fix(app-shell): the chatter reads and writes reactions as the member's own sys_comment_reaction records (objectui#12078)

.changeset/12078-reaction-records.md

@@ -0,0 +1,14 @@
+---
+'@object-ui/app-shell': patch
+---
+
+The record chatter stores each reaction as the member's own `sys_comment_reaction` record, and stops writing the whole `sys_comment.reactions` column (objectui#12078; ruling A, amended, on objectstack-ai/objectstack#22505).
+
+A reaction click used to write the comment's whole reaction set back with one `sys_comment` update. Two members reacting at the same moment therefore left only the later write stored. A member who could read a record but not edit it could not react to another member's comment either, because that update is the comment author's (or a parent editor's) to make.
+
+- **Read.** After the comment read, the chatter reads the comments' reactions in one `sys_comment_reaction` read, `comment_id` `$in` the comment ids, and groups the rows into the reactions the panel already renders. It never reads per comment. A thread of more than 100 comments is read in pages of 100 ids, in parallel, which keeps each request URL near 4.6 KB.
+- **Write.** A click creates the member's own reaction row (`comment_id`, `emoji`; the server stamps `user_id`), and a second click deletes that row. Nothing else is written, so another member's reaction can no longer be overwritten, and both of two simultaneous reactions stay. A refused write puts the reaction back and shows the same "Your reaction was not saved" error as before.
+- **Reactions stored only in the column are not shown** where the object exists. The maintainer ruled that the column's reactions need no migration.
+- **A deployment without `sys_comment_reaction` keeps the column path, unchanged.** This covers a framework that predates objectstack-ai/objectstack#22566, such as cloud's v17 pin. The chatter asks the object registry it already loads. Only an earned "absent" answer keeps the column path; a registry that lists nothing, or has not answered, is not read as absence. The comment read waits until the registry has answered.
+
+Nothing on the package entry changes: no export, prop, type member or language-pack key. `CommentThread` (`@object-ui/collaboration`) and `Reaction` (`@object-ui/types`) are untouched.

packages/app-shell/src/views/RecordDetailView.reactionKeepIds-11019.test.tsx

@@ -17,6 +17,11 @@
  * data source whose `sys_comment` `update` payload is the observed channel. The
  * signed-in user is the varied axis, so one case can hand the row a first user
  * stored and read it back as a second user.
+ *
+ * Since objectui#12078 this is the column store, which the page uses only where
+ * the deployment has no `sys_comment_reaction` (the registry below lists none).
+ * Where it has one, a click writes the member's own reaction row instead:
+ * `RecordDetailView.reactionRecords-12078.test.tsx`.
  */
 
 import * as React from 'react';
@@ -124,7 +129,10 @@ async function mountAs(userId: string, dataSource: any) {
     invalidate: () => {},
     ensureType: async () => pages,
     getItem: async () => null,
-    getItemsByType: (type: string) => (type === 'page' ? pages : []),
+    // The registry lists this deployment's objects, and `sys_comment_reaction`
+    // is not one of them, so the page keeps reactions in the
+    // `sys_comment.reactions` column (objectui#12078).
+    getItemsByType: (type: string) => (type === 'page' ? pages : type === 'object' ? OBJECTS : []),
   } as any;
   render(
     <MemoryRouter initialEntries={[`/app/demo/${OBJECT_NAME}/${RECORD_ID}`]}>