[tools] Add a tool to launch processes disclaming responsibility.

tests/common/shared-dotnet.mk

@@ -61,6 +61,8 @@ include $(TOP)/mk/colors.mk
 
 unexport MSBUILD_EXE_PATH
 
+SPAWNER?=$(TOP)/tools/spawner/spawner
+
 BINLOG_TIMESTAMP:=$(shell date +%Y-%m-%d-%H%M%S)
 
 ifeq ($(TESTNAME),)
@@ -202,7 +204,7 @@ delete-saved-state:
 run-bare: export RUNTIMEIDENTIFIER=
 run-bare: export RUNTIMEIDENTIFIERS=
 run-bare: delete-saved-state
-	$(Q) $(EXECUTABLE) --autostart --autoexit $(RUN_ARGUMENTS)
+	$(Q) $(SPAWNER) $(EXECUTABLE) --autostart --autoexit $(RUN_ARGUMENTS)
 	$(Q) $(MAKE) delete-saved-state
 
 # Get the list of applicable simulators, and pick the first in the list.

tests/monotouch-test/AudioToolbox/AudioConverterTest.cs

@@ -167,10 +167,11 @@ public void ConvertWithPacketDependencies (AudioFormatType targetType)
 			TestRuntime.AssertXcodeVersion (26, 0);
 
 			var sourcePath = Path.Combine (NSBundle.MainBundle.ResourcePath, "Hand.wav");
-			var paths = NSSearchPath.GetDirectories (NSSearchPathDirectory.DocumentDirectory, NSSearchPathDomain.User);
 
-			var output1 = Path.Combine (paths [0], "output1.caf");
-			Convert (sourcePath, output1, targetType, withPacketDependencies: true);
+			DoWithTemporaryDirectory ((temporaryDirectory) => {
+				var output1 = Path.Combine (temporaryDirectory, "output1.caf");
+				Convert (sourcePath, output1, targetType, withPacketDependencies: true);
+			});
 		}
 
 		void Convert (string sourceFilePath, string destinationFilePath, AudioFormatType outputFormatType, int? sampleRate = null, AudioConverterOptions? options = null, bool withPacketDependencies = false)

tests/monotouch-test/Foundation/FileManagerTest.cs

@@ -87,8 +87,10 @@ public void GetSkipBackupAttribute ()
 		{
 			Assert.That (NSFileManager.GetSkipBackupAttribute (NSBundle.MainBundle.ExecutableUrl.ToString ()), Is.False, "MainBundle");
 
-			var paths = NSSearchPath.GetDirectories (NSSearchPathDirectory.DocumentDirectory, NSSearchPathDomain.User);
-			var filename = Path.Combine (paths [0], $"DoNotBackupMe-NSFileManager-{Process.GetCurrentProcess ().Id}");
+			// Use the temporary directory instead of the Documents directory: writing to the Documents
+			// directory can trigger a TCC ("Files and Folders") permission prompt on macOS, which hangs
+			// forever in CI (there's no user around to answer the prompt).
+			var filename = Path.Combine (NSFileManager.TemporaryDirectory, $"DoNotBackupMe-NSFileManager-{Process.GetCurrentProcess ().Id}");
 			try {
 				File.WriteAllText (filename, "not worth a bit");
 

tests/monotouch-test/Foundation/UrlTest.cs

@@ -45,8 +45,10 @@ public void IsExcludedFromBackupKey ()
 			Assert.That (value, Is.TypeOf (typeof (NSNumber)), "NSNumber");
 			Assert.That ((int) (value as NSNumber), Is.EqualTo (0), "0");
 
-			var paths = NSSearchPath.GetDirectories (NSSearchPathDirectory.DocumentDirectory, NSSearchPathDomain.User);
-			var filename = Path.Combine (paths [0], $"DoNotBackupMe-NSUrl-{Process.GetCurrentProcess ().Id}");
+			// Use the temporary directory instead of the Documents directory: writing to the Documents
+			// directory can trigger a TCC ("Files and Folders") permission prompt on macOS, which hangs
+			// forever in CI (there's no user around to answer the prompt).
+			var filename = Path.Combine (NSFileManager.TemporaryDirectory, $"DoNotBackupMe-NSUrl-{Process.GetCurrentProcess ().Id}");
 			try {
 				File.WriteAllText (filename, "not worth a bit");
 				using (NSUrl url = NSUrl.FromFilename (filename)) {

tests/xharness/Harness.cs

@@ -195,6 +195,31 @@ bool IsVariableSet (string variable)
 			return result;
 		}
 
