Summary

In the Midstream repositories for our CPaaS builds, upstream_sources indicates the Git source location and sha to be rendered and built downstream.  Currently, upstream_sources has the related git sha populated from our upstream pipeline (ACM) or backplane-pipelie (MCE) repo. 

The issue is - upstream_sources is sensitive not only to the Git source location and Git sha, but also the git branch on which it will find the sha because, functionally, the downstream tooling does a shallow clone of the upstream repo - only cloning the target branch.  

As a result, we need to render not only the git sha, but also the source git branch into upstream_sources as part of our manifest rendering process.  As a result, we first need to track the source Git branch in our pipeline and backplane-pipeline manifests.  

Goals

• Include the source repo branch in the pipeline manifest and tolerate that new value throughout the pipeline tooling