Enable API compat validation

Author: RussKie

Directory.Build.props

@@ -47,9 +47,6 @@
     <Deterministic>true</Deterministic>
     <Features>debug-determinism</Features>
 
-    <!-- https://learn.microsoft.com/dotnet/fundamentals/package-validation/overview -->
-    <EnablePackageValidation>true</EnablePackageValidation>
-
     <EnableXlfLocalization>false</EnableXlfLocalization>
     <UpdateXlfOnBuild>false</UpdateXlfOnBuild>
 

eng/MSBuild/Packaging.targets

@@ -32,6 +32,15 @@
     <None Condition=" '$(IsPackable)' == 'true' and '$(IsShipping)' == 'true' " Include="README.md" Pack="true" PackagePath="\" />
   </ItemGroup>
 
+
+  <PropertyGroup Condition=" '$(IsPackable)' == 'true' and '$(IsShipping)' == 'true' and '$(Api)' != 'false' ">
+    <!-- https://learn.microsoft.com/dotnet/fundamentals/package-validation/overview -->
+    <EnablePackageValidation>true</EnablePackageValidation>
+    <!-- <EnablePackageValidation Condition=" '$(IsPackable)' == 'true' ">true</EnablePackageValidation> -->
+    <PackageValidationBaselineVersion Condition=" '$(Stage)' == 'normal' ">$(ApiCompatBaselineVersion)</PackageValidationBaselineVersion> 
+    <PackageValidationBaselineVersion Condition=" '$(Stage)' == 'preview' ">$(ApiCompatBaselineVersion)$(ApiCompatBaselineSuffix)</PackageValidationBaselineVersion> 
+  </PropertyGroup>
+
   <!-- Verify that the minimum supported TFM is actually used. -->
   <Target Name="_VerifyMinimumSupportedTfmForPackagingIsUsed"
           Condition="'$(IsPackable)' == 'true' and '$(DisableNETStandardCompatErrors)' != 'true'">

eng/Versions.props

@@ -6,7 +6,8 @@
     <PreReleaseVersionLabel>preview</PreReleaseVersionLabel>
     <PreReleaseVersionIteration>1</PreReleaseVersionIteration>
     <VersionPrefix>$(MajorVersion).$(MinorVersion).$(PatchVersion)</VersionPrefix>
-    <ValidateBaseline>true</ValidateBaseline>
+    <ApiCompatBaselineVersion>9.1.0</ApiCompatBaselineVersion>
+    <ApiCompatBaselineSuffix>-preview.1.25064.3</ApiCompatBaselineSuffix>
     <AssemblyVersion>$(MajorVersion).$(MinorVersion).0.0</AssemblyVersion>
     <!--
         When DotNetFinalVersionKind is set to 'release', this branch will produce stable outputs for 'Shipping' packages

src/ProjectTemplates/Directory.Build.props

@@ -5,5 +5,6 @@
     <NoWarn>$(NoWarn);SA1633;CS1591</NoWarn>
     <SkipAnalyzers>true</SkipAnalyzers>
     <ManagePackageVersionsCentrally>false</ManagePackageVersionsCentrally>
+    <Api>false</Api>
   </PropertyGroup>
 </Project>