
     assertThat(result.tagger.name).isEqualTo(admin.fullName);
     assertThat(result.tagger.email).isEqualTo(admin.email);
+    assertThat(result.created).isEqualTo(result.tagger.date);
 
     eventRecorder.assertRefUpdatedEvents(project.get(), result.ref, null, result.revision);
 
@@ -224,6 +228,7 @@ public class TagsIT extends AbstractDaemonTest {
     assertThat(result2.message).isEqualTo(input2.message);
     assertThat(result2.tagger.name).isEqualTo(admin.fullName);
     assertThat(result2.tagger.email).isEqualTo(admin.email);
+    assertThat(result2.created).isEqualTo(result2.tagger.date);
 
     eventRecorder.assertRefUpdatedEvents(project.get(), result2.ref, null, result2.revision);
   }
@@ -325,7 +330,9 @@ public class TagsIT extends AbstractDaemonTest {
       throws Exception {
     assertThat(actual).hasSize(expected.size());
     for (int i = 0; i < expected.size(); i++) {
-      assertThat(actual.get(i).ref).isEqualTo(R_TAGS + expected.get(i));
+      TagInfo info = actual.get(i);
+      assertThat(info.created).isNotNull();
+      assertThat(info.ref).isEqualTo(R_TAGS + expected.get(i));
     }
   }
 
@@ -351,6 +358,10 @@ public class TagsIT extends AbstractDaemonTest {
     return gApi.projects().name(project.get()).tag(tagname);
   }
 
+  private Timestamp timestamp(PushOneCommit.Result r) {
+    return new Timestamp(r.getCommit().getCommitterIdent().getWhen().getTime());
+  }
+
   private void assertBadRequest(ListRefsRequest<TagInfo> req) throws Exception {
     try {
       req.get();