Merge pull request #43972 from sharwell/restrict-scope

Only run code style analyzers when nullable warnings are enabled

eng/targets/Imports.targets

@@ -25,6 +25,13 @@
       to only set in the inner builds, not the outer build where only $(TargetFrameworks) is defined.
     -->
     <DisableNullableWarnings Condition="'$(DisableNullableWarnings)' == '' AND $(TargetFrameworks.Contains('netcoreapp3.1')) AND '$(TargetFramework)' != '' AND '$(TargetFramework)' != 'netcoreapp3.1'">true</DisableNullableWarnings>
+
+    <!--
+      Disable code style analyzers in "older" targets for a multi-targeted project. These analyzers don't
+      impact the correctness of the output, so we avoid the performance overhead where it's easy to do so.
+    -->
+    <RoslynCheckCodeStyle Condition="'$(RoslynCheckCodeStyle)' == '' AND '$(DisableNullableWarnings)' == 'true'">false</RoslynCheckCodeStyle>
+    <RoslynCheckCodeStyle Condition="'$(RoslynCheckCodeStyle)' == '' AND ('$(ContinuousIntegrationBuild)' != 'true' OR '$(RoslynEnforceCodeStyle)' == 'true')">true</RoslynCheckCodeStyle>
   </PropertyGroup>
 
   <PropertyGroup Condition="'$(DisableNullableWarnings)' == 'true'">

eng/targets/Settings.props

@@ -17,7 +17,6 @@
     <DisableImplicitNuGetFallbackFolder>true</DisableImplicitNuGetFallbackFolder>
     <ToolsetPackagesDir>$(RepoRoot)build\ToolsetPackages\</ToolsetPackagesDir>
     <RoslynPortableTargetFrameworks>netcoreapp3.1;net472</RoslynPortableTargetFrameworks>
-    <RoslynCheckCodeStyle Condition="'$(ContinuousIntegrationBuild)' != 'true' or '$(RoslynEnforceCodeStyle)' == 'true'">true</RoslynCheckCodeStyle>
     <UseSharedCompilation>true</UseSharedCompilation>
 
     <Features>strict, IOperation</Features>
@@ -149,14 +148,14 @@
 
   <!-- Language-specific analyzer packages -->
   <Choose>
-    <When Condition="'$(Language)' == 'VB' and '$(RoslynCheckCodeStyle)' == 'true'">
-      <ItemGroup>
+    <When Condition="'$(Language)' == 'VB'">
+      <ItemGroup Condition="'$(RoslynCheckCodeStyle)' == 'true'">
         <PackageReference Include="Microsoft.CodeAnalysis.VisualBasic.CodeStyle" Version="$(MicrosoftCodeAnalysisVisualBasicCodeStyleVersion)" PrivateAssets="all" />
       </ItemGroup>
     </When>
 
-    <When Condition="'$(Language)' == 'C#' and '$(RoslynCheckCodeStyle)' == 'true'">
-      <ItemGroup>
+    <When Condition="'$(Language)' == 'C#'">
+      <ItemGroup Condition="'$(RoslynCheckCodeStyle)' == 'true'">
         <PackageReference Include="Microsoft.CodeAnalysis.CSharp.CodeStyle" Version="$(MicrosoftCodeAnalysisCSharpCodeStyleVersion)" PrivateAssets="all" />
       </ItemGroup>
     </When>