Set azure devops variable if any package reports are found and skip c…

…opy packages base on that (dotnet#32083)

* Set azure devops variable if any package reports are found

* Run target in CI as well

eng/pipelines/libraries/build-job.yml

@@ -153,7 +153,8 @@ jobs:
             inputs:
               sourceFolder: $(Build.SourcesDirectory)/artifacts/packages
               targetFolder: $(Build.ArtifactStagingDirectory)/artifacts/packages
-
+            condition: and(succeeded(), eq(variables['_librariesBuildProducedPackages'], true))
+
           - task: CopyFiles@2
             displayName: Prepare tmp assets to publish
             inputs:

src/libraries/packages.builds

@@ -70,4 +70,14 @@
   </Target>
 
   <Import Project="$(MSBuildThisFileDirectory)dir.traversal.targets" />
+
+  <Target Name="SetAzureDevOpsVariableForBuiltPackages"
+          Condition="'$(ContinuousIntegrationBuild)' == 'true'"
+          AfterTargets="BuildAllProjects">
+    <ItemGroup>
+      <_PackageReports Include="$(PackageReportDir)*.json" />
+    </ItemGroup>
+
+    <Message Condition="'@(_PackageReports)' != ''" Importance="High" Text="##vso[task.setvariable variable=_librariesBuildProducedPackages]true" />
+  </Target>
 </Project>