Traversal2

src/BuiltInTools/Watch/Browser/BrowserLauncher.cs

@@ -3,10 +3,9 @@
 
 using System.Collections.Immutable;
 using System.Diagnostics;
-using System.Diagnostics.CodeAnalysis;
-using System.Runtime.CompilerServices;
 using Microsoft.Build.Graph;
 using Microsoft.DotNet.HotReload;
+using Microsoft.DotNet.ProjectTools;
 using Microsoft.Extensions.Logging;
 
 namespace Microsoft.DotNet.Watch;
@@ -26,7 +25,7 @@ public void InstallBrowserLaunchTrigger(
         AbstractBrowserRefreshServer? server,
         CancellationToken cancellationToken)
     {
-        if (!CanLaunchBrowser(projectOptions, out var launchProfile))
+        if (!CanLaunchBrowser(projectOptions, out var profileLaunchUrl))
         {
             if (environmentOptions.TestFlags.HasFlag(TestFlags.MockBrowser))
             {
@@ -42,7 +41,7 @@ public void InstallBrowserLaunchTrigger(
                 ImmutableInterlocked.Update(ref _browserLaunchAttempted, static (set, key) => set.Add(key), projectNode.GetProjectInstanceId()))
             {
                 // first build iteration of a root project:
-                var launchUrl = GetLaunchUrl(launchProfile.LaunchUrl, url);
+                var launchUrl = GetLaunchUrl(profileLaunchUrl, url);
                 LaunchBrowser(launchUrl, server);
             }
             else if (server != null)
@@ -99,9 +98,9 @@ private void LaunchBrowser(string launchUrl, AbstractBrowserRefreshServer? serve
         }
     }
 
-    private bool CanLaunchBrowser(ProjectOptions projectOptions, [NotNullWhen(true)] out LaunchSettingsProfile? launchProfile)
+    private bool CanLaunchBrowser(ProjectOptions projectOptions, out string? launchUrl)
     {
-        launchProfile = null;
+        launchUrl = null;
 
         if (environmentOptions.SuppressLaunchBrowser)
         {
@@ -114,20 +113,16 @@ private bool CanLaunchBrowser(ProjectOptions projectOptions, [NotNullWhen(true)]
             return false;
         }
 
-        launchProfile = GetLaunchProfile(projectOptions);
-        if (launchProfile is not { LaunchBrowser: true })
+        var launchProfile = projectOptions.GetLaunchProfile(logger);
+        if (launchProfile is not ProjectLaunchProfile { LaunchBrowser: true, LaunchUrl: var url})
         {
             logger.LogDebug("launchSettings does not allow launching browsers.");
             return false;
         }
 
         logger.Log(MessageDescriptor.ConfiguredToLaunchBrowser);
-        return true;
-    }
 
-    private LaunchSettingsProfile GetLaunchProfile(ProjectOptions projectOptions)
-    {
-        return (projectOptions.NoLaunchProfile == true
-            ? null : LaunchSettingsProfile.ReadLaunchProfile(projectOptions.ProjectPath, projectOptions.LaunchProfileName, logger)) ?? new();
+        launchUrl = url;
+        return true;
     }
 }

src/BuiltInTools/Watch/Build/BuildNames.cs

@@ -45,6 +45,7 @@ internal static class TargetNames
 {
     public const string Compile = nameof(Compile);
     public const string Restore = nameof(Restore);
+    public const string CompileDesignTime = nameof(CompileDesignTime);
     public const string GenerateComputedBuildStaticWebAssets = nameof(GenerateComputedBuildStaticWebAssets);
     public const string ReferenceCopyLocalPathsOutputGroup = nameof(ReferenceCopyLocalPathsOutputGroup);
 }
@@ -54,4 +55,5 @@ internal static class ProjectCapability
     public const string Aspire = nameof(Aspire);
     public const string AspNetCore = nameof(AspNetCore);
     public const string WebAssembly = nameof(WebAssembly);
+    public const string SupportsHotReload = nameof(SupportsHotReload);
 }

src/BuiltInTools/Watch/Build/EvaluationResult.cs

@@ -95,8 +95,13 @@ public static ImmutableDictionary<string, string> GetGlobalBuildOptions(IEnumera
             // populated by design-time build.
             var projectInstance = project.ProjectInstance.DeepCopy();
 
-            // skip outer build project nodes:
-            if (projectInstance.GetPropertyValue(PropertyNames.TargetFramework) == "")
+            var compileTarget = projectInstance.Targets.ContainsKey(TargetNames.CompileDesignTime)
+                ? TargetNames.CompileDesignTime
+                : projectInstance.Targets.ContainsKey(TargetNames.Compile)
+                ? TargetNames.Compile
+                : null;
+
+            if (compileTarget == null)
             {
                 continue;
             }
@@ -105,7 +110,7 @@ public static ImmutableDictionary<string, string> GetGlobalBuildOptions(IEnumera
 
             using (var loggers = buildReporter.GetLoggers(projectInstance.FullPath, "DesignTimeBuild"))
             {
-                if (!projectInstance.Build([TargetNames.Compile, .. customCollectWatchItems], loggers))
+                if (!projectInstance.Build([compileTarget, .. customCollectWatchItems], loggers))
                 {
                     logger.LogError("Failed to build project '{Path}'.", projectInstance.FullPath);
                     loggers.ReportOutput();
@@ -116,7 +121,6 @@ public static ImmutableDictionary<string, string> GetGlobalBuildOptions(IEnumera
             var projectPath = projectInstance.FullPath;
             var projectDirectory = Path.GetDirectoryName(projectPath)!;
 
