Cleanup

src/BuiltInTools/dotnet-watch/Aspire/AspireServiceFactory.cs

@@ -89,15 +89,6 @@ public async ValueTask TerminateLaunchedProcessesAsync(CancellationToken cancell
             }
         }
 
-        /// <summary>
-        /// When shutting down we terminate all processes created by Aspire service first.
-        /// Then we terminate the AppHost (root project) without terminating the entire process tree,
-        /// so that we don't kill DCP before it has a chance to clean up resources.
-        /// </summary>
-        public bool TerminateEntireProcessTreeOnShutdown
-            // This does not work on OSX/Linux. /~https://github.com/dotnet/sdk/issues/44496
-            => false;   //!RuntimeInformation.IsOSPlatform(OSPlatform.Windows);
-
         public IEnumerable<(string name, string value)> GetEnvironmentVariables()
             => _service.GetServerConnectionEnvironment().Select(kvp => (kvp.Key, kvp.Value));
 
@@ -255,7 +246,6 @@ private ProjectOptions GetProjectOptions(ProjectLaunchRequest projectLaunchInfo)
                 LaunchProfileName = projectLaunchInfo.LaunchProfile,
                 NoLaunchProfile = projectLaunchInfo.DisableLaunchProfile,
                 TargetFramework = null, // TODO: Should DCP protocol specify?
-                TerminateEntireProcessTreeOnShutdown = TerminateEntireProcessTreeOnShutdown,
             };
         }
     }

src/BuiltInTools/dotnet-watch/CommandLineOptions.cs

@@ -281,6 +281,5 @@ public ProjectOptions GetProjectOptions(string projectPath, string workingDirect
             LaunchProfileName = LaunchProfileName,
             NoLaunchProfile = NoLaunchProfile,
             TargetFramework = TargetFramework,
-            TerminateEntireProcessTreeOnShutdown = true,
         };
 }

src/BuiltInTools/dotnet-watch/DotNetWatcher.cs

@@ -61,8 +61,7 @@ public override async Task WatchAsync(CancellationToken shutdownCancellationToke
                     {
                         [EnvironmentVariables.Names.DotnetWatch] = "1",
                         [EnvironmentVariables.Names.DotnetWatchIteration] = (iteration + 1).ToString(CultureInfo.InvariantCulture),
-                    },
-                    TerminateEntireProcessTree = true,
+                    }
                 };
 
                 var browserRefreshServer = (projectRootNode != null)

src/BuiltInTools/dotnet-watch/HotReload/CompilationHandler.cs

@@ -109,7 +109,7 @@ private DeltaApplier CreateDeltaApplier(ProjectGraphNode projectNode, BrowserRef
                 _ => new DefaultDeltaApplier(processReporter),
             };
 
-        public async Task<RunningProject> TrackRunningProjectAsync(
+        public async Task<RunningProject?> TrackRunningProjectAsync(
             ProjectGraphNode projectNode,
             ProjectOptions projectOptions,
             string namedPipeName,
@@ -132,18 +132,20 @@ public async Task<RunningProject> TrackRunningProjectAsync(
             // It is important to first create the named pipe connection (delta applier is the server)
             // and then start the process (named pipe client). Otherwise, the connection would fail.
             deltaApplier.CreateConnection(namedPipeName, processCommunicationCancellationSource.Token);
-            var launchResult = new ProcessLaunchResult();
 
             processSpec.OnExit += (_, _) =>
             {
                 processExitedSource.Cancel();
                 return ValueTask.CompletedTask;
             };
 
+            var launchResult = new ProcessLaunchResult();
             var runningProcess = ProcessRunner.RunAsync(processSpec, processReporter, isUserApplication: true, launchResult, processTerminationSource.Token);
-
-            // RunAsync throws if process can't be launched, otherwise we must have a PID.
-            Debug.Assert(launchResult.ProcessId != null);
+            if (launchResult.ProcessId == null)
+            {
+                // error already reported
+                return null;
+            }
 
             var capabilityProvider = deltaApplier.GetApplyUpdateCapabilitiesAsync(processCommunicationCancellationSource.Token);
             var runningProject = new RunningProject(

src/BuiltInTools/dotnet-watch/HotReload/IRuntimeProcessLauncher.cs

@@ -11,11 +11,6 @@ internal interface IRuntimeProcessLauncher : IAsyncDisposable
 {
     IEnumerable<(string name, string value)> GetEnvironmentVariables();
 
