Remove MSBuild hacks for virtual project building (#49745)

Co-authored-by: Copilot <[email protected]>

Author: jjonescz

src/Cli/dotnet/Commands/Run/VirtualProjectBuildingCommand.cs

@@ -90,70 +90,28 @@ internal sealed class VirtualProjectBuildingCommand : CommandBase
     /// </remarks>
     private static readonly IEnumerable<string> s_ignorableProperties =
     [
-        // This is set by default by `dotnet run`, so it must be ignored otherwise the CSC optimization would not kick in by default.
+        // These are set by default by `dotnet run`, so at least these must be ignored otherwise the CSC optimization would not kick in by default.
         "NuGetInteractive",
+        "_BuildNonexistentProjectsByDefault",
+        "RestoreUseSkipNonexistentTargets",
     ];
 
     public static string TargetFrameworkVersion => Product.TargetFrameworkVersion;
 
-    internal static readonly string TargetOverrides = """
-          <!--
-            Override targets which don't work with project files that are not present on disk.
-            See https://github.com/NuGet/Home/issues/14148.
-          -->
-
-          <Target Name="_FilterRestoreGraphProjectInputItems"
-                  DependsOnTargets="_LoadRestoreGraphEntryPoints">
-            <!-- No-op, the original output is not needed by the overwritten targets. -->
-          </Target>
-
-          <Target Name="_GetAllRestoreProjectPathItems"
-                  DependsOnTargets="_FilterRestoreGraphProjectInputItems;_GenerateRestoreProjectPathWalk"
-                  Returns="@(_RestoreProjectPathItems)">
-            <!-- Output from dependency _GenerateRestoreProjectPathWalk. -->
-          </Target>
-
-          <Target Name="_GenerateRestoreGraph"
-                  DependsOnTargets="_FilterRestoreGraphProjectInputItems;_GetAllRestoreProjectPathItems;_GenerateRestoreGraphProjectEntry;_GenerateProjectRestoreGraph"
-                  Returns="@(_RestoreGraphEntry)">
-            <!-- Output partly from dependency _GenerateRestoreGraphProjectEntry and _GenerateProjectRestoreGraph. -->
-
-            <ItemGroup>
-              <_GenerateRestoreGraphProjectEntryInput Include="@(_RestoreProjectPathItems)" Exclude="$(MSBuildProjectFullPath)" />
-            </ItemGroup>
-
-            <MSBuild
-                BuildInParallel="$(RestoreBuildInParallel)"
-                Projects="@(_GenerateRestoreGraphProjectEntryInput)"
-                Targets="_GenerateRestoreGraphProjectEntry"
-                Properties="$(_GenerateRestoreGraphProjectEntryInputProperties)">
-
-              <Output
-                  TaskParameter="TargetOutputs"
-                  ItemName="_RestoreGraphEntry" />
-            </MSBuild>
-
-            <MSBuild
-                BuildInParallel="$(RestoreBuildInParallel)"
-                Projects="@(_GenerateRestoreGraphProjectEntryInput)"
-                Targets="_GenerateProjectRestoreGraph"
-                Properties="$(_GenerateRestoreGraphProjectEntryInputProperties)">
-
-              <Output
-                  TaskParameter="TargetOutputs"
-                  ItemName="_RestoreGraphEntry" />
-            </MSBuild>
-          </Target>
-        """;
-
     public VirtualProjectBuildingCommand(
         string entryPointFileFullPath,
         MSBuildArgs msbuildArgs)
     {
         Debug.Assert(Path.IsPathFullyQualified(entryPointFileFullPath));
 
         EntryPointFileFullPath = entryPointFileFullPath;
-        MSBuildArgs = msbuildArgs;
+        MSBuildArgs = msbuildArgs.CloneWithAdditionalProperties(new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase)
+        {
+            // See https://github.com/dotnet/msbuild/blob/main/documentation/specs/build-nonexistent-projects-by-default.md.
+            { "_BuildNonexistentProjectsByDefault", bool.TrueString },
+            { "RestoreUseSkipNonexistentTargets", bool.FalseString },
+        }
+        .AsReadOnly());
     }
 
     public string EntryPointFileFullPath { get; }
@@ -856,7 +814,6 @@ public static void WriteProjectFile(
                     <Clean Include="{EscapeValue(artifactsPath)}/*" />
                   </ItemGroup>
 
