build: pin the frontend builder image to the last QEMU-safe digest

Docker Hub rebuilt node:22-alpine on 2026-09-17 with the same Node
(22.23.2) but refreshed Alpine layers. That rebuild dies under QEMU while
cross-building the arm64 leg: `qemu: uncaught target signal 4 (Illegal
instruction)`, exit 132, during `pnpm install`.

Three consecutive release builds failed identically on it. Every other
input was unchanged and verified by digest — runner image 20260907.300.1,
tonistiigi/binfmt sha256:400a4873, pnpm pinned at 11.5.2, lockfile
untouched — and quality-checks, which runs natively, passed every time.
The tag was the only floating input:

  last green build 09-15  node:22-alpine@sha256:c610fcdf  built 2026-07-29
  failing         09-20   node:22-alpine@sha256:b6f26b36  built 2026-09-17

Pinned to the older of the two. It ships nothing: the builder stage is
discarded and only ui/dist is copied out, so no Alpine bytes reach the
runtime image and holding an older base costs no exposure.

This is a stopgap for the emulated build, not a fix for it. The durable
answer is building the arm64 leg on a native runner, which removes the
whole failure class.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

Dockerfile

@@ -2,7 +2,19 @@
 # has lagged behind and resolved to a Node patch older than the Angular CLI's
 # minimum supported version, breaking the build. node:22-alpine currently
 # satisfies @angular/cli's >=22.22.3 requirement.
-FROM node:22-alpine AS builder
+#
+# Pinned further, to a digest: Docker Hub rebuilt node:22-alpine on 2026-09-17
+# with the same Node (22.23.2) but refreshed Alpine layers, and that rebuild
+# dies under QEMU while cross-building the arm64 leg — `qemu: uncaught target
+# signal 4 (Illegal instruction)`, exit 132, during `pnpm install`. Three
+# consecutive release builds failed identically on it while every other input
+# (runner image, binfmt digest, pnpm version, lockfile) was unchanged.
+#
+# This digest is the last image known to cross-build cleanly (built 2026-07-29).
+# It ships nothing: this stage is thrown away and only ui/dist is copied out.
+# Unpin once the arm64 leg builds natively instead of under emulation, or once
+# a later node:22-alpine is confirmed to survive QEMU.
+FROM node:22-alpine@sha256:c610fcdfb1d5b4740dd70c284ed3cb16bb857e0f7166196e36a5501df7a3aa32 AS builder
 
 WORKDIR /metube
 COPY ui ./

app/tests/test_download_queue.py

@@ -2,6 +2,7 @@
 
 from __future__ import annotations
 
+import asyncio
 import copy
 import os
 import re
@@ -311,6 +312,47 @@ async def test_start_pending_moves_to_queue(dq_env):
     with patch.object(DownloadQueue, "_DownloadQueue__start_download", AsyncMock()):
         await dq.start_pending([url])
     assert not dq.pending.exists(url)
+    # It is in the queue now and starts on its own, so it must not keep
+    # advertising the Start button the UI draws for 'pending' (#1081), and the
+    # client has to be told before the concurrency slot frees up.
+    assert dq.queue.get(url).info.status == "queued"
+    assert notifier.updated.await_args[0][0].status == "queued"
+
+
+@pytest.mark.asyncio
+async def test_queued_download_is_not_offered_as_startable(dq_env):
+    """A download waiting on a MAX_CONCURRENT_DOWNLOADS slot used to sit at
+    'pending', which is the status the UI draws a Start button for — but
+    start_pending has nothing to do for an item already in the queue, so the
+    button silently did nothing and still reported success (#1081).
+    """
+    notifier = AsyncMock()
+    dq_env.MAX_CONCURRENT_DOWNLOADS = "1"
+    dq = DownloadQueue(dq_env, notifier)
+    released = asyncio.Event()
+
+    def fake_extract(self, url, *_args, **_kwargs):
+        return {"_type": "video", "id": url[-1], "title": f"Video {url[-1]}",
+                "url": url, "webpage_url": url}
+
+    async def blocking_start(self, notifier_, executor=None):
+        await released.wait()
+
+    first, second = "https://example.com/v1", "https://example.com/v2"
+    with patch.object(DownloadQueue, "_DownloadQueue__extract_info", fake_extract), \
+         patch("ytdl.Download.start", blocking_start), \
+         patch("ytdl.Download.close", lambda self: None):
+        for url in (first, second):
+            await dq.add(url, "video", "auto", "any", "best", "", "", 0, auto_start=True)
+        await asyncio.sleep(0)
+
+        # The first holds the only slot; the second is waiting behind it.
+        assert dq.queue.get(second).info.status == "queued"
+        assert not dq.pending.exists(second)
+
+        released.set()
+
+    await asyncio.sleep(0)
 