-    /// <summary>
-    /// True if shutting down the root process should terminate its entire process tree.
-    /// </summary>
-    bool TerminateEntireProcessTreeOnShutdown { get; }
-
     /// <summary>
     /// Initiates shutdown. Terminates all created processes.
     /// </summary>

src/BuiltInTools/dotnet-watch/HotReload/ProjectLauncher.cs

@@ -47,24 +47,11 @@ public EnvironmentOptions EnvironmentOptions
             return null;
         }
 
-        return await LaunchProcessAsync(projectOptions, projectNode, processTerminationSource, onOutput, restartOperation, build, cancellationToken);
-    }
-
-    public async ValueTask<RunningProject> LaunchProcessAsync(
-        ProjectOptions projectOptions,
-        ProjectGraphNode projectNode,
-        CancellationTokenSource processTerminationSource,
-        Action<OutputLine>? onOutput,
-        RestartOperation restartOperation,
-        bool build,
-        CancellationToken cancellationToken)
-    {
         var processSpec = new ProcessSpec
         {
             Executable = EnvironmentOptions.MuxerPath,
             WorkingDirectory = projectOptions.WorkingDirectory,
             OnOutput = onOutput,
-            TerminateEntireProcessTree = projectOptions.TerminateEntireProcessTreeOnShutdown,
             Arguments = build || projectOptions.Command is not ("run" or "test")
                 ? [projectOptions.Command, .. projectOptions.CommandArguments]
                 : [projectOptions.Command, "--no-build", .. projectOptions.CommandArguments]

src/BuiltInTools/dotnet-watch/HotReloadDotNetWatcher.cs

@@ -112,8 +112,7 @@ public override async Task WatchAsync(CancellationToken shutdownCancellationToke
                         var launcherEnvironment = runtimeProcessLauncher.GetEnvironmentVariables();
                         rootProjectOptions = rootProjectOptions with
                         {
-                            LaunchEnvironmentVariables = [.. rootProjectOptions.LaunchEnvironmentVariables, .. launcherEnvironment],
-                            TerminateEntireProcessTreeOnShutdown = runtimeProcessLauncher.TerminateEntireProcessTreeOnShutdown
+                            LaunchEnvironmentVariables = [.. rootProjectOptions.LaunchEnvironmentVariables, .. launcherEnvironment]
                         };
                     }
 

src/BuiltInTools/dotnet-watch/Internal/IReporter.cs

@@ -60,7 +60,6 @@ public bool TryGetMessage(string? prefix, object?[] args, [NotNullWhen(true)] ou
         public static readonly MessageDescriptor WaitingForChanges = new("Waiting for changes", "⌚", MessageSeverity.Verbose, s_id++);
         public static readonly MessageDescriptor LaunchedProcess = new("Launched '{0}' with arguments '{1}': process id {2}", "🚀", MessageSeverity.Verbose, s_id++);
         public static readonly MessageDescriptor KillingProcess = new("Killing process {0}", "⌚", MessageSeverity.Verbose, s_id++);
-        public static readonly MessageDescriptor KillingProcessTree = new("Killing entire process tree of process {0}", "⌚", MessageSeverity.Verbose, s_id++);
         public static readonly MessageDescriptor HotReloadChangeHandled = new("Hot reload change handled in {0}ms.", "🔥", MessageSeverity.Verbose, s_id++);
         public static readonly MessageDescriptor HotReloadSucceeded = new("Hot reload succeeded.", "🔥", MessageSeverity.Output, s_id++);
         public static readonly MessageDescriptor BuildCompleted = new("Build completed.", "⌚", MessageSeverity.Verbose, s_id++);

src/BuiltInTools/dotnet-watch/Internal/MsBuildFileSetFactory.cs

@@ -51,8 +51,7 @@ internal class MSBuildFileSetFactory(
                         {
                             capturedOutput.Add(line);
                         }
-                    },
-                    TerminateEntireProcessTree = true,
+                    }
                 };
 
                 reporter.Verbose($"Running MSBuild target '{TargetName}' on '{rootProjectFile}'");