Allow republishing of signed packages to Azure during official builds (#19169)

Author: wtgodbe

src/publish.proj

@@ -20,10 +20,7 @@
     <Error Condition="'@(ForPublishing)' == ''" Text="No items were found matching pattern '$(PublishPattern)'." />
   </Target>
 
-  <PropertyGroup>
-    <PublishPattern Condition="'$(PublishPattern)' == ''">$(PackagesBinDir)**\*.nupkg</PublishPattern>
-  </PropertyGroup>
-
+  <!-- Set up publish patterns for "final" package publish - that is, the pipeline packages we download & publish to myget during official builds -->
   <PropertyGroup>
     <PackageDownloadDirectory Condition="'$(DownloadDirectory)' == ''">$(PackagesDir)AzureTransfer\$(ConfigurationGroup)</PackageDownloadDirectory>
     <FinalPublishPattern>$(PackageDownloadDirectory)\**\*.nupkg</FinalPublishPattern>
@@ -33,6 +30,13 @@
     <OutDir>$(PackageDownloadDirectory)</OutDir>
   </PropertyGroup>
 
+  <PropertyGroup>
+    <!-- If we're re-publishing signed final packages, use the location of the downloaded pipeline packages -->
+    <PublishPattern Condition="'$(PublishPattern)' == '' and '$(RepublishSignedFinalPackages)' == 'true'">$(FinalPublishPattern)</PublishPattern>
+    <!-- Otherwise, publish the packages built locally -->
+    <PublishPattern Condition="'$(PublishPattern)' == ''">$(PackagesBinDir)**\*.nupkg</PublishPattern>
+  </PropertyGroup>
+
   <Target Name="GetPackagesToSign">
     <ItemGroup>
       <FilesToSign Include="$(FinalPublishPattern)" Exclude="$(FinalPublishPrivatePattern);$(FinalSymbolsPackagesPattern)">