fix(chat): a failure after the message insert no longer writes a second copy (TASK-313)

backend/__tests__/unit/models/PgMessageCreateAfterInsert.test.js

@@ -0,0 +1,70 @@
+// TASK-313: once the INSERT has committed, a failure in the pod touch or the
+// attention bookkeeping must not reject create(). The controller's Mongo
+// fallback would otherwise write a second copy of a message that is already
+// in Postgres.
+jest.mock('../../../config/db-pg', () => ({
+  pool: {
+    query: jest.fn(),
+  },
+}));
+
+const mockRecordMentionedUsers = jest.fn();
+const mockResolveMentionAttentionForReply = jest.fn();
+jest.mock('../../../services/attentionItemService', () => ({
+  recordMentionedUsers: (...args) => mockRecordMentionedUsers(...args),
+  resolveMentionAttentionForReply: (...args) => mockResolveMentionAttentionForReply(...args),
+  resolve: jest.fn(),
+  resolveMany: jest.fn(),
+}));
+
+const { pool } = require('../../../config/db-pg');
+const Message = require('../../../models/pg/Message');
+
+const insertedRow = {
+  id: '7',
+  pod_id: 'p',
+  user_id: 'u',
+  content: 'hello',
+  message_type: 'text',
+  created_at: new Date('2026-10-23T00:00:00Z'),
+  thread_root_id: null,
+  reply_to_message_id: null,
+};
+
+describe('PG Message create after the insert has committed', () => {
+  beforeEach(() => {
+    jest.clearAllMocks();
+    mockRecordMentionedUsers.mockResolvedValue(undefined);
+    mockResolveMentionAttentionForReply.mockResolvedValue(0);
+  });
+
+  it('resolves with the inserted row when the pod touch fails', async () => {
+    pool.query
+      .mockResolvedValueOnce({ rows: [insertedRow] })
+      .mockRejectedValueOnce(new Error('pod update failed'));
+
+    const row = await Message.create('p', 'u', 'hello', 'text', null, null, null);
+
+    expect(row.id).toBe('7');
+    expect(mockRecordMentionedUsers).toHaveBeenCalledTimes(1);
+  });
+
+  it('resolves with the inserted row when attention bookkeeping fails', async () => {
+    pool.query
+      .mockResolvedValueOnce({ rows: [insertedRow] })
+      .mockResolvedValueOnce({ rows: [] });
+    mockRecordMentionedUsers.mockRejectedValueOnce(new Error('attention write failed'));
+
+    const row = await Message.create('p', 'u', 'hello', 'text', null, null, null);
+
+    expect(row.id).toBe('7');
+  });
+
+  it('still throws before the insert when the reply target is not in the pod', async () => {
+    pool.query.mockResolvedValueOnce({ rows: [] });
+
+    await expect(Message.create('p', 'u', 'hello', 'text', '99', null, null))
+      .rejects.toThrow(/not in this pod|reply_target_unavailable|ThreadRoot/i);
+    expect(pool.query).toHaveBeenCalledTimes(1);
+  });
+});

backend/models/pg/Message.ts

@@ -176,26 +176,38 @@ class Message {
         const { ThreadRootError } = require('../../services/threadRootResolver');
         throw new ThreadRootError('reply_target_unavailable', 'the message being replied to is not in this pod');
       }
-      await (pool as PgPool).query(
-        'UPDATE pods SET updated_at = CURRENT_TIMESTAMP WHERE id = $1',
-        [podId],
-      );
       const row = result.rows[0] as unknown as MessageRow;
-      // eslint-disable-next-line global-require
-      const {
-        recordMentionedUsers,
-        resolveMentionAttentionForReply,
-      } = require('../../services/attentionItemService');
-      await recordMentionedUsers({
-        ...row, podId, userId, content, threadRootId: resolvedThreadRootId, answeringMessageId,
-      });
-      await resolveMentionAttentionForReply({
-        podId,
-        recipientUserId: userId,
-        repliedAt: row.created_at,
-        threadRootId: row.thread_root_id,
-        replyToMessageId: row.reply_to_message_id,
-      });
+      // The INSERT has committed. Nothing below may reject back to the caller:
+      // the controller's Mongo fallback would then write a second copy of a
+      // message that is already in Postgres (TASK-313). Each step is best
+      // effort and logged, the same way the post-write read is.
+      try {
+        await (pool as PgPool).query(
+          'UPDATE pods SET updated_at = CURRENT_TIMESTAMP WHERE id = $1',
+          [podId],
+        );
+      } catch (touchErr) {
+        console.warn('[Message.create] pod touch failed after insert:', (touchErr as Error).message);
+      }
+      try {
+        // eslint-disable-next-line global-require
+        const {
+          recordMentionedUsers,
+          resolveMentionAttentionForReply,
+        } = require('../../services/attentionItemService');
+        await recordMentionedUsers({
+          ...row, podId, userId, content, threadRootId: resolvedThreadRootId, answeringMessageId,
+        });
+        await resolveMentionAttentionForReply({
+          podId,
+          recipientUserId: userId,
+          repliedAt: row.created_at,
+          threadRootId: row.thread_root_id,
+          replyToMessageId: row.reply_to_message_id,
+        });
+      } catch (attentionErr) {
+        console.warn('[Message.create] attention bookkeeping failed after insert:', (attentionErr as Error).message);
+      }
       return row;
     } catch (error) {
       const e = error as { message?: string };