fix: comment change events

core/comments/workspace_comment.ts

@@ -75,9 +75,20 @@ export class WorkspaceComment {
     }
   }
 
+  /** Fires a comment change event. */
+  private fireChangeEvent(oldText: string, newText: string) {
+    if (eventUtils.isEnabled()) {
+      eventUtils.fire(
+        new (eventUtils.get(eventUtils.COMMENT_CHANGE))(this, oldText, newText),
+      );
+    }
+  }
+
   /** Sets the text of the comment. */
   setText(text: string) {
+    const oldText = this.text;
     this.text = text;
+    this.fireChangeEvent(oldText, text);
   }
 
   /** Returns the text of the comment. */

core/events/events_comment_change.ts

@@ -124,13 +124,16 @@ export class CommentChange extends CommentBase {
           'the constructor, or call fromJson',
       );
     }
-    const comment = workspace.getCommentById(this.commentId);
+    // TODO: Remove the cast when we fix the type of getCommentById.
+    const comment = workspace.getCommentById(
+      this.commentId,
+    ) as unknown as WorkspaceComment;
     if (!comment) {
       console.warn("Can't change non-existent comment: " + this.commentId);
       return;
     }
     const contents = forward ? this.newContents_ : this.oldContents_;
-    if (!contents) {
+    if (contents === undefined) {
       if (forward) {
         throw new Error(
           'The new contents is undefined. Either pass a value to ' +
@@ -142,7 +145,7 @@ export class CommentChange extends CommentBase {
           'the constructor, or call fromJson',
       );
     }
-    comment.setContent(contents);
+    comment.setText(contents);
   }
 }