Reported 2026-09-27: click avatar -> Change Account -> cancel in the Google
chooser -> back to a signed-out app, then "cannot sign-in because the callback
url was not released".
Two independent defects:
1. ChangeAccountAsync ran `await SignOutYouTubeAsync(); await SignInAsync();`.
SignOutYouTubeAsync -> TokenStore.Clear() -> deletes ytLlive.auth, so the
working account's token was destroyed before the browser even opened. It is
now just `await SignInAsync()`: success overwrites the token via the
sessionChanged hook, cancel/failure keeps the current session. The explicit
sign-out was never needed.
2. Abandoning the browser gives the app no signal, so the OAuth attempt held
localhost:8765 for its full 5-minute timeout and a retry could not bind. A
new AuthenticateAsync now cancels and awaits the abandoned attempt first.
That takeover is serialised by a SemaphoreSlim: the first version cleared
the in-flight marker before awaiting, so a caller arriving in that window saw
a free port and raced to bind it -- reproducing the very failure it was
written to prevent. My own test caught that; reasoning had "proved" it fine.
Also adds an `openBrowser` ctor seam so tests never shell out to a real
browser, and corrects the ai.md line that documented "Logout / Change Account ->
SignOutYouTubeAsync" as intended behaviour.
Test: YouTubeAuthServiceTests.RetryingAfterAnAbandonedAttempt_ReleasesTheCallbackPort
Full suite 370/370, 0 warnings. Coverage gap noted in HANDOFF.md: the ordering
fix has no automated test because _youtubeAuth is hardcoded in MainViewModel
and ChangeAccountAsync is private.
The reported cross-instance effect is NOT this cause and stays open -- no code
path can sign out a second instance (per-instance TokenStore, local delete, no
server-side revoke).
Software compositor that renders a scene into the encoder's master VideoFrame,
mirroring the XAML preview minus editing chrome: backdrop -> background ->
elements (UniformToFill cover-crop, round clip, mirror, opacity, border) ->
branding flash.
NOTE FOR USERS: this change shows NO difference in the app's UI — it is pure
backend scaffolding laying the groundwork for live video capture/streaming.
The preview you see is unchanged.
- Services/Compositor/: SceneCompositor (Render(scene, frameFor resolver,
flashFrame, CompositorOptions)), CompositorOptions (source rect + output
size; 16:9 full master, vertical 607x1080 -> 1080x1920), StretchMath (pure
UniformToFill + bilinear), StaticPixelCache (asset bytes -> BGRA8 frame)
- Frame sources injected via Func<SceneElement, VideoFrame?> resolver, so the
compositor is pure, WPF-free, and hermetic to test (D3D11 upgrade behind the
same seam later)
- SceneElement.TryGetBorderColor public (shared hex parse), stale
MainViewModel comment fixed, pre-existing CS1998 in YouTubeAuthServiceTests
cleaned up
- Tests: SceneCompositorTests integration (full scene + vertical tier + flash)
+ StretchMath units, docs updated (72 tests passing, 0 warnings)
gramps