CI: stop recurring false failures on main and pull requests

- checks: the runner's packages.microsoft.com apt source now 403s, failing
  `apt-get update` and with it "Install zsh"; tolerate the refresh error
  (Ubuntu's lists still update and the install still fails if it can't).
- e2e: a failed quiet image build is rebuilt with the full log, but the
  script exited 2 even when that rebuild succeeded; only fail if it fails.
- ArtworkTests: a timed-out lookup gives its resolver slot back from its own
  thread, which a busy macOS runner may schedule after the next test starts.
  Wait for every slot before each test, and always return slots a test took,
  so one late thread can't cascade into three failures.
- release: tagged builds no longer re-upload the installers as workflow
  artifacts (they are attached to the release; the artifact finalize timed
  out on v0.3.0). Pull requests build installers only when the Electron app,
  the macOS helper it compiles, or the workflow changes.
- checks and release: a newer push to a pull request cancels the older run.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

.github/workflows/checks.yml

@@ -5,6 +5,11 @@ on:
     branches: [main]
   pull_request:
 
+# A newer push to the same pull request supersedes a run still in progress.
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: ${{ github.event_name == 'pull_request' }}
+
 jobs:
   checks:
     runs-on: ubuntu-latest
@@ -17,7 +22,9 @@ jobs:
         with:
           node-version: "24"
       - name: Install zsh
-        run: sudo apt-get update -qq && sudo apt-get install -y -qq zsh
+        # The runner image's third-party apt sources (packages.microsoft.com) sometimes
+        # fail to refresh; Ubuntu's own lists still update, and the install fails if not.
+        run: (sudo apt-get update -qq || true) && sudo apt-get install -y -qq zsh
       - name: Script syntax
         run: |
           sh -n ui/local-bin/ssh
@@ -84,6 +91,8 @@ jobs:
     steps:
       - uses: actions/checkout@v4
       - name: Install zsh
-        run: sudo apt-get update -qq && sudo apt-get install -y -qq zsh
+        # The runner image's third-party apt sources (packages.microsoft.com) sometimes
+        # fail to refresh; Ubuntu's own lists still update, and the install fails if not.
+        run: (sudo apt-get update -qq || true) && sudo apt-get install -y -qq zsh
       - name: End-to-end tests
         run: scripts/e2e.sh

.github/workflows/release.yml

@@ -2,14 +2,22 @@ name: release
 
 # Pushing a v* tag builds Frame Control for macOS, Windows and Linux and attaches
 # the installers to that tag's GitHub release (created as a draft if missing).
-# Pull requests that touch the app build the same installers as artifacts.
+# Pull requests that change how the installers are built (the Electron app, the
+# macOS helper it compiles, or this workflow) build the same installers as
+# artifacts. ui/, scripts/, frame/ and apk-catalog/ are copied in as they are and
+# are tested by the checks workflow; run this one by hand to package them early.
 on:
   push:
     tags: ["v*"]
   pull_request:
-    paths: ["app/**", "ui/**", "scripts/**", "frame/**", "apk-catalog/**", ".github/workflows/release.yml"]
+    paths: ["app/**", "mac/frame-mac-view/**", ".github/workflows/release.yml"]
   workflow_dispatch:
 
+# A newer push to the same pull request supersedes a build still in progress.
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: ${{ github.event_name == 'pull_request' }}
+
 permissions:
   contents: write
 
@@ -49,7 +57,9 @@ jobs:
           tag="${GITHUB_REF_NAME}"
           gh release view "$tag" >/dev/null 2>&1 || gh release create "$tag" --draft --title "Frame Control ${tag#v}" --notes ""
           gh release upload "$tag" ${{ matrix.files }} --clobber
+      # Tagged builds are attached to the release above; only other builds need artifacts.
       - uses: actions/upload-artifact@v4
+        if: ${{ !startsWith(github.ref, 'refs/tags/') }}
         with:
           name: frame-control-${{ matrix.os }}
           path: |