-                  <!-- We need to explicitly import Sdk props/targets so we can override the targets below. -->
                 """);
 
             if (firstSdkVersion is null)
@@ -1049,11 +1006,7 @@ public static void WriteProjectFile(
                     """);
             }
 
-            writer.WriteLine($"""
-
-                {TargetOverrides}
-
-                """);
+            writer.WriteLine();
         }
 
         writer.WriteLine("""

test/dotnet.Tests/CommandTests/Run/RunFileTests.cs

@@ -1051,8 +1051,11 @@ public void BinaryLog_EvaluationData()
         new FileInfo(binaryLogPath).Should().Exist();
 
         var records = BinaryLog.ReadRecords(binaryLogPath).ToList();
-        records.Count(static r => r.Args is ProjectEvaluationStartedEventArgs).Should().Be(2);
-        records.Count(static r => r.Args is ProjectEvaluationFinishedEventArgs).Should().Be(2);
+
+        // There should be at least two - one for restore, one for build.
+        // But the restore targets might re-evaluate the project via inner MSBuild task invocations.
+        records.Count(static r => r.Args is ProjectEvaluationStartedEventArgs).Should().BeGreaterThanOrEqualTo(2);
+        records.Count(static r => r.Args is ProjectEvaluationFinishedEventArgs).Should().BeGreaterThanOrEqualTo(2);
     }
 
     /// <summary>
@@ -2650,7 +2653,6 @@ public void Api()
                         <Clean Include="/artifacts/*" />
                       </ItemGroup>
 
-                      <!-- We need to explicitly import Sdk props/targets so we can override the targets below. -->
                       <Import Project="Sdk.props" Sdk="Microsoft.NET.Sdk" />
                       <Import Project="Sdk.props" Sdk="Aspire.Hosting.Sdk" Version="9.1.0" />
 
@@ -2681,8 +2683,6 @@ public void Api()
                       <Import Project="Sdk.targets" Sdk="Microsoft.NET.Sdk" />
                       <Import Project="Sdk.targets" Sdk="Aspire.Hosting.Sdk" Version="9.1.0" />
 
-                    {VirtualProjectBuildingCommand.TargetOverrides}
-
                     </Project>
 
                     """)}},"Diagnostics":[]}
@@ -2720,7 +2720,6 @@ public void Api_Diagnostic_01()
                         <Clean Include="/artifacts/*" />
                       </ItemGroup>
 
-                      <!-- We need to explicitly import Sdk props/targets so we can override the targets below. -->
                       <Import Project="Sdk.props" Sdk="Microsoft.NET.Sdk" />
 
                       <PropertyGroup>
@@ -2744,8 +2743,6 @@ public void Api_Diagnostic_01()
 
                       <Import Project="Sdk.targets" Sdk="Microsoft.NET.Sdk" />
 
-                    {VirtualProjectBuildingCommand.TargetOverrides}
-
                     </Project>
 
                     """)}},"Diagnostics":
@@ -2787,7 +2784,6 @@ public void Api_Diagnostic_02()
                         <Clean Include="/artifacts/*" />
                       </ItemGroup>
 
-                      <!-- We need to explicitly import Sdk props/targets so we can override the targets below. -->
                       <Import Project="Sdk.props" Sdk="Microsoft.NET.Sdk" />
 
                       <PropertyGroup>
@@ -2811,8 +2807,6 @@ public void Api_Diagnostic_02()
 
                       <Import Project="Sdk.targets" Sdk="Microsoft.NET.Sdk" />
 
-                    {VirtualProjectBuildingCommand.TargetOverrides}
-
                     </Project>
 
                     """)}},"Diagnostics":