Implement auto-restarting on rude edit or no-effect change

Author: tmat

sdk.sln

@@ -100,7 +100,7 @@ public override async Task WatchAsync(CancellationToken shutdownCancellationToke
                     }
 
                     var projectMap = new ProjectNodeMap(evaluationResult.ProjectGraph, Context.Reporter);
-                    compilationHandler = new CompilationHandler(Context.Reporter, Context.EnvironmentOptions, shutdownCancellationToken);
+                    compilationHandler = new CompilationHandler(Context.Reporter, Context.EnvironmentOptions, Context.Options, shutdownCancellationToken);
                     var scopedCssFileHandler = new ScopedCssFileHandler(Context.Reporter, projectMap, browserConnector);
                     var projectLauncher = new ProjectLauncher(Context, projectMap, browserConnector, compilationHandler, iteration);
                     var outputDirectories = GetProjectOutputDirectories(evaluationResult.ProjectGraph);

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

@@ -45,6 +45,9 @@ public static string GetAssemblyName(this ProjectGraphNode projectNode)
     public static IEnumerable<string> GetCapabilities(this ProjectGraphNode projectNode)
         => projectNode.ProjectInstance.GetItems("ProjectCapability").Select(item => item.EvaluatedInclude);
 
+    public static bool IsAutoRestartEnabled(this ProjectGraphNode projectNode)
+        => bool.TryParse(projectNode.ProjectInstance.GetPropertyValue("HotReloadAutoRestart"), out var result) && result;
+
     public static IEnumerable<ProjectGraphNode> GetTransitivelyReferencingProjects(this IEnumerable<ProjectGraphNode> projects)
     {
         var visited = new HashSet<ProjectGraphNode>();

src/BuiltInTools/dotnet-watch/HotReloadDotNetWatcher.cs

@@ -30,4 +30,4 @@
     await Task.Delay(1000);
 }
 
-class C { }
+class C { /* member placeholder */ }

src/BuiltInTools/dotnet-watch/Utilities/ProjectGraphNodeExtensions.cs

@@ -67,6 +67,83 @@ public static void Print()
             await App.AssertOutputLineStartsWith("Changed!");
         }
 
+        [Theory]
+        [CombinatorialData]
+        public async Task AutoRestartOnRudeEdit(bool nonInteractive)
+        {
+            var testAsset = TestAssets.CopyTestAsset("WatchHotReloadApp")
+                .WithSource();
+
+            if (!nonInteractive)
+            {
+                testAsset = testAsset
+                    .WithProjectChanges(project =>
+                    {
+                        project.Root.Descendants()
+                            .First(e => e.Name.LocalName == "PropertyGroup")
+                            .Add(XElement.Parse("""
+                                <HotReloadAutoRestart>true</HotReloadAutoRestart>
+                                """));
+                    });
+            }
+
+            var programPath = Path.Combine(testAsset.Path, "Program.cs");
+
+            App.Start(testAsset, nonInteractive ? ["--non-interactive"] : []);
+
+            await App.AssertWaitingForChanges();
+            App.Process.ClearOutput();
+
+            // rude edit: adding virtual method
+            UpdateSourceFile(programPath, src => src.Replace("/* member placeholder */", "public virtual void F() {}"));
+
+            await App.AssertOutputLineStartsWith(MessageDescriptor.WaitingForChanges, failure: _ => false);
+
+            App.AssertOutputContains("⌚ Restart is needed to apply the changes");
+            App.AssertOutputContains($"❌ [auto-restart] {programPath}(33,11): error ENC0023: Adding an abstract method or overriding an inherited method requires restarting the application.");
+            App.AssertOutputContains($"[WatchHotReloadApp ({ToolsetInfo.CurrentTargetFramework})] Exited");
+            App.AssertOutputContains($"[WatchHotReloadApp ({ToolsetInfo.CurrentTargetFramework})] Launched");
+        }
+
+        [Theory]
+        [CombinatorialData]
+        public async Task AutoRestartOnNoEffectEdit(bool nonInteractive)
+        {
+            var testAsset = TestAssets.CopyTestAsset("WatchHotReloadApp")
+                .WithSource();
+
+            if (!nonInteractive)
+            {
+                testAsset = testAsset
+                    .WithProjectChanges(project =>
+                    {
+                        project.Root.Descendants()
+                            .First(e => e.Name.LocalName == "PropertyGroup")
+                            .Add(XElement.Parse("""
+                            <HotReloadAutoRestart>true</HotReloadAutoRestart>
+                            """));
+                    });
+            }
+
+            var programPath = Path.Combine(testAsset.Path, "Program.cs");
+
+            App.Start(testAsset, nonInteractive ? ["--non-interactive"] : []);
+
+            await App.AssertWaitingForChanges();
+            App.Process.ClearOutput();
+
+            // rude edit: adding virtual method
+            UpdateSourceFile(programPath, src => src.Replace("Started", "<Updated>"));
+
+            await App.AssertOutputLineStartsWith(MessageDescriptor.WaitingForChanges, failure: _ => false);
+
+            App.AssertOutputContains("⌚ Restart is needed to apply the changes");
+            App.AssertOutputContains($"⚠ [auto-restart] {programPath}(16,19): warning ENC0118: Changing 'top-level code' might not have any effect until the application is restarted.");
+            App.AssertOutputContains($"[WatchHotReloadApp ({ToolsetInfo.CurrentTargetFramework})] Exited");
+            App.AssertOutputContains($"[WatchHotReloadApp ({ToolsetInfo.CurrentTargetFramework})] Launched");
+            App.AssertOutputContains("<Updated>");
+        }
+
         /// <summary>
         /// Unchanged project doesn't build. Wait for source change and rebuild.
         /// </summary>
@@ -682,7 +759,7 @@ public async Task Aspire()
 
             await App.AssertOutputLineStartsWith("  ❔ Do you want to restart these projects? Yes (y) / No (n) / Always (a) / Never (v)");
 
-            App.AssertOutputContains("dotnet watch ⌚ Unable to apply hot reload, restart is needed to apply the changes.");
+            App.AssertOutputContains("dotnet watch ⌚ Restart is needed to apply the changes.");
             App.AssertOutputContains("error ENC0020: Renaming record 'WeatherForecast' requires restarting the application.");
             App.AssertOutputContains("dotnet watch ⌚ Affected projects:");
             App.AssertOutputContains("dotnet watch ⌚   WatchAspire.ApiService");

test/TestAssets/TestProjects/WatchHotReloadApp/Program.cs

@@ -27,7 +27,7 @@ public async Task ReferenceOutputAssembly_False()
             reporter);
 
         var projectGraph = factory.TryLoadProjectGraph(projectGraphRequired: false);
-        var handler = new CompilationHandler(reporter, environmentOptions, CancellationToken.None);
+        var handler = new CompilationHandler(reporter, environmentOptions, new GlobalOptions(), CancellationToken.None);
 
         await handler.Workspace.UpdateProjectConeAsync(hostProject, CancellationToken.None);
 

test/dotnet-watch.Tests/HotReload/ApplyDeltaTests.cs

@@ -526,7 +526,6 @@ public async Task RudeEditInProjectWithoutRunningProcess()
         Log("Waiting for change handled ...");
         await changeHandled.WaitAsync(w.ShutdownSource.Token);
 
-        w.Reporter.ProcessOutput.Contains("verbose ⌚ Rude edits detected but do not affect any running process");
         w.Reporter.ProcessOutput.Contains($"verbose ❌ {serviceSourceA2}(1,12): error ENC0003: Updating 'attribute' requires restarting the application.");
     }