Upgrade to more recent .NET SDK (#21017)

* Update SDK to preview.5.20251.2
  - includes support for the `net5.0` TFM
  - includes fix for `$(PublishDepsFilePath)`
  - includes fix for incorrect NU5118 warnings when `'$(PackAsTool)' == 'true'`
* !!temporary!! Suppress NU5129 warnings
  - build/ and buildTransitive/ naming conventions do not treat TFMs as equivalent
* Run `InjectRequestHandlerOnPublish` later
  - late enough for .deps file to exist i.e. after the `CopyFilesToPublishDirectory` target
  - `AfterTargets` is a bit flaky; use `BeforeTargets` with empty targets instead
* Always add `@(AssemblyAttribute)` items before they are processed
  - use `BeforeTargets="GetAssemblyAttributes"` for consistently throughout the repo

global.json

@@ -1,9 +1,9 @@
 {
   "sdk": {
-    "version": "5.0.100-preview.2.20120.3"
+    "version": "5.0.100-preview.5.20251.2"
   },
   "tools": {
-    "dotnet": "5.0.100-preview.2.20120.3",
+    "dotnet": "5.0.100-preview.5.20251.2",
     "runtimes": {
       "dotnet/x64": [
         "$(MicrosoftNETCoreAppInternalPackageVersion)"

src/Mvc/Mvc.Razor.RuntimeCompilation/src/Microsoft.AspNetCore.Mvc.Razor.RuntimeCompilation.csproj

@@ -1,9 +1,12 @@
 <Project Sdk="Microsoft.NET.Sdk">
-
   <PropertyGroup>
     <Description>Runtime compilation support for Razor views and Razor Pages in ASP.NET Core MVC.</Description>
     <TargetFramework>$(DefaultNetCoreTargetFramework)</TargetFramework>
     <NoWarn>$(NoWarn);CS1591</NoWarn>
+
+    <!-- !!! Temporary workaround while we switch TFMs. -->
+    <NoWarn>$(NoWarn);NU5129</NoWarn>
+
     <GenerateDocumentationFile>true</GenerateDocumentationFile>
     <PackageTags>aspnetcore;aspnetcoremvc;razor</PackageTags>
     <IsPackable>true</IsPackable>

src/Mvc/Mvc.Testing/src/Microsoft.AspNetCore.Mvc.Testing.csproj

@@ -1,9 +1,12 @@
 <Project Sdk="Microsoft.NET.Sdk">
-
   <PropertyGroup>
     <Description>Support for writing functional tests for MVC applications.</Description>
     <TargetFramework>$(DefaultNetCoreTargetFramework)</TargetFramework>
     <NoWarn>$(NoWarn);CS1591</NoWarn>
+
+    <!-- !!! Temporary workaround while we switch TFMs. -->
+    <NoWarn>$(NoWarn);NU5129</NoWarn>
+
     <GenerateDocumentationFile>true</GenerateDocumentationFile>
     <PackageTags>aspnetcore;aspnetcoremvc;aspnetcoremvctesting</PackageTags>
     <IsPackable>true</IsPackable>
@@ -21,5 +24,4 @@
   <ItemGroup>
     <Content Include="Microsoft.AspNetCore.Mvc.Testing.targets" Pack="true" PackagePath="build/$(TargetFramework)/" />
   </ItemGroup>
-
 </Project>

src/Mvc/Mvc.Testing/src/Microsoft.AspNetCore.Mvc.Testing.targets

@@ -23,7 +23,7 @@
       </ItemGroup>
     </Target>
 
-  <Target Name="_AddContentRootForProjectReferences" BeforeTargets="BeforeCompile" DependsOnTargets="_ResolveMvcTestProjectReferences">
+  <Target Name="_AddContentRootForProjectReferences" BeforeTargets="GetAssemblyAttributes" DependsOnTargets="_ResolveMvcTestProjectReferences">
     <ItemGroup>
       <WebApplicationFactoryContentRootAttribute
         Condition="'%(_ContentRootProjectReferences.Identity)' != ''"
@@ -35,7 +35,7 @@
     </ItemGroup>
 
     <ItemGroup>
-      <AssemblyAttribute 
+      <AssemblyAttribute
         Condition=" '%(WebApplicationFactoryContentRootAttribute.Identity)' != '' "
         Include="Microsoft.AspNetCore.Mvc.Testing.WebApplicationFactoryContentRootAttribute">
         <_Parameter1>%(WebApplicationFactoryContentRootAttribute.AssemblyName)</_Parameter1>
@@ -55,5 +55,5 @@
 
