[debugging] Retry JDWP process lookup

src/Xamarin.AndroidTools/AssemblyInfo.cs

@@ -30,3 +30,4 @@
 	"00240000048000009400000006020000002400005253413100040000010001008B63AA15D5222FA8E77F9DBFBE47AD82E74130B737743BC5" +
 	"2A7074AD85D2EB34F28C83EFD0C1812C6957BAED24836300DF569EA0E6A71EEDA71C5E88A657AB8F243F268DA584B2D4EF4FCD3245B6A370" +
 	"001A77DE21DE670E4678E29942F5628B153E88CD19504664FC663F9729DCA1CA2977875710EAF2CBD382DD6FD52BE9D3")]
+[assembly: InternalsVisibleTo ("Xamarin.Android.Tools.AndroidSdk-Tests, PublicKey=0024000004800000940000000602000000240000525341310004000011000000438ac2a5acfbf16cbd2b2b47a62762f273df9cb2795ceccdf77d10bf508e69e7a362ea7a45455bbf3ac955e1f2e2814f144e5d817efc4c6502cc012df310783348304e3ae38573c6d658c234025821fda87a0be8a0d504df564e2c93b2b878925f42503e9d54dfef9f9586d9e6f38a305769587b1de01f6c0410328b2c9733db")]

src/Xamarin.AndroidTools/Debugging/DebuggingExtensions.cs

@@ -20,6 +20,8 @@ namespace Xamarin.AndroidTools.Debugging
 	/// </summary>
 	public static class DebuggingExtensions
 	{
+		// Twenty retries at 250 ms intervals allow up to five seconds for the process to appear.
+		const int GET_PID_RETRY_COUNT = 20;
 		const int WAIT_BEFORE_RETRY_GET_PID = 250;
 		const int WAIT_FOR_DEBUGGER_TO_ATTACH_MS = 1400;
 
@@ -58,14 +60,8 @@ public async static Task StartWithDebuggingAsync(this IAndroidDevice device, Exe
 			}
 
 			await androidDevice.ExecuteIntentCommandAsync(configuration.RunCommand, configuration.LogWiter, token).ConfigureAwait(false);
-			if (javaDebugging) {
-				try {
-					await androidDevice.ConnectJdwpAsync (configuration, token).ConfigureAwait(false);
-				} catch (Exception ex) {
-					if (configuration.LogWiter != null)
-						configuration.LogWiter ($"warning: Could not connect Jdwp. {ex}");
-				}
-			}
+			if (javaDebugging)
+				await androidDevice.ConnectJdwpAsync (configuration, token).ConfigureAwait(false);
 		}
 
 		/// <summary>
@@ -173,29 +169,27 @@ public static bool IsWSA(this AndroidDevice androidDevice)
 
 		public static async Task ConnectJdwpAsync(this AndroidDevice androidDevice, ExecutionConfiguration config, CancellationToken token)
 		{
-			if (config.RunCommand != null && config.RunCommand is AmStartCommand amStartCommand && amStartCommand.EnableDebugging)
+			if (config.RunCommand is AmStartCommand amStartCommand && amStartCommand.EnableDebugging)
 			{
-				var packageName = (config.RunCommand as AmStartCommand).PackageName;
-				var pid = await androidDevice.GetProcessIDAsync(packageName, 5, WAIT_BEFORE_RETRY_GET_PID, token);
+				var packageName = amStartCommand.PackageName;
+				var pid = await androidDevice.GetProcessIDAsync (packageName, GET_PID_RETRY_COUNT, WAIT_BEFORE_RETRY_GET_PID, token).ConfigureAwait (false);
 
 				if (pid <= 0)
-				{
-					throw new Exception("Process Not Found.");
-				}
-
-				var jdwpClient = new JdwpClient(config.Debugger.JdwpHostName, config.Debugger.JdwpPort);
+					throw new InvalidOperationException ($"Could not find process for package '{packageName}'.");
 
-				await AdbServer.Default.ForwardPort(androidDevice, "tcp", jdwpClient.Port, "jdwp", pid, token);
-				try {
-					await jdwpClient.ConnectAsync (token);
+				using (var jdwpClient = new JdwpClient (config.Debugger.JdwpHostName, config.Debugger.JdwpPort)) {
+					await AdbServer.Default.ForwardPort (androidDevice, "tcp", jdwpClient.Port, "jdwp", pid, token);
+					try {
+						await jdwpClient.ConnectAsync (token);
 
-					// Keep the Connection for 1300 milliseconds, otherwise the Android OS ignores the connection!
-					// https://github.com/aosp-mirror/platform_frameworks_base/blob/6b28a227400749f4f8ad1f56799370e7c2cab149/core/java/android/os/Debug.java#L101C50-L101C54
-					await Task.Delay (WAIT_FOR_DEBUGGER_TO_ATTACH_MS);
+						// Keep the Connection for 1300 milliseconds, otherwise the Android OS ignores the connection!
+						// https://github.com/aosp-mirror/platform_frameworks_base/blob/6b28a227400749f4f8ad1f56799370e7c2cab149/core/java/android/os/Debug.java#L101C50-L101C54
+						await Task.Delay (WAIT_FOR_DEBUGGER_TO_ATTACH_MS, token);
 
