Can't determine pipeline which triggered a build

Question

I'm using Azure DevOps's multiple repository functionality, documented here:

https://docs.microsoft.com/en-us/azure/devops/pipelines/repos/multi-repo-checkout?view=azure-devops

I have my YAML file in one repo, and the pipeline points to that YAML. The YAML has a trigger set up for another repository resource, so that when that repo gets updated, the pipeline will be triggered:

 resources:
   repositories:
   - repository: MyRepo
     endpoint: 'MyRepos'
     type: git
     name: RepoName
     trigger:
     - '*'

The documentation claims that the 'Build.SourceBranch' variable will allow me to determine which branch in MyRepo triggered the pipeline build: "When an update to one of the repositories triggers a pipeline, then the following variables are set based on triggering repository"

However, this doesn't seem to be the case. No matter what branch triggers the build, 'Build.SourceBranch' is always 'refs/heads/master', presumably because the repo that holds the YAML has 'master' as its default branch.

I can't find any environment variable that gets set to the name of the branch that triggered the build, either. So how can I get the name of the branch that triggered the build? If there's no possible way, I think this needs to be added!

Jane Ma-MSFT Jane Ma-MSFT · Accepted Answer · 2020-08-24T08:47:48

The issue is:

According to the document, Build.SourceBranch is set based on triggering repository. However, its value is determined by repo in which the YAML file resides in practice.

I have done following tests. There are two repos, 'RepoA' and 'RepoB'. Both repos have two branches, 'master' and 'bran'. And the YAML file is in 'master' of 'RepoA'

Commit a change in 'bran' of 'RepoB'. The value of Build.SourceBranch is refs/heads/master. It is not consistent with the documentation.
Commit a change in 'bran' of 'RepoA'. The value of Build.SourceBranch is refs/heads/bran. It is consistent with the documentation.
Commit a change in 'master' of 'RepoB'. The value of Build.SourceBranch is refs/heads/master. It is consistent with the documentation.
Commit a change in 'master' of 'RepoA'. The value of Build.SourceBranch is refs/heads/master. It is consistent with the documentation.

Thus, if the build is triggered by 'RepoA', Build.SourceBranch can successfully represent the true branch. However, if the build is triggered by 'RepoB', the value of Build.SourceBranch are always refs/heads/master.

We have reported this issue to the product group.

Can't determine pipeline which triggered a build

1 Answers