Reload ported comments when patchset picker is changed

Ranges calculated for ported comments depend on the patchNum, hence
request ported comments if user updates the patchset choice using
the patchset picker.

Change-Id: Ib3e4efa244f2cb15d2e223bf5cba5caade236010

polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.ts

@@ -1252,6 +1252,11 @@ export class GrChangeView extends KeyboardShortcutMixin(
         this._patchRange.basePatchNum !== value.basePatchNum);
     const changeChanged = this._changeNum !== value.changeNum;
 
+    let rightPatchNumChanged =
+      this._patchRange &&
+      value.patchNum !== undefined &&
+      this._patchRange.patchNum !== value.patchNum;
+
     const patchRange: ChangeViewPatchRange = {
       patchNum: value.patchNum,
       basePatchNum: value.basePatchNum || ParentPatchSetNum,
@@ -1265,8 +1270,9 @@ export class GrChangeView extends KeyboardShortcutMixin(
     if (!changeChanged && patchChanged) {
       if (!patchRange.patchNum) {
         patchRange.patchNum = computeLatestPatchNum(this._allPatchSets);
+        rightPatchNumChanged = true;
       }
-      this._reloadPatchNumDependentResources().then(() => {
+      this._reloadPatchNumDependentResources(rightPatchNumChanged).then(() => {
         this._sendShowChangeEvent();
       });
       return;
@@ -2260,8 +2266,18 @@ export class GrChangeView extends KeyboardShortcutMixin(
    * Kicks off requests for resources that rely on the patch range
    * (`this._patchRange`) being defined.
    */
-  _reloadPatchNumDependentResources() {
-    return Promise.all([this._getCommitInfo(), this.$.fileList.reload()]);
+  _reloadPatchNumDependentResources(rightPatchNumChanged?: boolean) {
+    if (!this._changeNum) throw new Error('missing changeNum');
+    if (!this._patchRange?.patchNum) throw new Error('missing patchNum');
+    const promises = [this._getCommitInfo(), this.$.fileList.reload()];
+    if (rightPatchNumChanged)
+      promises.push(
+        this.$.commentAPI.reloadPortedComments(
+          this._changeNum,
+          this._patchRange?.patchNum
+        )
+      );
+    return Promise.all(promises);
   }
 
   _getMergeability() {

polygerrit-ui/app/elements/change/gr-change-view/gr-change-view_test.ts

@@ -1511,7 +1511,7 @@ suite('gr-change-view tests', () => {
       .callsFake(() => Promise.resolve([]));
     const reloadPatchDependentStub = sinon
       .stub(element, '_reloadPatchNumDependentResources')
-      .callsFake(() => Promise.resolve([undefined, undefined]));
+      .callsFake(() => Promise.resolve([undefined, undefined, undefined]));
     const relatedClearSpy = sinon.spy(element.$.relatedChanges, 'clear');
     const collapseStub = sinon.stub(element.$.fileList, 'collapseAllDiffs');
 
@@ -1535,6 +1535,32 @@ suite('gr-change-view tests', () => {
     assert.isTrue(collapseStub.calledTwice);
   });
 
+  test('reload ported comments when patchNum changes', () => {
+    sinon.stub(element, '_reload').callsFake(() => Promise.resolve([]));
+    sinon.stub(element, '_getCommitInfo');
+    sinon.stub(element.$.fileList, 'reload');
+    const reloadPortedCommentsStub = sinon.stub(
+      element.$.commentAPI,
+      'reloadPortedComments'
+    );
+    sinon.spy(element.$.relatedChanges, 'clear');
+    sinon.stub(element.$.fileList, 'collapseAllDiffs');
+
+    const value: AppElementChangeViewParams = {
+      ...createAppElementChangeViewParams(),
+      view: GerritView.CHANGE,
+      patchNum: 1 as PatchSetNum,
+    };
+    element._paramsChanged(value);
+
+    element._initialLoadComplete = true;
+
+    value.basePatchNum = 1 as PatchSetNum;
+    value.patchNum = 2 as PatchSetNum;
+    element._paramsChanged(value);
+    assert.isTrue(reloadPortedCommentsStub.calledOnce);
+  });
+
   test('reload entire page when patchRange doesnt change', () => {
     const reloadStub = sinon
       .stub(element, '_reload')
@@ -2898,7 +2924,7 @@ suite('gr-change-view tests', () => {
       sinon.stub(element, '_getLatestCommitMessage').returns(Promise.resolve());
       sinon
         .stub(element, '_reloadPatchNumDependentResources')
-        .returns(Promise.resolve([undefined, undefined]));
+        .returns(Promise.resolve([undefined, undefined, undefined]));
     });
 
     test("don't report changeDisplayed on reply", done => {

polygerrit-ui/app/elements/diff/gr-comment-api/gr-comment-api.ts

@@ -274,6 +274,19 @@ export class ChangeComments {
     );
   }
 
+  cloneWithUpdatedPortedComments(
+    portedComments?: PathToCommentsInfoMap,
+    portedDrafts?: PathToCommentsInfoMap
+  ) {
+    return new ChangeComments(
+      this._comments,
+      this._robotComments,
+      this._drafts,
+      portedComments,
+      portedDrafts
+    );
+  }
+
   /**
    * Get the drafts for a path and optional patch num.
    *
@@ -654,6 +667,23 @@ export class GrCommentApi extends GestureEventListeners(
       return this._changeComments;
     });
   }
+
+  reloadPortedComments(changeNum: NumericChangeId, patchNum: PatchSetNum) {
+    if (!this._changeComments) {
+      this.loadAll(changeNum);
+      return Promise.resolve();
+    }
+    return Promise.all([
+      this.restApiService.getPortedComments(changeNum, patchNum),
+      this.restApiService.getPortedDrafts(changeNum, patchNum),
+    ]).then(res => {
+      if (!this._changeComments) return;
+      this._changeComments = this._changeComments.cloneWithUpdatedPortedComments(
+        res[0],
+        res[1]
+      );
+    });
+  }
 }
 
 declare global {