Azure DevOps Repos branch build policies not triggering when expected in PRs – Solved

I recently hit a problem with builds triggered by branch policies in Azure DevOps Repos. With the help of Microsoft I found out the problem and I thought it worth writing up uncase others hit the issue.

Setup

Folders

Assume you have a Git repo with source for the UI, backend Services and common code in sub folders

/ [root]
     UI
     Services
     Common

Branch Policies

On the Master branch there are a policies of running

  • one build for anything in the UI folder/project or common folder/project
  • and a different build for anything in the Services folder/project or common folder/project

These build were filtered by path using the filters

/UX; /Common
/Services; /Common

The Issue

I discovered the problem by doing the following

  • Create a PR for some work that effects the UI project
  • As expected the UI build triggers
  • Update the PR with a second commit for the Services code
  • The Service build is not triggered

The Solution

The fix was simple it turns out. Remove the spaces from the filter paths so they become

/UX;/Common
/Services;/Common

Once this was done the builds triggered as expected.

Thanks again to the Azure DevOps Product Group for the help