Add the ability to check for open pull request to a different repo.

eng/common/scripts/Delete-RemoteBranches.ps1

@@ -1,7 +1,15 @@
 param(
+  [Parameter(Mandatory = $true)]
   $RepoOwner,
+  # Use this if a pull request might have been opened from one repo against another.
+  # E.g Pull request opened from azure-sdk/azure-sdk prBranch --> Azure/azure-sdk baseBranch
+  [Parameter(Mandatory = $true)]
+  $ForkRepoOwner,
+  [Parameter(Mandatory = $true)]
   $RepoName,
+  [Parameter(Mandatory = $true)]
   $BranchPrefix,
+  [Parameter(Mandatory = $true)]
   $AuthToken
 )
 
@@ -23,6 +31,11 @@ foreach ($branch in $branches)
     $head = "${RepoOwner}/${RepoName}:${branchName}"
     LogDebug "Operating on branch [ $branchName ]"
     $pullRequests = Get-GitHubPullRequests -RepoOwner $RepoOwner -RepoName $RepoName -State "all" -Head $head -AuthToken $AuthToken
+
+    if ($ForkRepoOwner)
+    {
+      $pullRequests += Get-GitHubPullRequests -RepoOwner $ForkRepoOwner -RepoName $RepoName -State "all" -Head $head -AuthToken $AuthToken
+    }
   }
   catch
   {
@@ -31,16 +44,19 @@ foreach ($branch in $branches)
   }
 
   $openPullRequests = $pullRequests | ? { $_.State -eq "open" }
-
-  if ($openPullRequests.Count -eq 0)
+  if ($openPullRequests.Count -gt 0)
   {
-    LogDebug "Branch [ $branchName ] in repo [ $RepoName ] has no associated open Pull Request. Deleting Branch"
-    try{
-      Remove-GitHubSourceReferences -RepoOwner $RepoOwner -RepoName $RepoName -Ref ($branch.Remove(0,5)) -AuthToken $AuthToken
-    }
-    catch {
-      LogError "Remove-GitHubSourceReferences failed with exception:`n$_"
-      exit 1
-    }
+    LogDebug "Branch [ $branchName ] in repo [ $RepoName ] has open pull Requests. Skipping"
+    LogDebug $openPullRequests.url
+    continue
+  }
+
+  LogDebug "Branch [ $branchName ] in repo [ $RepoName ] has no associated open Pull Request. Deleting Branch"
+  try{
+    Remove-GitHubSourceReferences -RepoOwner $RepoOwner -RepoName $RepoName -Ref ($branch.Remove(0,5)) -AuthToken $AuthToken
+  }
+  catch {
+    LogError "Remove-GitHubSourceReferences failed with exception:`n$_"
+    exit 1
   }
 }