From d9573df8ca4c2c53b8fd25c9d104aedabe0541d6 Mon Sep 17 00:00:00 2001
From: Aaron Dodson <adodson@google.com>
Date: Thu, 20 Feb 2025 13:20:15 -0800
Subject: [PATCH] fix: use derived IDs for block comments

---
 src/engine/adapter.js    |  2 +-
 src/serialization/sb3.js | 10 +++++++++-
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/src/engine/adapter.js b/src/engine/adapter.js
index d10c6874ac9..ce840fde149 100644
--- a/src/engine/adapter.js
+++ b/src/engine/adapter.js
@@ -88,7 +88,7 @@ const domToBlock = function (blockDOM, blocks, isTopBlock, parent) {
         }
         case 'comment':
         {
-            block.comment = xmlChild.attribs.id;
+            block.comment = `${block.id}_comment`;
             break;
         }
         case 'value':
diff --git a/src/serialization/sb3.js b/src/serialization/sb3.js
index c7db58d0b37..18636d17535 100644
--- a/src/serialization/sb3.js
+++ b/src/serialization/sb3.js
@@ -842,6 +842,14 @@ const deserializeBlocks = function (blocks) {
         block.id = blockId; // add id back to block since it wasn't serialized
         block.inputs = deserializeInputs(block.inputs, blockId, blocks);
         block.fields = deserializeFields(block.fields);
+
+        if (block.comment) {
+            // Pre-Blockly v12 Scratch used arbitrary IDs for block comments.
+            // Newer versions use an ID based on the parent block's ID instead,
+            // so disregard the actual saved value and replace it with the
+            // synthesized one.
+            block.comment = `${block.id}_comment`;
+        }
     }
     return blocks;
 };
@@ -1047,7 +1055,7 @@ const parseScratchObject = function (object, runtime, extensions, zip, assets) {
         for (const commentId in object.comments) {
             const comment = object.comments[commentId];
             const newComment = new Comment(
-                commentId,
+                comment.blockId ? `${comment.blockId}_comment` : commentId,
                 comment.text,
                 comment.x,
                 comment.y,