Fix incorrect failure notification in vcpkg publishing

eng/common/pipelines/templates/steps/git-push-changes.yml

@@ -25,11 +25,22 @@ steps:
       echo "##vso[task.setvariable variable=HasChanges]$false"
       echo "No changes so skipping code push"
     }
+
+    # Conditions determined that SkipCheckingForChanges is 'false', set this
+    # as a variable which can be passed into the "Push Changes" step
+    echo "##vso[task.setvariable variable=SkipCheckingForChanges]false"
   displayName: Check for changes
   condition: and(succeeded(), eq(${{ parameters.SkipCheckingForChanges }}, false))
   workingDirectory: ${{ parameters.WorkingDirectory }}
   ignoreLASTEXITCODE: true
 
+- pwsh: |
+    # Checking for changes was skipped, set a variable which can be passed into
+    # the "Push Changes" step
+    Write-Host "##vso[task.setvariable variable=SkipCheckingForChanges]true"
+  condition: and(succeeded(), eq(${{ parameters.SkipCheckingForChanges }}, true))
+  displayName: Set SkipCheckingForChanges to true
+
 - pwsh: |
     # Remove the repo owner from the front of the repo name if it exists there
     $repoName = "${{ parameters.TargetRepoName }}" -replace "^${{ parameters.TargetRepoOwner }}/", ""
@@ -39,6 +50,7 @@ steps:
   condition: succeeded()
   workingDirectory: ${{ parameters.WorkingDirectory }}
 
+# $(SkipCheckingForChanges) is set in an earlier step
 - task: PowerShell@2
   displayName: Push changes
   condition: and(succeeded(), eq(variables['HasChanges'], 'true'))
@@ -51,4 +63,4 @@ steps:
       -CommitMsg "${{ parameters.CommitMsg }}"
       -GitUrl "https://$(azuresdk-github-pat)@github.com/${{ parameters.BaseRepoOwner }}/$(RepoNameWithoutOwner).git"
       -PushArgs "${{ parameters.PushArgs }}"
-      -SkipCommit $${{ parameters.SkipCheckingForChanges }}
+      -SkipCommit $$(SkipCheckingForChanges)

eng/pipelines/templates/stages/archetype-cpp-release.yml

@@ -108,7 +108,7 @@ stages:
                       - pwsh: |
                           $branchName = "azure-sdk-for-cpp-${{ artifact.Name }}-$(Build.BuildId)"
                           if ('$(VcpkgForkBranchName)') {
-                            Write-Host "Using queue time branch name" 
+                            Write-Host "Using queue time branch name"
                             $branchName = '$(VcpkgForkBranchName)'
                           } 
                           Write-Host "##vso[task.setvariable variable=PrBranchName]$branchName"
@@ -177,21 +177,26 @@ stages:
                         parameters:
                           WorkingDirectory: $(Pipeline.Workspace)/vcpkg
 
-                      # SkipCheckingForChanges is true to skip the commit step
-                      # (which is already done by Update-VcpkgPort.ps1)
                       - template: /eng/common/pipelines/templates/steps/create-pull-request.yml
                         parameters:
+                          PushWorkingDirectoryChanges: false
                           RepoOwner: $(VcpkgPrRepoOwner)
                           RepoName: $(VcpkgPrRepoName)
                           WorkingDirectory: $(Pipeline.Workspace)/vcpkg
                           PrBranchName: $(PrBranchName)
                           PRTitle: $(PrTitle)
                           PRBody: Update vcpkg ports for Azure SDK release. This release may contain multiple ports.
-                          SkipCheckingForChanges: true
                           BaseBranchName: $(DefaultBranch)
                           OpenAsDraft: ${{ parameters.TestPipeline }}
                           PRLabels: "auto-merge"
                           CloseAfterOpenForTesting: '${{ parameters.TestPipeline }}'
+                          # If PublishToVcpkg is true, this template blindly attempts to create a PR. In that case
+                          # changes must already be checked into the branch for this template to succeed.
+                          # If PublishToVcpkg is false, the non-skipped checking for changes will result in no attempt
+                          # to open a PR because there will be no detected changes.
+                          # Use dictionary syntax because the template inserts the literal string into a `condition:`
+                          # element.
+                          SkipCheckingForChanges: variables['PublishToVcpkg']
 
                       - pwsh: |
                           $codeOwnersToNotify = $(Build.SourcesDirectory)/eng/common/scripts/get-codeowners.ps1 `