fix(chat): don't flash the legacy notice for in-flight messages

Author: kfaracik

__tests__/legacyChat.test.ts

@@ -102,6 +102,35 @@ describe('chatPredatesSourceLinking', () => {
     expect(chatPredatesSourceLinking([], BOUNDARY)).toBe(false);
   });
 
+  it('ignores an optimistic message still carrying its negative placeholder id', () => {
+    expect(
+      chatPredatesSourceLinking(
+        [
+          message({
+            id: -1785487200000,
+            role: 'user',
+            documentName: 'new.pdf',
+          }),
+          message({ id: -1, role: 'assistant', content: '' }),
+        ],
+        BOUNDARY
+      )
+    ).toBe(false);
+  });
+
+  it('still flags a genuine legacy chat that also has an in-flight message', () => {
+    expect(
+      chatPredatesSourceLinking(
+        [
+          message({ id: 10, role: 'user', documentName: 'report.pdf' }),
+          message({ id: 11, role: 'assistant', content: 'summary' }),
+          message({ id: -1785487200000, role: 'user', content: 'follow-up' }),
+        ],
+        BOUNDARY
+      )
+    ).toBe(true);
+  });
+
   it('reads the module boundary when none is passed', () => {
     setSourceLinkingBoundary(BOUNDARY);
     expect(

utils/legacyChat.ts

@@ -7,6 +7,8 @@ export type LegacyChatDiagnosis = {
   isLegacy: boolean;
 };
 
+const isPersisted = (message: Message) => message.id > 0;
+
 // Both checks are scoped to the pre-boundary era (id <= boundary) on purpose: a
 // new turn that retrieves a source (id > boundary) must not flip a legacy chat to
 // "linked" and drop the notice mid-conversation.
@@ -15,10 +17,14 @@ export const diagnoseLegacyChat = (
   boundaryMessageId: number = getSourceLinkingBoundary()
 ): LegacyChatDiagnosis => {
   const hasLegacyDocument = messages.some(
-    (message) => !!message.documentName && message.id <= boundaryMessageId
+    (message) =>
+      !!message.documentName &&
+      isPersisted(message) &&
+      message.id <= boundaryMessageId
   );
   const hasSourceLinking = messages.some(
     (message) =>
+      isPersisted(message) &&
       message.id <= boundaryMessageId &&
       !!message.sourceDocuments &&
       message.sourceDocuments.length > 0