+		string? spawnerPath;
+		public string SpawnerPath {
+			get {
+				if (spawnerPath is null)
+					spawnerPath = Path.GetFullPath (Path.Combine (RootDirectory, "..", "tools", "spawner", "spawner"));
+				return spawnerPath;
+			}
+		}
+
+		public void UseSpawner (ProcessStartInfo processStartInfo, IList<string> arguments)
+		{
+			if (!string.IsNullOrEmpty (processStartInfo.Arguments))
+				throw new InvalidOperationException ($"ProcessStartInfo.Arguments must be empty when using UseSpawner.");
+			if (processStartInfo.ArgumentList.Count > 0)
+				throw new InvalidOperationException ($"ProcessStartInfo.ArgumentList must be empty when using UseSpawner.");
+			if (!File.Exists (SpawnerPath))
+				throw new FileNotFoundException ($"The spawner executable was not found. Did you build it? (make -C tools/spawner)", SpawnerPath);
+
+			var originalFileName = processStartInfo.FileName;
+			processStartInfo.FileName = SpawnerPath;
+			processStartInfo.ArgumentList.Add (originalFileName);
+			foreach (var args in arguments)
+				processStartInfo.ArgumentList.Add (args);
+		}
+
 		public List<TestProject> TestProjects { get; } = new ();
 
 		public bool INCLUDE_IOS { get; }
@@ -290,7 +315,8 @@ public bool GetIncludeSystemPermissionTests (TestPlatform platform, bool device)
 			switch (platform) {
 			case TestPlatform.iOS:
 			case TestPlatform.Mac:
-				// On macOS we can't edit the TCC database easily
+			case TestPlatform.MacCatalyst:
+				// On macOS (and Mac Catalyst, which also runs natively, not in a simulator) we can't edit the TCC database easily
 				// (it requires adding the mac has to be using MDM: https://carlashley.com/2018/09/28/tcc-round-up/)
 				// So by default ignore any tests that would pop up permission dialogs in CI.
 				return !InCI;

tests/xharness/Jenkins/TestTasks/MacExecuteTask.cs

@@ -87,8 +87,11 @@ public override async Task RunTestAsync ()
 						proc.StartInfo.EnvironmentVariables ["DISABLE_SYSTEM_PERMISSION_TESTS"] = "1";
 					proc.StartInfo.EnvironmentVariables ["MONO_DEBUG"] = "no-gdb-backtrace";
 					proc.StartInfo.EnvironmentVariables.Remove ("DYLD_FALLBACK_LIBRARY_PATH"); // VSMac might set this, and the test may end up crashing
-					proc.StartInfo.Arguments = StringUtils.FormatArguments (arguments);
-					Jenkins.MainLog.WriteLine ("Executing {0} ({1})", TestName, Mode);
+
+					// Use the spawner to launch the app, to avoid issues with macOS getting confused who's the responsible process
+					Harness.UseSpawner (proc.StartInfo, arguments);
+
+					Jenkins.MainLog.WriteLine ("Executing {0} ({1} - {2})", TestName, Mode, Variation);
 					var log = Logs.Create ($"execute-{Platform}-{Timestamp}.txt", LogType.ExecutionLog.ToString ());
 					ICrashSnapshotReporter? snapshot = null;
 					if (!Jenkins.Harness.DryRun) {

tests/xharness/Jenkins/TestTasks/RunTest.cs

@@ -128,7 +128,7 @@ public async Task ExecuteProcessAsync (ILog log, string filename, List<string> a
 			envManager.SetEnvironmentVariables (proc);
 			foreach (DictionaryEntry de in proc.StartInfo.EnvironmentVariables)
 				log.WriteLine ($"export {de.Key}={de.Value}");
-			mainLog.WriteLine ("Executing {0} ({1})", testTask.TestName, testTask.Mode);
+			mainLog.WriteLine ("Executing {0} ({1} - {2})", testTask.TestName, testTask.Mode, testTask.Variation);
 			if (!dryRun) {
 				testTask.ExecutionResult = TestExecutingResult.Running;
 				var result = await ProcessManager.RunAsync (proc, log, Timeout);

tools/Makefile

@@ -14,4 +14,8 @@ SUBDIRS+=mlaunch
 
 SUBDIRS += dotnet-linker
 
+ifndef NO_XCODE
+SUBDIRS += spawner
+endif
+
 SUBDIRS += assembly-preparer

tools/devops/automation/templates/tests/run-tests.yml

@@ -73,8 +73,9 @@ steps:
 - bash: |
     set -ex
     make -C msbuild Versions.g.cs
+    make -C tools/spawner
   workingDirectory: $(System.DefaultWorkingDirectory)/$(BUILD_REPOSITORY_TITLE)
-  displayName: Generate constants files 
+  displayName: "Generate / compile dependencies"
   timeoutInMinutes: 15
 
