fix(aio): honor task detail 404 only on cold cache misses

The task detail routes redirected away on any 404 from the detail query,
even when a cached or list copy of the task exists. Optimistic and
cloud-pending tasks are not returnable by the API yet (see the route
loader comments), so the unconditional redirect kicked users off tasks
they had just created.

The detail query still always runs (so a stale cached copy converges on
the server's latest run state), but a 404/missing result only triggers
the redirect when there is no usable cached task to render.

Generated-By: PostHog Code
Task-Id: 0c511836-2180-455a-9b58-45df2a0661ec

Author: tatoalo

packages/ui/src/router/routes/code/tasks/$taskId.tsx

@@ -3,7 +3,6 @@ import { TaskDetail } from "@posthog/ui/features/task-detail/components/TaskDeta
 import {
   getCachedTask,
   getCachedTaskDetail,
-  isTaskDetailNotFoundError,
   taskDetailQuery,
 } from "@posthog/ui/features/tasks/queries";
 import { pickFreshestTask } from "@posthog/ui/features/tasks/taskFreshness";
@@ -41,25 +40,24 @@ function TaskDetailRoute() {
   const fromList = tasks?.find((t) => t.id === taskId);
   const initialTask = pickFreshestTask(fromList, loaderTask);
 
-  // Cold deep-link / URL restore: nothing cached. Fetch the single task here so
-  // a hang or 404 only affects this view's spinner, never the router.
-  const needsFetch = !initialTask;
+  // Always fetch so a stale cached copy converges on the server's latest run
+  // state; render whichever copy is freshest.
   const {
     data: fetched,
-    error,
     isError,
     isSuccess,
   } = useQuery(taskDetailQuery(taskId));
 
   const task = pickFreshestTask(fetched, initialTask);
 
-  // Task doesn't exist (deleted, 404, or stale deep link): the cold fetch
-  // settled with an error or empty result. Redirect to the new-task screen
-  // rather than spin forever — matches the old navigationStore.hydrateTask.
-  if (
-    isTaskDetailNotFoundError(error) ||
-    (needsFetch && (isError || (isSuccess && !fetched)))
-  ) {
+  // Cold deep-link / URL restore with nothing cached: if the fetch settled
+  // with an error or empty result, redirect to the new-task screen rather
+  // than spin forever — matches the old navigationStore.hydrateTask. While a
+  // cached/list copy exists, a 404 is NOT authoritative (optimistic and
+  // cloud-pending tasks aren't returnable by the API yet — see the loader
+  // comment), so never redirect away from a usable task.
+  const needsFetch = !initialTask;
+  if (needsFetch && (isError || (isSuccess && !fetched))) {
     return <Navigate replace to="/code" />;
   }
 

packages/ui/src/router/routes/website/$channelId/tasks/$taskId.tsx

@@ -73,7 +73,10 @@ function ChannelTaskDetailRoute() {
 
   const task = pickFreshestTask(fetched, initialTask);
 
-  if (isTaskDetailNotFoundError(error)) {
+  // While a cached/list copy exists, a 404 is NOT authoritative (optimistic
+  // and cloud-pending tasks aren't returnable by the API yet — see the loader
+  // comment), so only treat the task as gone when nothing cached is usable.
+  if (!initialTask && isTaskDetailNotFoundError(error)) {
     return <Navigate replace to="/website/$channelId" params={{ channelId }} />;
   }