-            // TODO: Compile and AdditionalItems should be provided by Roslyn
             var items = projectInstance.GetItems(ItemNames.Compile)
                 .Concat(projectInstance.GetItems(ItemNames.AdditionalFiles))
                 .Concat(projectInstance.GetItems(ItemNames.Watch));

src/BuiltInTools/Watch/Context/ProjectOptions.cs

@@ -1,10 +1,16 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
+using System.Runtime.CompilerServices;
+using Microsoft.DotNet.ProjectTools;
+using Microsoft.Extensions.Logging;
+
 namespace Microsoft.DotNet.Watch;
 
 internal sealed record ProjectOptions
 {
+    private StrongBox<LaunchProfile?>? _lazyLaunchProfile;
+
     public required bool IsRootProject { get; init; }
     public required string ProjectPath { get; init; }
     public required string WorkingDirectory { get; init; }
@@ -33,4 +39,42 @@ internal sealed record ProjectOptions
     /// </summary>
     public bool IsCodeExecutionCommand
         => Command is "run" or "test";
+
+    public LaunchProfile? GetLaunchProfile(ILogger logger)
+    {
+        return (_lazyLaunchProfile ??= new StrongBox<LaunchProfile?>(ReadProfile())).Value;
+
+        LaunchProfile? ReadProfile()
+        {
+            if (NoLaunchProfile)
+            {
+                return null;
+            }
+
+            var launchSettingsPath = LaunchSettings.TryFindLaunchSettingsFile(ProjectPath, LaunchProfileName, (message, isError) =>
+            {
+                if (isError)
+                {
+                    logger.LogError(message);
+                }
+                else
+                {
+                    logger.LogWarning(message);
+                }
+            });
+
+            if (launchSettingsPath == null)
+            {
+                return null;
+            }
+
+            var result = LaunchSettings.ReadProfileSettingsFromFile(launchSettingsPath, LaunchProfileName);
+            if (result.FailureReason != null)
+            {
+                logger.LogError("Failed to read launch settings from '{LaunchSettingsPath}': {FailureReason}", launchSettingsPath, result.FailureReason);
+            }
+
+            return result.Profile;
+        }
+    }
 }

src/BuiltInTools/Watch/HotReload/HotReloadDotNetWatcher.cs

@@ -6,6 +6,7 @@
 using Microsoft.Build.Graph;
 using Microsoft.CodeAnalysis;
 using Microsoft.DotNet.HotReload;
+using Microsoft.DotNet.ProjectTools;
 using Microsoft.Extensions.Logging;
 
 namespace Microsoft.DotNet.Watch
@@ -246,7 +247,8 @@ void FileChangedCallback(ChangedPath change)
                             continue;
                         }
 
-                        if (!rootProjectCapabilities.Contains("SupportsHotReload"))
+                        if (rootProjectOptions.GetLaunchProfile(_context.Logger) is not ExecutableLaunchProfile &&
+                            !rootProjectCapabilities.Contains(ProjectCapability.SupportsHotReload))
                         {
                             _context.Logger.LogWarning("Project '{Name}' does not support Hot Reload and must be rebuilt.", rootProject.GetDisplayName());
 

src/BuiltInTools/Watch/Process/ProjectLauncher.cs

@@ -3,6 +3,7 @@
 
 using System.Globalization;
 using Microsoft.DotNet.HotReload;
+using Microsoft.DotNet.ProjectTools;
 using Microsoft.Extensions.Logging;
 
 namespace Microsoft.DotNet.Watch;
@@ -41,7 +42,12 @@ public EnvironmentOptions EnvironmentOptions
             return null;
         }
 
-        if (!projectNode.IsNetCoreApp(Versions.Version6_0))
+        var launchProfile = projectOptions.GetLaunchProfile(context.Logger);
+
+        // TODO: extract TFM from Exe
+        // If an executable profile is being used to launch the application the TFM of the project is irrelevant.
+        if (launchProfile is not ExecutableLaunchProfile &&
+            !projectNode.IsNetCoreApp(Versions.Version6_0))
         {
             Logger.LogError($"Hot Reload based watching is only supported in .NET 6.0 or newer apps. Use --no-hot-reload switch or update the project's launchSettings.json to disable this feature.");
             return null;

src/BuiltInTools/dotnet-watch/Properties/launchSettings.json

@@ -3,7 +3,7 @@
     "dotnet-watch": {
       "commandName": "Project",
       "commandLineArgs": "--verbose -bl",
-      "workingDirectory": "C:\\bugs\\9756\\aspire-watch-start-issue\\Aspire.AppHost",
+      "workingDirectory": "C:\\Temp\\Traversal",
       "environmentVariables": {
         "DOTNET_WATCH_DEBUG_SDK_DIRECTORY": "$(RepoRoot)artifacts\\bin\\redist\\$(Configuration)\\dotnet\\sdk\\$(Version)",
         "DCP_IDE_REQUEST_TIMEOUT_SECONDS": "100000",
@@ -13,4 +13,4 @@
       }
     }
   }
-}
+}