 - pwsh: >-
@@ -127,7 +128,7 @@ steps:
   workingDirectory: $(System.DefaultWorkingDirectory)/$(BUILD_REPOSITORY_TITLE)
   displayName: 'Run tests'
   name: runTests # not to be confused with the displayName, this is used to later use the name of the step to access the output variables from an other job
-  timeoutInMinutes: 840
+  timeoutInMinutes: 165
   ${{ if not(parameters.isPR) }}:
     retryCountOnTaskFailure: ${{ parameters.retryCount }}
 

tools/spawner/.gitignore

@@ -0,0 +1,3 @@
+.libs
+spawner
+

tools/spawner/Makefile

@@ -0,0 +1,33 @@
+TOP=../..
+include $(TOP)/Make.config
+include $(TOP)/mk/rules.mk
+
+# The spawner is a host tool: it always runs on the macOS build machine, and is
+# needed regardless of which platforms are enabled. Don't use the generic
+# per-RID rules from mk/rules.mk, because those are only defined for the
+# platforms that are enabled - so when macOS is disabled (which is the case for
+# most of the test jobs in CI) the .libs/osx-*/spawner.o rules don't exist, and
+# the build fails with "No rule to make target '.libs/osx-arm64/spawner.o'".
+# For the same reason we compute the macOS SDK path directly instead of relying
+# on $(macos_SDK).
+
+SPAWNER_ARCHS=arm64 x86_64
+SPAWNER_SDK=$(shell $(XCODE_DEVELOPER_ROOT)/usr/bin/xcodebuild -version -sdk macosx Path 2>/dev/null)
+
+define SpawnerTemplate
+.libs/$(1):
+	$$(Q) mkdir -p $$@
+
+.libs/$(1)/spawner.o: spawner.c | .libs/$(1)
+	$$(Q_CC) $$(CLANG) -arch $(1) -isysroot $$(SPAWNER_SDK) -c $$< -o $$@
+
+.libs/$(1)/spawner: .libs/$(1)/spawner.o
+	$$(Q_CCLD) $$(CLANG) -arch $(1) -isysroot $$(SPAWNER_SDK) $$< -o $$@
+endef
+$(foreach arch,$(SPAWNER_ARCHS),$(eval $(call SpawnerTemplate,$(arch))))
+
+spawner: $(foreach arch,$(SPAWNER_ARCHS),.libs/$(arch)/spawner)
+	$(Q_LIPO) $(LIPO) $^ -create -output $@
+	$(Q) chmod +x $@
+
+all-local:: spawner

