Merge pull request #359 from dotnet/copilot/fix-emulator-boot-error

Handle InvalidOperationException in emulator boot and improve Process disposal

Author: simonrozsival

src/Xamarin.Android.Tools.AndroidSdk/Runners/EmulatorRunner.cs

@@ -85,7 +85,10 @@ public Process LaunchEmulator (string avdName, bool coldBoot = false, List<strin
 logger.Invoke(TraceLevel.Warning,$"[emulator] {e.Data}");
 };
 
-process.Start();
+if(!process.Start()){
+process.Dispose();
+thrownewInvalidOperationException($"Failed to start emulator process '{emulatorPath}'.");
+}
 
 // Drain redirected streams asynchronously to prevent pipe buffer deadlocks
 process.BeginOutputReadLine();
@@ -209,51 +212,59 @@ public async Task<EmulatorBootResult> BootEmulatorAsync (
 // code 0 immediately. The real emulator continues as a separate process and
 // will eventually appear in 'adb devices'. We only treat non-zero exit codes
 // as immediate failures; exit code 0 means we continue polling.
-try{
-string?newSerial=null;
-boolprocessExitedWithZero=false;
-while(newSerial==null){
-timeoutCts.Token.ThrowIfCancellationRequested();
-
-// Detect early process exit for fast failure
-if(emulatorProcess.HasExited&&!processExitedWithZero){
-if(emulatorProcess.ExitCode!=0){
-emulatorProcess.Dispose();
+//
+// Dispose the Process handle when done — the emulator process keeps running.
+using(emulatorProcess){
+try{
+string?newSerial=null;
+boolprocessExitedWithZero=false;
+while(newSerial==null){
+timeoutCts.Token.ThrowIfCancellationRequested();
+
+// Detect early process exit for fast failure.
+// Guard against InvalidOperationException in case no OS process
+// is associated with the object (e.g. broken emulator binary).
+try{
+if(emulatorProcess.HasExited&&!processExitedWithZero){
+if(emulatorProcess.ExitCode!=0){
+returnnewEmulatorBootResult{
+Success=false,
+ErrorKind=EmulatorBootErrorKind.LaunchFailed,
+ErrorMessage=$"Emulator process for '{deviceOrAvdName}' exited with code {emulatorProcess.ExitCode} before becoming available.",
+};
+}
+// Exit code 0: emulator likely forked (common on macOS).
+// The real emulator runs as a separate process — keep polling.
+logger.Invoke(TraceLevel.Verbose,$"Emulator launcher process exited with code 0 (likely forked). Continuing to poll adb devices.");
+processExitedWithZero=true;
+}
+}catch(InvalidOperationExceptionex){
 returnnewEmulatorBootResult{
 Success=false,
 ErrorKind=EmulatorBootErrorKind.LaunchFailed,
-ErrorMessage=$"Emulator process for '{deviceOrAvdName}' exited with code {emulatorProcess.ExitCode} before becoming available.",
+ErrorMessage=$"Emulator process for '{deviceOrAvdName}' is no longer available: {ex.Message}",
 };
 }
-// Exit code 0: emulator likely forked (common on macOS).
-// The real emulator runs as a separate process — keep polling.
-logger.Invoke(TraceLevel.Verbose,$"Emulator launcher process exited with code 0 (likely forked). Continuing to poll adb devices.");
-processExitedWithZero=true;
-}
-
-awaitTask.Delay(options.PollInterval,timeoutCts.Token).ConfigureAwait(false);
 
-devices=awaitadbRunner.ListDevicesAsync(timeoutCts.Token).ConfigureAwait(false);
-newSerial=FindRunningAvdSerial(devices,deviceOrAvdName);
-}
+awaitTask.Delay(options.PollInterval,timeoutCts.Token).ConfigureAwait(false);
 
-logger.Invoke(TraceLevel.Info,$"Emulator appeared as '{newSerial}', waiting for full boot...");
-varresult=awaitWaitForFullBootAsync(adbRunner,newSerial,options,timeoutCts.Token).ConfigureAwait(false);
+devices=awaitadbRunner.ListDevicesAsync(timeoutCts.Token).ConfigureAwait(false);
+newSerial=FindRunningAvdSerial(devices,deviceOrAvdName);
+}
 
-// Release the Process handle — the emulator process itself keeps running.
-// We no longer need stdout/stderr forwarding since boot is complete.
-emulatorProcess.Dispose();
-returnresult;
-}catch(OperationCanceledException)when(!cancellationToken.IsCancellationRequested){
-TryKillProcess(emulatorProcess);
-returnnewEmulatorBootResult{
-Success=false,
-ErrorKind=EmulatorBootErrorKind.Timeout,
-ErrorMessage=$"Timed out waiting for emulator '{deviceOrAvdName}' to boot within {options.BootTimeout.TotalSeconds}s.",
-};
-}catch{
-TryKillProcess(emulatorProcess);
-throw;
+logger.Invoke(TraceLevel.Info,$"Emulator appeared as '{newSerial}', waiting for full boot...");
+returnawaitWaitForFullBootAsync(adbRunner,newSerial,options,timeoutCts.Token).ConfigureAwait(false);
+}catch(OperationCanceledException)when(!cancellationToken.IsCancellationRequested){
+TryKillProcess(emulatorProcess);
+returnnewEmulatorBootResult{
+Success=false,
+ErrorKind=EmulatorBootErrorKind.Timeout,
+ErrorMessage=$"Timed out waiting for emulator '{deviceOrAvdName}' to boot within {options.BootTimeout.TotalSeconds}s.",
+};
+}catch{
+TryKillProcess(emulatorProcess);
+throw;
+}
 }
 }
 
@@ -276,8 +287,6 @@ void TryKillProcess (Process process)
 }catch(Exceptionex){
 // Best-effort: process may have already exited
 logger.Invoke(TraceLevel.Verbose,$"Failed to stop emulator process: {ex.Message}");
-}finally{
-process.Dispose();
 }
 }
 

tests/Xamarin.Android.Tools.AndroidSdk-Tests/EmulatorRunnerTests.cs

@@ -480,6 +480,38 @@ public void BootEmulatorAsync_EmptyDeviceName_Throws ()
 runner.BootEmulatorAsync("",mockAdb));
 }
 
+[Test]
+publicasyncTaskInvalidEmulatorBinary_ReturnsLaunchFailed()
+{
+var(tempDir,emuPath)=CreateFakeEmulatorSdk();
+
+// Overwrite with a script that exits immediately with error code 1
+if(OS.IsWindows){
+File.WriteAllText(emuPath,"@echo off\r\nexit /b 1\r\n");
+}else{
+File.WriteAllText(emuPath,"#!/bin/sh\nexit 1\n");
+}
+
+try{
+vardevices=newList<AdbDeviceInfo>();
+varmockAdb=newMockAdbRunner(devices);
+
+varrunner=newEmulatorRunner(emuPath);
+varoptions=newEmulatorBootOptions{
+BootTimeout=TimeSpan.FromSeconds(5),
+PollInterval=TimeSpan.FromMilliseconds(50),
+};
+
+varresult=awaitrunner.BootEmulatorAsync("Test_AVD",mockAdb,options);
+
+Assert.IsFalse(result.Success);
+Assert.AreEqual(EmulatorBootErrorKind.LaunchFailed,result.ErrorKind);
+Assert.That(result.ErrorMessage,Does.Contain("exited with code"));
+}finally{
+Directory.Delete(tempDir,true);
+}
+}
+
 // --- Helpers ---
 
 static(stringtempDir,stringemulatorPath)CreateFakeEmulatorSdk()