Manually triggering Devops pipeline with pipeline resource should use latest resource pipeline run for that branch

Question

I have 2 pipelines in the same repo:

1. Build
2. Deploy

The Build pipeline is declared as a pipeline resource in the Deploy pipeline:

resources:
  pipelines:
  - pipeline: Build 
    source: BuildPipelineName
    trigger: true

When I run the Build pipeline, the Deploy pipeline is correctly triggered on the same branch. However, when I run the Deploy pipeline manually, it does not use the latest pipeline run from same branch.

I tried adding a couple of variations of the line below to the to the pipeline resource, but the variable does not expand:

branch: ${{ variables.Build.SourceBranchName }}

Is there any way to make this work?

Answer 1

Workaround that achieves the result I am looking for, but is not very elegant:

          - ${{ if ne(variables['Build.Reason'], 'ResourceTrigger')  }}:
            - task: DeleteFiles@1
              displayName: 'Remove downloaded artifacts from pipeline resource'
              inputs:
                SourceFolder: $(Pipeline.Workspace)

            - task: DownloadPipelineArtifact@2
              displayName: 'Download artifacts for branch'
              inputs:
                source: 'specific'
                project: 'myProject'
                pipeline: <BuildPipelineId>
                runVersion: 'latestFromBranch'    
                runBranch: $(Build.SourceBranch)