 
 @pytest.mark.asyncio
@@ -1200,7 +1242,7 @@ async def test_probe_scheduled_starts_when_live(dq_env):
 
     assert url not in dq._scheduled_probe_at
     assert download.info.live_status == "is_live"
-    assert download.info.status == "pending"
+    assert download.info.status == "queued"
     start_mock.assert_called_once_with(download)
 
 
@@ -1345,7 +1387,7 @@ async def test_probe_recovers_after_transient_then_starts(dq_env):
 
     assert url not in dq._scheduled_probe_at
     assert url not in dq._scheduled_probe_failures
-    assert download.info.status == "pending"
+    assert download.info.status == "queued"
     # Placeholder error/msg cleared now that a real download is starting.
     assert download.info.error is None
     assert download.info.msg is None

app/ytdl.py

@@ -495,6 +495,12 @@ class DownloadInfo:
         self.folder = folder
         self.custom_name_prefix = custom_name_prefix
         self.msg = self.percent = self.speed = self.eta = None
+        # 'pending' means "waiting for the user to press Start" — an item added
+        # with auto_start=False, sitting in self.pending. A download that is in
+        # self.queue waiting for a MAX_CONCURRENT_DOWNLOADS slot is 'queued'
+        # instead: it starts on its own and there is nothing to press. Keeping
+        # both under one name left the UI showing a Start button that silently
+        # did nothing (#1081).
         self.status = "pending"
         self.size = None
         self.timestamp = time.time_ns()
@@ -1484,7 +1490,7 @@ class DownloadQueue:
             return
 
         self._unregister_scheduled(url)
-        info.status = 'pending'
+        info.status = 'queued'
         # Clear the "scheduled to start at ..." placeholder now that the stream
         # is live and a real download is about to begin.
         info.error = None
@@ -1499,7 +1505,7 @@ class DownloadQueue:
 
     def _force_start_scheduled(self, download: Download) -> None:
         self._unregister_scheduled(download.info.url)
-        download.info.status = 'pending'
+        download.info.status = 'queued'
         download.info.error = None
         download.info.msg = None
         bg_tasks.create_task(self.__start_download(download), name="start_download")
@@ -1649,6 +1655,7 @@ class DownloadQueue:
             if is_upcoming:
                 await self._schedule_upcoming_download(download)
             else:
+                download.info.status = 'queued'
                 await self.queue.put(download)
                 bg_tasks.create_task(self.__start_download(download), name="start_download")
         else:
@@ -2159,7 +2166,13 @@ class DownloadQueue:
                 if getattr(dl.info, 'live_status', None) == 'is_upcoming':
                     await self._schedule_upcoming_download(dl)
                 else:
+                    dl.info.status = 'queued'
                     await self.queue.put(dl)
+                    # Tell the client it moved out of 'pending' now, not when a
+                    # slot frees up: with MAX_CONCURRENT_DOWNLOADS saturated the
+                    # wait is unbounded, and until this lands the row still
+                    # offers the Start button it has already outgrown.
+                    await self.notifier.updated(dl.info)
                     bg_tasks.create_task(self.__start_download(dl), name="start_download")
                 continue
             if self.queue.exists(id):

