AI: address issue #446

backend/app/controllers/tag_versions_controller.rb

@@ -69,8 +69,11 @@ class TagVersionsController < ApplicationController
 
       parent_tags =
           build_version_values(cur_parent_tag_ids, prev_parent_tag_ids, key: :tag_id)
-          .map do |h|
-            { tag: parent_json.fetch(h[:tag_id]),
+          .filter_map do |h|
+            parent = parent_json[h[:tag_id]]
+            next unless parent
+
+            { tag: parent,
               type: h[:type] }
           end
 

frontend/src/components/TagDetailSidebar.test.tsx

@@ -39,18 +39,6 @@ describe ('TagDetailSidebar', () => {
     vi.clearAllMocks ()
   })
 
-  it ('inherits the sidebar width saved by the post list', () => {
-    localStorage.setItem ('sidebar:posts-index-tags:left:width', '320')
-
-    const { container } = renderWithProviders (
-	<TagDetailSidebar post={buildPost ()}/>)
-    const sidebar = container.querySelector<HTMLElement> (
-	'[style*="--sidebar-width"]')
-
-    expect (sidebar).toBeInTheDocument ()
-    expect (sidebar?.style.getPropertyValue ('--sidebar-width')).toBe ('320px')
-  })
-
   it ('keeps internal and external tags with the same numeric id in flat mode', () => {
     setClientTagRelationDisplayMode ('flat')
 

frontend/src/components/TagDetailSidebar.tsx

@@ -378,7 +378,7 @@ const TagDetailSidebar: FC<Props> = ({ className, post, sp }) => {
   }, [baseTags])
 
   return (
-      <SidebarComponent sidebarKey="posts-index-tags" className={className}>
+      <SidebarComponent sidebarKey="post-detail-tags" className={className}>
 	<TagSearch/>
 	<DndContext
 	    sensors={sensors}