     <Copy SourceFiles="%(DepsFilePaths.FullPath)" DestinationFolder="$(OutDir)" Condition="Exists('%(DepsFilePaths.FullPath)')" />
   </Target>
-    
+
 </Project>

src/ProjectTemplates/BlazorTemplates.Tests/BlazorTemplates.Tests.csproj

@@ -70,7 +70,7 @@
     </AssemblyAttribute>
   </ItemGroup>
 
-  <Target Name="PrepareForTest" BeforeTargets="CoreCompile" Condition="$(DesignTimeBuild) != true">
+  <Target Name="PrepareForTest" BeforeTargets="GetAssemblyAttributes" Condition="$(DesignTimeBuild) != true">
     <PropertyGroup>
       <TestTemplateCreationFolder>$([MSBuild]::NormalizePath('$(OutputPath)$(TestTemplateCreationFolder)'))</TestTemplateCreationFolder>
       <TestTemplateTestsProps>$(TestTemplateCreationFolder)$(TestTemplateTestsProps)</TestTemplateTestsProps>

src/ProjectTemplates/test/ProjectTemplates.Tests.csproj

@@ -73,7 +73,7 @@
     </AssemblyAttribute>
   </ItemGroup>
 
-  <Target Name="PrepareForTest" BeforeTargets="CoreCompile" Condition="$(DesignTimeBuild) != true">
+  <Target Name="PrepareForTest" BeforeTargets="GetAssemblyAttributes" Condition="$(DesignTimeBuild) != true">
     <PropertyGroup>
       <TestTemplateCreationFolder>$([MSBuild]::NormalizePath('$(OutputPath)$(TestTemplateCreationFolder)'))</TestTemplateCreationFolder>
       <TestTemplateTestsProps>$(TestTemplateCreationFolder)$(TestTemplateTestsProps)</TestTemplateTestsProps>

src/Servers/IIS/build/testsite.props

@@ -59,17 +59,27 @@
     </PropertyGroup>
   </Target>
 
+  <!--
+    GenerateBuildDependencyFile creates the .deps file used here. BuildDepsJson and CoreBuild are empty targets marking
+    the end of processes using the GenerateBuildDependencyFile target.
+  -->
   <Target Name="InjectRequestHandler"
           Condition=" '$(InProcessTestSite)' == 'true' AND '$(BuildIisNativeProjects)' == 'true' AND '$(TargetFrameworkIdentifier)' != '.NETFramework'"
-          AfterTargets="GenerateBuildDependencyFile"
-          DependsOnTargets="PrepareInjectionApp">
+          BeforeTargets="BuildDepsJson;CoreBuild"
+          DependsOnTargets="GenerateBuildDependencyFile;PrepareInjectionApp">
     <Exec Command="$(InjectDepsApp) &quot;$(ProjectDepsFilePath)&quot; $(RuntimeIdentifier) " />
   </Target>
 
+  <!--
+    GeneratePublishDependencyFile creates an intermediate .deps file copied soon after into the publish folder.
+    CopyFilesToPublishDirectory is an empty target marking the end of all copies into the publish folder, including the
+    .deps file and native assets. Publish is an empty target marking the end of the entire process.
+    (GenerateSingleFileBundle also uses the intermediate .desp file but only in single-file publish cases ignored here.)
+  -->
   <Target Name="InjectRequestHandlerOnPublish"
           Condition=" '$(InProcessTestSite)' == 'true' AND '$(BuildIisNativeProjects)' == 'true' AND '$(TargetFrameworkIdentifier)' != '.NETFramework'"
-          AfterTargets="GeneratePublishDependencyFile"
-          DependsOnTargets="PrepareInjectionApp">
+          BeforeTargets="Publish"
+          DependsOnTargets="GeneratePublishDependencyFile;CopyFilesToPublishDirectory;PrepareInjectionApp">
     <Exec Command="$(InjectDepsApp) &quot;$(PublishDepsFilePath)&quot; $(RuntimeIdentifier) " />
   </Target>
 

src/Shared/E2ETesting/E2ETesting.targets

@@ -77,7 +77,7 @@
     </ItemGroup>
   </Target>
 
-  <Target Name="_AddTestProjectMetadataAttributes" BeforeTargets="BeforeCompile" DependsOnTargets="_ResolveTestProjectReferences">
+  <Target Name="_AddTestProjectMetadataAttributes" BeforeTargets="GetAssemblyAttributes" DependsOnTargets="_ResolveTestProjectReferences">
     <ItemGroup>
       <_ContentRootMetadata
         Condition="'%(_ContentRootProjectReferences.Identity)' != ''"
@@ -98,7 +98,7 @@
     </ItemGroup>
   </Target>
 
-  <Target Name="_AddSeleniumSupportedMetadataAttribute" BeforeTargets="BeforeCompile">
+  <Target Name="_AddSeleniumSupportedMetadataAttribute" BeforeTargets="GetAssemblyAttributes">
     <PropertyGroup>
       <_SeleniumE2ETestsSupportedAttributeValue>false</_SeleniumE2ETestsSupportedAttributeValue>
       <_SeleniumE2ETestsSupportedAttributeValue Condition="'$(SeleniumE2ETestsSupported)' == 'true'">true</_SeleniumE2ETestsSupportedAttributeValue>
@@ -118,7 +118,7 @@
     </ItemGroup>
   </Target>
 
-  <Target Name="_AddProcessTrackingMetadataAttribute" BeforeTargets="BeforeCompile">
+  <Target Name="_AddProcessTrackingMetadataAttribute" BeforeTargets="GetAssemblyAttributes">
     <MakeDir Directories="$(SeleniumProcessTrackingFolder)" />
     <ItemGroup>
       <AssemblyAttribute