docs/evidence/linux-vr/2026-09-29.txt

@@ -0,0 +1,29 @@
+Locked real-Frame repeat, 2026-09-29
+SteamOS 0.4.1, BUILD_ID 20260925.6191901; aarch64.
+mkdir /tmp/frame-test.lock succeeded before installs/launches; rmdir issued after cleanup.
+Preflight battery 44%, charging; before WiVRn 46%, before ALVR 47%, cleanup 47%.
+Original Steam PID 49823 and vrserver PID 49571 present after cleanup.
+Same unmodified upstream release APKs and SHA-256s as 2026-09-28.txt.
+Installer functions loaded from a613735 before checkout was fast-forwarded to current main.
+No compatibility layer injected. Per-app immersive Lepton instances, Steam shortcut launches.
+Headset unworn. No Linux gaming host. No pairing or streaming session reached.
+
+WIVRN: selected journal lines (local +1000 prefix, Android timestamps UTC).
+Sep 29 11:03:15 frame lepton-steamlaunch-2817846116[1967]: 09-29 01:03:15.202  1153  1181 E OpenXR-Loader: Error [GENERAL | xrCreateInstance | OpenXR-Loader] : LoaderInstance::CreateInstance, no support found for requested extension: XR_KHR_convert_timespec_time
+Sep 29 11:03:15 frame lepton-steamlaunch-2817846116[1967]: 09-29 01:03:15.210  1153  1181 I WiVRn   : [2026-09-29 01:03:15.210] [WiVRn] [info] Failed to create OpenXR instance version 1.1.58: XR_ERROR_EXTENSION_NOT_PRESENT
+Sep 29 11:03:15 frame lepton-steamlaunch-2817846116[1967]: 09-29 01:03:15.248  1153  1181 E OpenXR-Loader: Error [GENERAL | xrCreateInstance | OpenXR-Loader] : LoaderInstance::CreateInstance, no support found for requested extension: XR_KHR_convert_timespec_time
+Sep 29 11:03:15 frame lepton-steamlaunch-2817846116[1967]: 09-29 01:03:15.256  1153  1181 I WiVRn   : [2026-09-29 01:03:15.256] [WiVRn] [info] Failed to create OpenXR instance version 1.0.58: XR_ERROR_EXTENSION_NOT_PRESENT
+Sep 29 11:03:15 frame lepton-steamlaunch-2817846116[1967]: 09-29 01:03:15.257  1153  1181 E WiVRn   : [2026-09-29 01:03:15.257] [WiVRn] [error] Error during initialization: Failed to create OpenXR instance: XR_ERROR_EXTENSION_NOT_PRESENT
+Screenshot API exit 0; 1920x1080 uniformly dark image; no client scene visible.
+
+ALVR: selected journal lines (local +1000 prefix, Android timestamps UTC).
+Sep 29 11:03:36 frame lepton-steamlaunch-2831623938[1967]: 09-29 01:03:35.553  1139  1167 E OpenXR-Loader: Error [GENERAL | xrCreateInstance | OpenXR-Loader] : LoaderInstance::CreateInstance, no support found for requested extension: XR_KHR_convert_timespec_time
+Sep 29 11:03:36 frame lepton-steamlaunch-2831623938[1967]: 09-29 01:03:35.553  1139  1165 I RustStdoutStderr: Error [GENERAL | xrCreateInstance | OpenXR-Loader] : LoaderInstance::CreateInstance, no support found for requested extension: XR_KHR_convert_timespec_time
+Sep 29 11:03:36 frame lepton-steamlaunch-2831623938[1967]: 09-29 01:03:35.611  1139  1167 E [ALVR NATIVE-RUST]: panicked at alvr/client_openxr/src/lib.rs:220:10:
+Sep 29 11:03:36 frame lepton-steamlaunch-2831623938[1967]: 09-29 01:03:35.611  1139  1167 E [ALVR NATIVE-RUST]: called `Result::unwrap()` on an `Err` value: ERROR_EXTENSION_NOT_PRESENT
+Screenshot API exit 0; 1920x1080 uniformly dark image; no client scene visible.
+
+Cleanup: both test app directories, compatdata, shadercache, containers and shortcuts absent.
+Capture output directory removed. No global settings changed; Steam/SteamVR not stopped.
+The shared lock was subsequently acquired by another thread (new directory timestamp 11:03:49 +1000).
+Native clients and Valve host streaming not exercised: no native build or Linux gaming host available.

docs/linux-vr-streaming.md

@@ -38,6 +38,33 @@ after its container exited. No headset was worn and no host was connected.
 All test app files, compatdata, shortcuts and containers were removed afterwards.
 SteamVR's original process remained running. No global settings changed.
 
