Fix NativeAOT tracing tests using AppContext.BaseDirectory and Environment.ProcessPath

src/tests/tracing/userevents/activity/activity.cs

@@ -151,7 +151,6 @@ public static int Main(string[] args)
             return UserEventsTestRunner.Run(
                 args,
                 "activity",
-                typeof(Activity).Assembly.Location,
                 ActivityTracee,
                 s_traceValidator);
         }

src/tests/tracing/userevents/basic/basic.cs

@@ -55,7 +55,6 @@ public static int Main(string[] args)
             return UserEventsTestRunner.Run(
                 args,
                 "basic",
-                typeof(Basic).Assembly.Location,
                 BasicTracee,
                 s_traceValidator);
         }

src/tests/tracing/userevents/common/UserEventsTestRunner.cs

@@ -26,7 +26,6 @@ public class UserEventsTestRunner
         public static int Run(
             string[] args,
             string scenarioName,
-            string traceeAssemblyPath,
             Action traceeAction,
             Func<EventPipeEventSource, bool> traceValidator,
             int traceeExitTimeout = DefaultTraceeExitTimeoutMs,
@@ -46,20 +45,21 @@ public static int Run(
 
             return RunOrchestrator(
                 scenarioName,
-                traceeAssemblyPath,
                 traceValidator,
                 traceeExitTimeout,
                 recordTraceExitTimeout);
         }
 
         private static int RunOrchestrator(
             string scenarioName,
-            string traceeAssemblyPath,
             Func<EventPipeEventSource, bool> traceValidator,
             int traceeExitTimeout,
             int recordTraceExitTimeout)
         {
-            string userEventsScenarioDir = Path.GetDirectoryName(traceeAssemblyPath);
+            // Use AppContext.BaseDirectory which works consistently for both CoreCLR and NativeAOT.
+            // For CoreCLR: .../tracing/userevents/<scenario>/<scenario>/
+            // For NativeAOT: .../tracing/userevents/<scenario>/<scenario>/ (even though exe is in native/ subdirectory)
+            string userEventsScenarioDir = AppContext.BaseDirectory;
             string recordTracePath = ResolveRecordTracePath(userEventsScenarioDir);
             string scriptFilePath = Path.Combine(userEventsScenarioDir, $"{scenarioName}.script");
 
@@ -115,8 +115,8 @@ private static int RunOrchestrator(
             Console.WriteLine($"record-trace started with PID: {recordTraceProcess.Id}");
 
             ProcessStartInfo traceeStartInfo = new();
-            traceeStartInfo.FileName = Process.GetCurrentProcess().MainModule!.FileName;
-            traceeStartInfo.Arguments = $"{traceeAssemblyPath} tracee";
+            traceeStartInfo.FileName = Environment.ProcessPath!;
+            traceeStartInfo.Arguments = "tracee";
             traceeStartInfo.WorkingDirectory = userEventsScenarioDir;
             traceeStartInfo.RedirectStandardOutput = true;
             traceeStartInfo.RedirectStandardError = true;
@@ -125,6 +125,10 @@ private static int RunOrchestrator(
             string diagnosticPortDir = "/tmp";
             traceeStartInfo.Environment["TMPDIR"] = diagnosticPortDir;
 
+            // Note: record-trace uses perfmap/doublemapper to discover .NET process PIDs and their diagnostic ports.
+            // NativeAOT apps do not use doublemapping, so they will not be discovered by record-trace even with TMPDIR set.
+            // See https://github.com/microsoft/one-collect/issues/226 for details.
+
             // TMPDIR is configured on Helix, but the diagnostic port is created outside of Helix's default temp datadisk path.
             // The diagnostic port should be automatically cleaned up when the tracee shuts down, but zombie sockets can be left
             // behind after catastrophic exits. Clean them before launching the tracee to avoid deleting sockets from a reused PID.
@@ -198,9 +202,10 @@ private static int RunOrchestrator(
 
         private static string ResolveRecordTracePath(string userEventsScenarioDir)
         {
-            // scenario dir: .../tracing/userevents/<scenario>/<scenario>
+            // userEventsScenarioDir is AppContext.BaseDirectory, which points to:
+            // .../tracing/userevents/<scenario>/<scenario>/
+            // Navigate up two directories to reach userevents root, then into common/userevents_common
             string usereventsRoot = Path.GetFullPath(Path.Combine(userEventsScenarioDir, "..", ".."));
-            // common dir: .../tracing/userevents/common/userevents_common
             string commonDir = Path.Combine(usereventsRoot, "common", "userevents_common");
             string recordTracePath = Path.Combine(commonDir, "record-trace");
             return recordTracePath;

src/tests/tracing/userevents/custommetadata/custommetadata.cs

@@ -70,7 +70,6 @@ public static int Main(string[] args)
             return UserEventsTestRunner.Run(
                 args,
                 "custommetadata",
-                typeof(CustomMetadata).Assembly.Location,
                 CustomMetadataTracee,
                 s_traceValidator);
         }

src/tests/tracing/userevents/managedevent/managedevent.cs

@@ -58,7 +58,6 @@ public static int Main(string[] args)
             return UserEventsTestRunner.Run(
                 args,
                 "managedevent",
-                typeof(ManagedEvent).Assembly.Location,
                 ManagedEventTracee,
                 s_traceValidator);
         }

src/tests/tracing/userevents/multithread/multithread.cs

@@ -97,7 +97,6 @@ public static int Main(string[] args)
             return UserEventsTestRunner.Run(
                 args,
                 "multithread",
-                typeof(MultiThread).Assembly.Location,
                 MultiThreadTracee,
                 s_traceValidator);
         }