Fix deleting edits when change is merged

This fixes supporting deleting a change edit after change is
merged or abandoned.

This also improves the user interaction so a dialog is not
shown because a change edit didn't exist on /commit?links.

Rather we now write to the console log.

This also has the benefit of making the redirect of /edit -> ,edit
seamless because no more dialog showing and having to press close
which could cause some confusion with the user.

Since we're redirecting /edit -> ,edit anyways we don't need the dialog.

Change-Id: I2e478d203ae7eb95acf92b518b73c9ad6b73c77d

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

diff --git a/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.ts b/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.ts
index 39a80e6..0c55f67 100644
--- a/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.ts
+++ b/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.ts
@@ -76,8 +76,9 @@
   PatchSet,
 } from '../../../utils/patch-set-util';
 import {
-  changeIsMerged,
   changeIsAbandoned,
+  changeIsMerged,
+  changeIsOpen,
   changeStatuses,
   isCc,
   isOwner,
@@ -1768,6 +1769,17 @@
    */
   _processEdit(change: ParsedChangeInfo, edit?: EditInfo | false) {
     if (
+      !edit &&
+      this._patchRange?.patchNum === EditPatchSetNum &&
+      changeIsOpen(change)
+    ) {
+      fireAlert(this, 'Change edit not found. Please create a change edit.');
+      GerritNav.navigateToChange(change);
+      return;
+    }
+
+    if (
+      !edit &&
       (changeIsMerged(change) || changeIsAbandoned(change)) &&
       this._editMode
     ) {
@@ -1970,13 +1982,32 @@
 
   _getCommitInfo() {
     if (!this._changeNum)
-      throw new Error('missing required changeNum property');
+      throw new Error('missing required _changeNum property');
     if (!this._patchRange)
       throw new Error('missing required _patchRange property');
     if (this._patchRange.patchNum === undefined)
       throw new Error('missing required patchNum property');
+
+    // We only call _getEdit if the patchset number is an edit.
+    // We have to do this to ensure we can tell if an edit
+    // exists or not.
+    // This safely works even if a edit does not exist.
+    if (this._patchRange!.patchNum! === EditPatchSetNum) {
+      return this._getEdit().then(edit => {
+        if (!edit) {
+          return Promise.resolve();
+        }
+
+        return this._getChangeCommitInfo();
+      });
+    }
+
+    return this._getChangeCommitInfo();
+  }
+
+  _getChangeCommitInfo() {
     return this.restApiService
-      .getChangeCommitInfo(this._changeNum, this._patchRange.patchNum)
+      .getChangeCommitInfo(this._changeNum!, this._patchRange!.patchNum!)
       .then(commitInfo => {
         this._commitInfo = commitInfo;
       });