ui/src/app/app.html

@@ -728,6 +728,9 @@
                     @if (download.value.live_status === 'is_live' && download.value.status !== 'scheduled') {
                       <span class="badge bg-danger">LIVE</span>
                     }
+                    @if (download.value.status === 'queued') {
+                      <span class="badge bg-secondary">Queued</span>
+                    }
                   </div>
                   @if (download.value.status === 'scheduled') {
                     <span class="badge bg-warning text-dark">
@@ -751,7 +754,7 @@
               <td>{{ download.value.speed | speed }}</td>
               <td>{{ download.value.eta | eta }}</td>
               <td>
-                <div class="d-flex">
+                <div class="d-flex justify-content-end">
                   @if (download.value.status === 'pending' || download.value.status === 'scheduled') {
                     <button type="button" class="btn btn-link" [attr.aria-label]="'Start download for ' + download.value.title" (click)="downloadItemByKey(download.key)"><fa-icon [icon]="faDownload" /></button>
                   }
@@ -878,7 +881,7 @@
                 }
               </td>
               <td>
-                <div class="d-flex">
+                <div class="d-flex justify-content-end">
                   @if (entry[1].status === 'error') {
                     <button type="button" class="btn btn-link" [attr.aria-label]="'Retry download for ' + entry[1].title" (click)="retryDownload(entry[0], entry[1])"><fa-icon [icon]="faRedoAlt" /></button>
                   }

ui/src/app/app.spec.ts

@@ -544,4 +544,57 @@ describe('App', () => {
     });
   });
 
+  // Issue #1081: a download waiting for a concurrency slot ('queued') starts on
+  // its own, so it must not offer the Start button that a 'pending' row — one
+  // added with auto-start off — legitimately has.
+  describe('queued rows do not offer a dead Start button (#1081)', () => {
+    const queueEntry = (status: string): Download => ({
+      id: 'vid1',
+      title: 'Test',
+      url: 'https://example.com/v',
+      download_type: 'video',
+      quality: 'best',
+      format: 'any',
+      folder: '',
+      custom_name_prefix: '',
+      playlist_item_limit: 0,
+      status,
+      msg: '',
+      percent: 0,
+      speed: 0,
+      eta: 0,
+      filename: '',
+      checked: false,
+    } as Download);
+
+    const render = (status: string) => {
+      const fixture = TestBed.createComponent(App);
+      downloads.queue.set('https://example.com/v', queueEntry(status));
+      downloads.queueChanged.next();
+      fixture.detectChanges();
+      return fixture;
+    };
+
+    it('hides Start for a queued row but keeps it for a pending one', () => {
+      const queued = render('queued');
+      expect(
+        (queued.nativeElement as HTMLElement).querySelector('[aria-label="Start download for Test"]')
+      ).toBeNull();
+
+      downloads.queue.clear();
+
+      const pending = render('pending');
+      expect(
+        (pending.nativeElement as HTMLElement).querySelector('[aria-label="Start download for Test"]')
+      ).not.toBeNull();
+    });
+
+    it('says why the row is idle and counts it as queued', () => {
+      const fixture = render('queued');
+      expect((fixture.nativeElement as HTMLElement).textContent).toContain('Queued');
+      expect(fixture.componentInstance.queuedDownloads).toBe(1);
+      expect(fixture.componentInstance.activeDownloads).toBe(0);
+    });
+  });
+
 });

ui/src/app/app.ts

@@ -1728,7 +1728,7 @@ export class App implements AfterViewInit, OnInit, OnDestroy {
         speed += download.speed || 0;
       } else if (download.status === 'preparing' || download.status === 'postprocessing') {
         active++;
-      } else if (download.status === 'pending' || download.status === 'scheduled') {
+      } else if (download.status === 'queued' || download.status === 'pending' || download.status === 'scheduled') {
         queued++;
       }
     });