-					await jdwpClient.DisconnectAsync ();
-				} finally {
-					await AdbServer.Default.KillForward (androidDevice, "tcp", jdwpClient.Port, token);
+						await jdwpClient.DisconnectAsync ();
+					} finally {
+						await AdbServer.Default.KillForward (androidDevice, "tcp", jdwpClient.Port, CancellationToken.None);
+					}
 				}
 			}
 		}

src/Xamarin.AndroidTools/Devices/AndroidDeviceExtensions.cs

@@ -144,15 +144,20 @@ static Task KillProcessAndWaitForExitPreIcs (AndroidDevice device, string packag
 	}
 
 	public static async Task<int> GetProcessIDAsync(this AndroidDevice device, string packageName, int maxAttempts, int timeBetweenAttempts, CancellationToken token)
+	{
+		return await GetProcessIDAsync (cancellationToken => device.GetProcessId (packageName, cancellationToken), maxAttempts, timeBetweenAttempts, token);
+	}
+
+	internal static async Task<int> GetProcessIDAsync (Func<CancellationToken, Task<int>> getProcessId, int maxAttempts, int timeBetweenAttempts, CancellationToken token)
 	{
 		var retryCount = 1;
-		var pidOfResult = await device.GetProcessId(packageName, token);
+		var pidOfResult = await getProcessId (token);
 		AndroidLogger.LogDebug("GetProcessIDAsync", "PID of the application :: " + pidOfResult);
 
 		while (pidOfResult <= 0 && retryCount <= maxAttempts)
 		{
-			await Task.Delay(timeBetweenAttempts);
-			pidOfResult = await device.GetProcessId(packageName, token);
+			await Task.Delay(timeBetweenAttempts, token);
+			pidOfResult = await getProcessId (token);
 			AndroidLogger.LogDebug("GetProcessIDAsync", "Retrying " + retryCount + " time(s) to get PID of the application");
 			retryCount++;
 		}

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

@@ -0,0 +1,60 @@
+using System.Collections.Generic;
+using System.Threading;
+using System.Threading.Tasks;
+using NUnit.Framework;
+
+namespace Xamarin.Android.Tools.Tests;
+
+[TestFixture]
+public class AndroidDeviceExtensionsTests
+{
+	[Test]
+	public async Task GetProcessIDAsyncRetriesUntilProcessAppears ()
+	{
+		var processIds = new Queue<int> (new [] { 0, 0, 1234 });
+
+		var processId = await AndroidDeviceExtensions.GetProcessIDAsync (
+			_ => Task.FromResult (processIds.Dequeue ()),
+			maxAttempts: 20,
+			timeBetweenAttempts: 0,
+			token: CancellationToken.None
+		);
+
+		Assert.AreEqual (1234, processId);
+		Assert.AreEqual (0, processIds.Count);
+	}
+
+	[Test]
+	public async Task GetProcessIDAsyncStopsAfterMaximumAttempts ()
+	{
+		var attempts = 0;
+
+		var processId = await AndroidDeviceExtensions.GetProcessIDAsync (
+			_ => {
+				attempts++;
+				return Task.FromResult (0);
+			},
+			maxAttempts: 2,
+			timeBetweenAttempts: 0,
+			token: CancellationToken.None
+		);
+
+		Assert.AreEqual (0, processId);
+		Assert.AreEqual (3, attempts);
+	}
+
+	[Test]
+	public void GetProcessIDAsyncHonorsCancellation ()
+	{
+		using (var cancellationTokenSource = new CancellationTokenSource ()) {
+			cancellationTokenSource.Cancel ();
+
+			Assert.ThrowsAsync<TaskCanceledException> (() => AndroidDeviceExtensions.GetProcessIDAsync (
+				_ => Task.FromResult (0),
+				maxAttempts: 20,
+				timeBetweenAttempts: 1,
+				token: cancellationTokenSource.Token
+			));
+		}
+	}
+}

tests/Xamarin.Android.Tools.AndroidSdk-Tests/Xamarin.Android.Tools.AndroidSdk-Tests.csproj

@@ -26,6 +26,7 @@
 
   <ItemGroup>
     <ProjectReference Include="..\..\src\Xamarin.Android.Tools.AndroidSdk\Xamarin.Android.Tools.AndroidSdk.csproj" />
+    <ProjectReference Include="..\..\src\Xamarin.AndroidTools\Xamarin.AndroidTools.csproj" />
   </ItemGroup>
 
 </Project>