+### Locked repeat, 2026-09-29 (verified)
+
+Acquired `/tmp/frame-test.lock` before installing or launching anything and
+released it after cleanup. Battery was 44% and charging at preflight, 46–47%
+during the launches, and 47% at cleanup. The SteamOS version/build was unchanged.
+
+Reinstalled and launched both original APKs in immersive Lepton instances.
+WiVRn again failed at OpenXR 1.1 and 1.0 with the missing timespec extension;
+ALVR again panicked on `ERROR_EXTENSION_NOT_PRESENT`. This repeats the
+unmodified-client test, not the newer installer's automatic compatibility-layer
+path. Neither reached a session that could be paired or exercised further.
+Fresh [journal excerpts and cleanup evidence](evidence/linux-vr/2026-09-29.txt)
+record the failures.
+
+SteamVR's screenshot API returned a 1920×1080 headset capture after each
+launch. Both are uniformly dark: [WiVRn](evidence/linux-vr/2026-09-29-wivrn.png)
+and [ALVR](evidence/linux-vr/2026-09-29-alvr.png). These images do **not** prove
+rendering or a working client. The headset was unworn; visibility, controllers,
+frame rate and motion-to-photon latency could not be judged. The explicit
+OpenXR errors, rather than the dark captures, establish the client blocker.
+
+Both test installs, app data, shader caches, shortcuts, containers and temporary
+capture files were removed. The original Steam and SteamVR process IDs were
+unchanged. No reboot, power action or global setting change was used. Native
+clients remain untested, and no Linux gaming host was available for Valve's
+streaming path. The recommendation below is unchanged.
+
 ### Relation to the VR APK branch
 
 **Documented from source:** [PR #20](https://github.com/saphid/frame-control/pull/20)

scripts/e2e.sh

@@ -23,7 +23,8 @@ started=$SECONDS
 
 print "==> Building fakeframe-frame (from $base) and fakeframe-host"
 # Quiet when it works; if a build fails, build again with the full log so CI shows why.
-build() { docker build -q "$@" >/dev/null || { docker build --progress=plain "$@"; exit 2 } }
+# That second build also rides out a flaky package mirror: only its failure is fatal.
+build() { docker build -q "$@" >/dev/null || docker build --progress=plain "$@" || exit 2 }
 build --build-arg BASE="$base" -t fakeframe-frame -f tests/fakeframe/Containerfile tests/fakeframe
 build -t fakeframe-host -f tests/fakeframe/host.Containerfile tests/fakeframe
 

tests/test_frame_android_library.py

@@ -120,7 +120,27 @@ class LauncherTests(unittest.TestCase):
 FIXTURES = ROOT / 'tests/fixtures/library'
 
 
+def wait_for_idle_resolvers(timeout=10):
+    # Name lookups that outlast their deadline give their slot back from their own thread,
+    # which a busy runner may not schedule before the next test; wait until all are back.
+    from apk_sources import _images
+    held = []
+    try:
+        end = time.monotonic() + timeout
+        while _images._resolvers.acquire(timeout=max(0, end - time.monotonic())):
+            held.append(1)
+            if len(held) == 4:
+                return
+        raise AssertionError('artwork name lookups from an earlier test are still running')
+    finally:
+        for _ in held:
+            _images._resolvers.release()
+
+
 class ArtworkTests(unittest.TestCase):
+    def setUp(self):
+        wait_for_idle_resolvers()
+
     def test_source_inputs_and_url(self):
         from apk_sources import _images
         data = (FIXTURES / 'icon.png').read_bytes()
@@ -231,10 +251,7 @@ class ArtworkTests(unittest.TestCase):
             self.assertEqual(sum('Too many' in e for e in errors), 2)
         finally:
             gate.set()
-        deadline = time.monotonic() + 5
-        while time.monotonic() < deadline and not _images._resolvers.acquire(blocking=False):
-            time.sleep(0.01)
-        _images._resolvers.release()  # the stuck lookups finished and gave their slots back
+        wait_for_idle_resolvers()  # the stuck lookups finished and gave their slots back
 
     def test_resolver_slot_released_when_thread_cannot_start(self):
         from apk_sources import _images
@@ -242,10 +259,14 @@ class ArtworkTests(unittest.TestCase):
             for _ in range(6):
                 with self.assertRaises(RuntimeError):
                     _images.get('https://example.org/a.png', deadline=time.monotonic() + 1)
-        for _ in range(4):  # every slot came back
-            self.assertTrue(_images._resolvers.acquire(blocking=False))
-        for _ in range(4):
-            _images._resolvers.release()
+        held = 0
+        try:
+            while held < 4 and _images._resolvers.acquire(blocking=False):
+                held += 1
+            self.assertEqual(held, 4)  # every slot came back
+        finally:
+            for _ in range(held):  # even on failure, so later tests don't inherit the leak
+                _images._resolvers.release()
 
     def test_deadline_covers_name_resolution(self):
         import threading