Fix single-instance mutex race during app restart handoff - #50
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Settings "Save & Restart" starts the replacement iMirror process before the old process finishes disconnecting and shutting down. The new process could lose the single-instance mutex race and silently exit, leaving the user with no running iMirror. App.Main now waits up to 5 seconds for the previous holder to release the mutex (via SingleInstanceGate), treating an abandoned mutex as a successful acquire. Genuine duplicate launches still exit, just after a bounded wait. Adds 5 SingleInstanceGate tests covering unowned, held, released-within-timeout, and abandoned mutex cases. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
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Problem
RestartApplicationAsync(settings "Save & Restart") starts the replacement process before the old process finishesShutdownApplicationAsync(disconnect, tray dispose,Application.Shutdown).App.Mainexits immediately when the single-instance mutex is already held, so the relaunched instance could silently quit while the old one was still shutting down — the restart button would just close the app.Fix
SingleInstanceGate.TryAcquireExistingMutex: boundedWaitOnethat treatsAbandonedMutexException(previous process died without releasing) as a successful acquire.App.Mainnow waits up to 5 seconds for the previous instance to release the mutex before giving up. Genuine duplicate launches still exit as before, after the bounded wait. Both paths are logged.No change to update/installer handoff behavior: the Inno Setup
/CLOSEAPPLICATIONSrelaunch path already waits for the old process to exit, and it also benefits from the extra tolerance.Testing
5 new
SingleInstanceGateTestscover: unowned mutex, mutex held past the timeout (returns false), holder releasing within the timeout, abandoned mutex, and null argument.Validation
dotnet build iMirror.sln -c Release— passed, 0 warnings, 0 errors.dotnet test MacMirrorReceiver.Tests\MacMirrorReceiver.Tests.csproj -c Release— passed: 72 tests, 0 failed.Independent of #49; can merge in any order (trivial CHANGELOG adjacency with other Unreleased entries).
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