tools/spawner/README.md

@@ -0,0 +1,69 @@
+SPAWNER
+=======
+
+This is a very simple tool, which executes another process, disclaiming any
+responsibility for it.
+
+This is important when executing tests apps, because when macOS sees that an
+app uses API that needs specific entries in the Info.plist (such as the
+`NSAppleMusicUsageDescription`), the responsible process is where macOS looks
+for said key.
+
+Example crash report:
+
+```
+Process:               introspection [85822]
+Path:                  /Users/USER/*/introspection.app/Contents/MacOS/introspection
+Identifier:            com.xamarin.introspection
+Version:               1.0 (1.0)
+Code Type:             ARM-64 (Native)
+Parent Process:        dotnet [81129]
+Responsible:           Electron [68966]
+User ID:               501
+
+Date/Time:             2025-11-13 17:33:10.8123 +0100
+OS Version:            macOS 15.7.2 (24G325)
+Report Version:        12
+Anonymous UUID:        F22C0F06-0F16-E475-C0CB-264A0FF4F6A3
+
+
+Time Awake Since Boot: 27000 seconds
+
+System Integrity Protection: enabled
+
+Crashed Thread:        16  Dispatch queue: com.apple.root.default-qos
+
+Exception Type:        EXC_CRASH (SIGKILL)
+Exception Codes:       0x0000000000000000, 0x0000000000000000
+
+Termination Reason:    Namespace TCC, Code 0 
+This app has crashed because it attempted to access privacy-sensitive data without a usage description. The app's Info.plist must contain an NSAppleMusicUsageDescription key with a string value explaining to the user how the app uses this data.
+```
+
+The app crashed because macOS says it needs the `NSAppleMusicUsageDescription` entry in its `Info.plist` file.
+
+This is confusing, because introspection _has_ an `NSAppleMusicUsageDescription` entry in its `Info.plist` file.
+
+Here's what happens:
+
+Note that there's a "Responsible [Process]" (Electron 68966) line, which is not the same as "Process" (introspection 85822), and this is the crux of the matter.
+
+In this particular case:
+
+* I opened the xharness project in VSCode.
+* I launched the xharness project in the debugger, and then ran introspection for Mac Catalyst.
+* The responsible process ended up being VS Code (aka Electron, with pid 68966), and that's where macOS ended up looking for the `NSAppleMusicUsageDescription` key.
+
+The fix is to launch `introspection` (and any other test app on macOS) using
+this `spawner` tool, which disclaims responsibility for anything it launches,
+thus letting `introspection` be a grown up process and fully responsible for
+itself.
+
+Usage is simple: just pass the executable + any arguments to `spawner`.
+
+References:
+
+* https://gitlab.com/gnachman/iterm2/-/issues/10360
+* https://github.com/llvm/llvm-project/commit/041c7b84a4b925476d1e21ed302786033bb6035f#diff-a38ae411ccf0c85f3d7c0c45d8e1ad035030d5171d59e478b86a094941d3209dR16-R17
+* https://lldb.llvm.org/cpp_reference/PosixSpawnResponsible_8h_source.html
+* https://steipete.me/posts/2025/applescript-cli-macos-complete-guide

tools/spawner/spawner.c

@@ -0,0 +1,72 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+#include <errno.h>
+#include <signal.h>
+#include <spawn.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <string.h>
+
+errno_t responsibility_spawnattrs_setdisclaim (posix_spawnattr_t *attrs, bool disclaim);
+
+int main (int argc, char** argv, char** envp)
+{
+	if (argc < 2) {
+		fprintf (stderr,
+			"spawner: launch a subprocess, disclaiming all responsibilities with regards to TCC:\n"
+			"usage: spawner <command> [arguments]\n");
+		return 1;
+	}
+
+	int rv;
+	// Behave as exec
+	short flags = POSIX_SPAWN_SETEXEC;
+	posix_spawnattr_t spawnattr;
+	sigset_t sigset;
+
+	rv = posix_spawnattr_init (&spawnattr);
+	if (rv) {
+		fprintf (stderr, "Failed to execute 'posix_spawnattr_init': %i (%s)\n", rv, strerror (rv));
+		return 1;
+	}
+
+	// Reset the signal mask
+	sigemptyset (&sigset);
+	rv = posix_spawnattr_setsigmask (&spawnattr, &sigset);
+	if (rv) {
+		fprintf (stderr, "Failed to execute 'posix_spawnattr_setsigmask': %i (%s)\n", rv, strerror (rv));
+		return 1;
+	}
+	flags |= POSIX_SPAWN_SETSIGMASK;
+
+	// Reset all signals to their default handlers
+	sigfillset (&sigset);
+	rv = posix_spawnattr_setsigdefault (&spawnattr, &sigset);
+	if (rv) {
+		fprintf (stderr, "Failed to execute 'posix_spawnattr_setsigdefault': %i (%s)\n", rv, strerror (rv));
+		return 1;
+	}
+	flags |= POSIX_SPAWN_SETSIGDEF;
+
+	rv = posix_spawnattr_setflags (&spawnattr, flags);
+	if (rv) {
+		fprintf (stderr, "Failed to execute 'posix_spawnattr_setflags': %i (%s)\n", rv, strerror (rv));
+		return 1;
+	}
+
+	rv = responsibility_spawnattrs_setdisclaim (&spawnattr, 1);
+	if (rv) {
+		fprintf (stderr, "Failed to execute 'responsibility_spawnattrs_setdisclaim': %i (%s)\n", rv, strerror (rv));
+		return 1;
+	}
+
+	pid_t pid = 0;
+	rv = posix_spawnp (&pid, argv [1], NULL, &spawnattr, argv + 1, envp);
+	posix_spawnattr_destroy (&spawnattr);
+
+	// posix_spawnp shouldn't return (because we set the POSIX_SPAWN_SETEXEC flag)
+	// so if it did, something went wrong
+	fprintf (stderr, "Failed to execute '%s': %i (%s)\n", argv [1], rv, strerror (rv));
+	return 1;
+}