Public Access
jaap-jan
ef12e8cc99
CI went red on the run that added the renderer tests, and not on anything they assert: TerminalDataPlaneTests.Output_ReachesTheRenderer read the output frame where it expected the session's opening one, having lost a race that has been in the helper since it was written. Connected and attached are two different moments. ClientWebSocket.ConnectAsync completes on the 101, which UpgradeAsync writes before it has a WebSocket to attach — it builds one from the stream and swaps it in a few instructions later, on the accept thread. SendAsync drops anything sent in between, which is the transport's documented contract rather than a bug: there is nowhere to put a frame for a renderer that is not there, and queueing it is the unbounded growth the credit window exists to prevent. So a helper that returned on the handshake and let its caller send immediately was betting on thread scheduling, every run, on every test in the file. It only started losing now because that assembly grew nine tests and a JavaScript engine to run them in, which is more work in parallel with a window measured in instructions. The race is older than the branch that exposed it. ConnectAsync now waits for the plane's own SocketAttached, subscribed before the connection because the event can be over before ConnectAsync returns, and bounded so a socket that never attaches fails the helper instead of hanging the suite in a later receive. TerminalWorkspaceTests.ConnectRendererAsync has the same exposure through OpenSessionAsync's opening frame and now waits on WaitForRendererAsync, with a note on why that is enough for the reattach tests and what would stop being enough. ◆ NOTHING IN src CHANGED, AND THAT IS THE CONCLUSION RATHER THAN THE SHORTCUT. Production waits for exactly this moment already — every path that opens a session goes through TerminalWorkspace.WaitForRendererAsync, which resolves from the same few lines that raise the event this helper now waits on. Only the tests skipped the gate the application does not. Verified by widening the window rather than by hunting the flake: a 100ms delay inserted between the 101 and the attach, in a throwaway tree, hangs the old helper outright — both frames dropped, the test blocked in receive — and passes 89/89 with this one. Green three times over on the CI platform besides (Alpine, musl, Release, dotnet/sdk:10.0-alpine).