Merge pull request #54143 from mavasani/SkipAnalyzersOnIndirectBuild

Add functionality to enable skipping analyzers for implicitly trigger…

src/Compilers/Core/MSBuildTask/ErrorString.resx

@@ -214,4 +214,7 @@
   <data name="General_UnableToReadFile" xml:space="preserve">
     <value>File "{0}" could not be read: {1}</value>
   </data>
+  <data name="ImplicitlySkipAnalyzersMessage" xml:space="preserve">
+    <value>Skipping analyzers to speed up the build. You can execute 'Build' or 'Rebuild' command to run analyzers.</value>
+  </data>
 </root>

src/Compilers/Core/MSBuildTask/Microsoft.Managed.Core.targets

@@ -50,10 +50,19 @@
     </PropertyGroup>
   </Target>
 
+  <!--
+    ========================
+    SkipAnalyzers Support
+    ========================
+    
+    -->
+  <UsingTask TaskName="Microsoft.CodeAnalysis.BuildTasks.ShowMessageForImplicitlySkipAnalyzers" AssemblyFile="$(MSBuildThisFileDirectory)Microsoft.Build.Tasks.CodeAnalysis.dll" />
+
   <Target Name="_ComputeSkipAnalyzers" BeforeTargets="CoreCompile">
-    <!-- First, force clear non-user facing property '_SkipAnalyzers'. -->
+    <!-- First, force clear non-user facing properties '_SkipAnalyzers' and '_ImplicitlySkipAnalyzers'. -->
     <PropertyGroup>
       <_SkipAnalyzers></_SkipAnalyzers>
+      <_ImplicitlySkipAnalyzers></_ImplicitlySkipAnalyzers>
     </PropertyGroup>
 
     <!--
@@ -70,6 +79,41 @@
                               ('$(RunAnalyzers)' == '' and '$(RunAnalyzersDuringBuild)' == 'false')">
       <_SkipAnalyzers>true</_SkipAnalyzers>
     </PropertyGroup>
+
+    <!-- PERF: For builds which are indirectly triggered inside Visual Studio from commands 
+               such as from 'Run Tests' or 'Start Debugging', we implicitly skip analyzers to speed up the build.
+               We only do so by default when 'TreatWarningsAsErrors' is not 'true'. For the scenario where
+			         'TreatWarningsAsErrors' is 'true', users can explicitly enable this functionality by setting
+			         'OptimizeImplicitlyTriggeredBuild' to 'true'.
+    -->
+    <PropertyGroup Condition="'$(_SkipAnalyzers)' == '' and
+                              '$(IsImplicitlyTriggeredBuild)' == 'true' and
+                              ('$(TreatWarningsAsErrors)' != 'true' or '$(OptimizeImplicitlyTriggeredBuild)' == 'true')">
+      <_ImplicitlySkipAnalyzers>true</_ImplicitlySkipAnalyzers>
+      <_SkipAnalyzers>true</_SkipAnalyzers>
+    </PropertyGroup>
+
+    <!-- Display a message to inform the users about us implicitly skipping analyzers for speeding up indirect builds. -->
+    <ShowMessageForImplicitlySkipAnalyzers Condition="'$(_ImplicitlySkipAnalyzers)' == 'true'"/>
+
+    <!-- Semaphore file to indicate the time stamp for last build with skipAnalyzers flag. -->
+    <PropertyGroup>
+      <_LastBuildWithSkipAnalyzers>$(IntermediateOutputPath)$(MSBuildProjectFile).BuildWithSkipAnalyzers</_LastBuildWithSkipAnalyzers>
+    </PropertyGroup>
+
+    <!-- '_LastBuildWithSkipAnalyzers' semaphore file, if exists, is passed as custom additional file input to builds without skipAnalyzers flag to ensure correct incremental builds. 
+	       Additionally, we need to pass this file as an 'UpToDateCheckInput' item with 'Kind = ImplicitBuild' for project system's fast-upto-date check to work correctly.
+		     See https://github.com/dotnet/project-system/issues/7290 for details.
+	  -->
+    <ItemGroup Condition="Exists('$(_LastBuildWithSkipAnalyzers)')">
+      <CustomAdditionalCompileInputs Include="$(_LastBuildWithSkipAnalyzers)" Condition="'$(_SkipAnalyzers)' != 'true'"/>
+      <UpToDateCheckInput Include="$(_LastBuildWithSkipAnalyzers)" Kind="ImplicitBuild"/>
+    </ItemGroup>
+  </Target>
+
+  <!-- We touch and create a semaphore file after build to indicate the time stamp for last build with skipAnalyzers flag. -->
+  <Target Name="_TouchLastBuildWithSkipAnalyzers" Condition="'$(_SkipAnalyzers)' == 'true'" AfterTargets="CoreCompile">
+    <Touch AlwaysCreate="true" Files="$(_LastBuildWithSkipAnalyzers)"/>
   </Target>
 
   <!--

src/Compilers/Core/MSBuildTask/ShowMessageForImplicitlySkipAnalyzers.cs

@@ -0,0 +1,25 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System;
+using System.Linq;
+using System.Text;
+using Microsoft.Build.Framework;
+using Microsoft.Build.Utilities;
+using Roslyn.Utilities;
+
+namespace Microsoft.CodeAnalysis.BuildTasks
+{
+    /// <summary>
+    /// Logs a localizable message for implicitly skipping analyzers for implicitly triggered builds.
+    /// </summary>
+    public sealed class ShowMessageForImplicitlySkipAnalyzers : Task
+    {
+        public override bool Execute()
+        {
+            Log.LogMessage(MessageImportance.High, ErrorString.ImplicitlySkipAnalyzersMessage);
+            return true;
+        }
+    }
+}