Update GetPackageInfo aggregation to avoid race conditions with single file output (Azure#50539)

Author: Copilot

eng/Directory.Build.Common.targets

@@ -364,7 +364,7 @@
   <Target Name="RunApiCompat" DependsOnTargets="ValidateApiCompatForSrc" Condition="'$(ApiCompatVersion)' != ''">
   </Target>
 
-  <Target Name="GetPackageInfo">
+  <Target Name="GetPackageInfo" Returns="@(PackageInfoLine)">
     <PropertyGroup>
       <PackageIsNewSdk>false</PackageIsNewSdk>
       <PackageIsNewSdk Condition="'$(IsClientLibrary)' == 'true' or '$(IsFunctionsLibrary)' == 'true'">true</PackageIsNewSdk>
@@ -380,9 +380,14 @@
 
       <!-- Parse out the service directory based on the relative path to the sdk folder -->
       <ServiceDirectory><![CDATA[$([System.Text.RegularExpressions.Regex]::Replace($(PackageRootDirectory), '^.*[\\/]+sdk[\\/]+([^\\/]+).*$', '$1'))]]></ServiceDirectory>
+      
+      <!-- Format package info line for output -->
+      <PackageInfoText Condition="'$(IsShippingLibrary)' == 'true'">'$(PackageRootDirectory)' '$(ServiceDirectory)' '$(PackageId)' '$(VersionForProperties)' '$(PackageSdkType)' '$(PackageIsNewSdk)' '$(BaseOutputPath)'</PackageInfoText>
     </PropertyGroup>
 
-    <Message Condition="'$(IsShippingLibrary)' == 'true'" Text="'$(PackageRootDirectory)' '$(ServiceDirectory)' '$(PackageId)' '$(VersionForProperties)' '$(PackageSdkType)' '$(PackageIsNewSdk)' '$(BaseOutputPath)'" Importance="High" />
+    <ItemGroup Condition="'$(IsShippingLibrary)' == 'true'">
+      <PackageInfoLine Include="$(PackageInfoText)" />
+    </ItemGroup>
   </Target>
 
   <Target Name="GetCodeGenProjects" Returns="@(ProjectsToInclude)">

eng/scripts/Language-Settings.ps1

@@ -16,18 +16,35 @@ function Get-AllPackageInfoFromRepo($serviceDirectory)
   # Save-Package-Properties.ps1
   $shouldAddDevVersion = Get-Variable -Name 'addDevVersion' -ValueOnly -ErrorAction 'Ignore'
   $ServiceProj = Join-Path -Path $EngDir -ChildPath "service.proj"
-  Write-Host "dotnet msbuild /nologo /t:GetPackageInfo ""$ServiceProj"" /p:EnableCentralPackageVersions=False /p:ServiceDirectory=$serviceDirectory /p:AddDevVersion=$shouldAddDevVersion -tl:off"
+  $outputFilePath = Join-Path ([System.IO.Path]::GetTempPath()) "package-info-$([System.Guid]::NewGuid()).txt"
+  
+  Write-Host "dotnet msbuild /nologo /t:GetPackageInfo ""$ServiceProj"" /p:ServiceDirectory=$serviceDirectory /p:AddDevVersion=$shouldAddDevVersion /p:OutputProjectInfoListFilePath=""$outputFilePath"" -tl:off"
 
-  $msbuildOutput = dotnet msbuild `
+  dotnet msbuild `
     /nologo `
     /t:GetPackageInfo `
     "$ServiceProj" `
-    /p:EnableCentralPackageVersions=False `
     /p:ServiceDirectory=$serviceDirectory `
     /p:AddDevVersion=$shouldAddDevVersion `
-    -tl:off
+    /p:OutputProjectInfoListFilePath="$outputFilePath" `
+    -tl:off | Out-Host
+
+  # Check if msbuild succeeded
+  if ($LASTEXITCODE -ne 0) {
+    # Clean up temp file before failing
+    if (Test-Path $outputFilePath) {
+      $null = Remove-Item $outputFilePath -Force -ErrorAction SilentlyContinue
+    }
+    throw "MSBuild failed with exit code $LASTEXITCODE"
+  }
+
+  $packageInfoLines = @()
+  if (Test-Path $outputFilePath) {
+    $packageInfoLines = Get-Content $outputFilePath | Where-Object { $_ -and $_.Trim() }
+    $null = Remove-Item $outputFilePath -Force -ErrorAction SilentlyContinue
+  }
 
-  foreach ($projectOutput in $msbuildOutput)
+  foreach ($projectOutput in $packageInfoLines)
   {
     if (!$projectOutput) {
       Write-Verbose "Get-AllPackageInfoFromRepo::projectOutput was null or empty, skipping"

eng/service.proj

@@ -133,7 +133,20 @@
             Targets="GetPackageInfo"
             BuildInParallel="$(BuildInParallel)"
             SkipNonexistentProjects="false"
-            SkipNonexistentTargets="true" />
+            SkipNonexistentTargets="true">
+      <Output ItemName="PackageInfoLines" TaskParameter="TargetOutputs" />
+    </MSBuild>
+    
+    <!-- Deduplicate package info lines -->
+    <RemoveDuplicates Inputs="@(PackageInfoLines)">
+      <Output TaskParameter="Filtered" ItemName="PackageInfoLinesFiltered"/>
+    </RemoveDuplicates>
+    
+    <!-- Write aggregated package info to file if OutputProjectInfoListFilePath is specified -->
+    <WriteLinesToFile Condition="'$(OutputProjectInfoListFilePath)' != ''" 
+                      File="$(OutputProjectInfoListFilePath)" 
+                      Lines="@(PackageInfoLinesFiltered)" 
+                      Overwrite="true" />
   </Target>
 
   <Target Name="GetCodeGenProjects">