fix: make chat creation idempotent

app/(chat)/api/chat/route.ts

@@ -4456,9 +4456,27 @@ const SMART_AUTO_GRAPH_TIMEOUT_MS = 28_000;
 const SMART_AUTO_FALLBACK_TIMEOUT_MS = 20_000;
 const SMART_AUTO_IMAGE_SUMMARY_TIMEOUT_MS = 18_000;
 const DEFAULT_STREAM_KEEPALIVE_INTERVAL_MS = 12_000;
+const CHAT_CREATION_LOOKUP_RETRY_DELAYS_MS = [60, 180, 360] as const;
 
 const sleep = (ms: number) => new Promise((resolve) => setTimeout(resolve, ms));
 
+async function findChatWithRetry(chatId: string) {
+  let currentChat = await getChatById({ id: chatId });
+  if (currentChat) {
+    return currentChat;
+  }
+
+  for (const delayMs of CHAT_CREATION_LOOKUP_RETRY_DELAYS_MS) {
+    await sleep(delayMs);
+    currentChat = await getChatById({ id: chatId });
+    if (currentChat) {
+      return currentChat;
+    }
+  }
+
+  return null;
+}
+
 class OperationTimeoutError extends Error {
   constructor(operation: string, timeoutMs: number) {
     super(`${operation} timed out after ${timeoutMs}ms`);
@@ -6276,7 +6294,7 @@ export async function POST(request: Request) {
           visibility: selectedVisibilityType,
         });
       } catch (error) {
-        const racedChat = await getChatById({ id });
+        const racedChat = await findChatWithRetry(id);
         if (!racedChat) {
           throw error;
         }
@@ -6291,7 +6309,7 @@ export async function POST(request: Request) {
         });
       }
 
-      chat = await getChatById({ id });
+      chat = await findChatWithRetry(id);
       if (!chat) {
         throw new ChatSDKError("bad_request:database", "Failed to save chat");
       }

lib/db/queries.ts

@@ -168,13 +168,18 @@ export async function saveChat({
   visibility: VisibilityType;
 }) {
   try {
-    return await db.insert(chat).values({
-      id,
-      createdAt: new Date(),
-      userId,
-      title,
-      visibility,
-    });
+    return await db
+      .insert(chat)
+      .values({
+        id,
+        createdAt: new Date(),
+        userId,
+        title,
+        visibility,
+      })
+      .onConflictDoNothing({
+        target: chat.id,
+      });
   } catch (_error) {
     throw new ChatSDKError("bad_request:database", "Failed to save chat");
   }