From ab0b4ab5921d0ce5cf6566637765cbcd1aa450b8 Mon Sep 17 00:00:00 2001
From: Tao Zhou <taoalpha@google.com>
Date: Mon, 18 May 2020 13:28:20 +0200
Subject: [PATCH] Fix `parent` in `gr-change-metadata` when switching patchsets

Bug: Issue 12775
Change-Id: I33c88df5e01b9659256b11f70df7f9442cb5cb9e
(cherry picked from commit a37843174cbd1aca972b9dda871953bd76dd6588)
---
 .../gr-change-metadata/gr-change-metadata.js  | 10 ++++-----
 .../gr-change-metadata_test.html              | 22 ++++++++++++-------
 2 files changed, 18 insertions(+), 14 deletions(-)

diff --git a/polygerrit-ui/app/elements/change/gr-change-metadata/gr-change-metadata.js b/polygerrit-ui/app/elements/change/gr-change-metadata/gr-change-metadata.js
index a540665e30..518634735f 100644
--- a/polygerrit-ui/app/elements/change/gr-change-metadata/gr-change-metadata.js
+++ b/polygerrit-ui/app/elements/change/gr-change-metadata/gr-change-metadata.js
@@ -131,7 +131,7 @@
 
       _currentParents: {
         type: Array,
-        computed: '_computeParents(change)',
+        computed: '_computeParents(revision)',
       },
 
       /** @type {?} */
@@ -445,13 +445,11 @@
       return null;
     },
 
-    _computeParents(change) {
-      if (!change.current_revision ||
-          !change.revisions[change.current_revision] ||
-          !change.revisions[change.current_revision].commit) {
+    _computeParents(revision) {
+      if (!revision || !revision.commit) {
         return undefined;
       }
-      return change.revisions[change.current_revision].commit.parents;
+      return revision.commit.parents;
     },
 
     _computeParentsLabel(parents) {
diff --git a/polygerrit-ui/app/elements/change/gr-change-metadata/gr-change-metadata_test.html b/polygerrit-ui/app/elements/change/gr-change-metadata/gr-change-metadata_test.html
index fcbd3d5fb9..946524617f 100644
--- a/polygerrit-ui/app/elements/change/gr-change-metadata/gr-change-metadata_test.html
+++ b/polygerrit-ui/app/elements/change/gr-change-metadata/gr-change-metadata_test.html
@@ -429,14 +429,20 @@ limitations under the License.
     });
 
     test('_computeParents', () => {
-      const parents = [{commit: '123', subject: 'abc'}];
-      assert.isUndefined(element._computeParents(
-          {revisions: {456: {commit: {parents}}}}));
-      assert.isUndefined(element._computeParents(
-          {current_revision: '789', revisions: {456: {commit: {parents}}}}));
-      assert.equal(element._computeParents(
-          {current_revision: '456', revisions: {456: {commit: {parents}}}}),
-      parents);
+      const revision = {commit: {parents: [{commit: '123', subject: 'abc'}]}};
+      assert.isUndefined(element._computeParents({}));
+      assert.equal(element._computeParents(revision), revision.commit.parents);
+    });
+
+    test('_currentParents', () => {
+      element.revision = {
+        commit: {parents: [{commit: '123', subject: 'abc'}]},
+      };
+      assert.equal(element._currentParents[0].commit, '123');
+      element.revision = {
+        commit: {parents: [{commit: '12345', subject: 'abc'}]},
+      };
+      assert.equal(element._currentParents[0].commit, '12345');
     });
 
     test('_computeParentsLabel', () => {