From 5411747726f400dc4c028b9a6487a22d24035b7f Mon Sep 17 00:00:00 2001
From: Daniel Han <danielhanchen@gmail.com>
Date: Sun, 26 Jul 2026 08:00:41 +0000
Subject: [PATCH] Show the retained failure when a video page mounts after a
 failed job

Mount-time recovery handled only phase=completed, so reloading the page
after a multi-minute generation failed left an idle view with no
diagnosis: the backend keeps the terminal failed record only until the
next job, and nothing else survives the reload. Surface it the same way
the poll does, filtering the cancelled sentinel.
---
 studio/backend/tests/test_video_backend.py    | 39 +++++++++++++++++++
 .../src/features/video/video-page.tsx         |  6 +++
 2 files changed, 45 insertions(+)

diff --git a/studio/backend/tests/test_video_backend.py b/studio/backend/tests/test_video_backend.py
index f227c0f40e..e936ca7e94 100644
--- a/studio/backend/tests/test_video_backend.py
+++ b/studio/backend/tests/test_video_backend.py
@@ -8,6 +8,7 @@ stack loads."""
 
 import contextlib
 import sys
+import time
 import types
 
 import pytest
@@ -1107,6 +1108,44 @@ def test_generate_progress_derives_total_steps_and_fraction(fake_runtime):
     assert gen["step"] == 5 and gen["fraction"] == 0.25
 
 
+def test_failed_background_generate_retains_terminal_error(fake_runtime, tmp_path, monkeypatch):
+    # A page mounted AFTER a background job failed (browser reload during a minutes-long
+    # generation) reads the outcome from this retained terminal record -- its only diagnosis,
+    # since nothing else survives the reload. So a failure must stay pollable as
+    # active=False + phase="failed" + error, repeatedly, until the next job replaces it.
+    backend = VideoBackend()
+    _load_gguf(backend, tmp_path)
+
+    def _boom(
+        self,
+        *,
+        prompt = None,
+        negative_prompt = None,
+        num_inference_steps = None,
+        guidance_scale = None,
+        width = None,
+        height = None,
+        num_frames = None,
+        frame_rate = None,
+        generator = None,
+        callback_on_step_end = None,
+        **kwargs,
+    ):
+        raise ValueError("frames exceed the device memory")
+
+    monkeypatch.setattr(type(backend._state.pipe), "__call__", _boom)
+    backend.begin_generate(prompt = "a clip")
+    deadline = time.monotonic() + 10
+    while backend.generate_progress()["active"] and time.monotonic() < deadline:
+        time.sleep(0.01)
+    gen = backend.generate_progress()
+    assert gen["active"] is False
+    assert gen["phase"] == "failed"
+    assert gen["error"] == "frames exceed the device memory"
+    # Re-poll: a mount-time probe is a second read of the same record, not a one-shot drain.
+    assert backend.generate_progress()["phase"] == "failed"
+
+
 def test_cache_bytes_counts_incomplete_blobs(fake_runtime, tmp_path, monkeypatch):
     # scan_cache_dir skips in-flight *.incomplete blobs, so the old counter froze at the
     # last completed blob for the whole multi-GB shard pull. The walk must count both,
diff --git a/studio/frontend/src/features/video/video-page.tsx b/studio/frontend/src/features/video/video-page.tsx
index 2efa7fde6d..291e8e2256 100644
--- a/studio/frontend/src/features/video/video-page.tsx
+++ b/studio/frontend/src/features/video/video-page.tsx
@@ -1002,6 +1002,12 @@ export function VideoPage({ active = true }: { active?: boolean }) {
           const clip = g.video;
           setVideos((prev) => (prev.some((v) => v.id === clip.id) ? prev : [clip, ...prev]));
           void ensureSrc(clip);
+        } else if (g.phase === "failed") {
+          // The other terminal phase, and the backend keeps it only until the next job: without
+          // this a reload after a minutes-long generation failed shows an idle page and the
+          // error (OOM, bad input, disk) is lost. Same cancelled-sentinel filter the poll uses.
+          const msg = g.error || "Video generation failed";
+          if (!msg.toLowerCase().includes("cancelled")) toast.error(msg);
         }
       } catch {
         // Resume is best-effort; a failed probe just leaves the idle view.