Azure DevOps Pipeline Fails to Trigger on External Repository Changes

Below are a few common gotchas and steps to troubleshoot multi‐repo triggers in Azure Pipelines:

1. Verify Repository Authorization
   Even though you linked the pipeline to the resource repository, you need to ensure that the repository resource is explicitly authorized. In your pipeline’s run summary (or via the pipeline settings) check that the resource repository “test-repo” is approved. If it isn’t yet authorized, any push won’t trigger the pipeline.

2. Ensure Correct Branch Identification
   Double‑check that the branch you refer to really exists and that its name exactly matches the filter. For example, if your branch is named “testname” make sure the repository indeed uses that name and that it’s not “refs/heads/testname” somewhere else. Sometimes it helps to be explicit:

   YAMLCopied
   resources:
     repositories:
     - repository: test-repo
       type: git
       name: test-project/test-repo
       ref: refs/heads/testname
       trigger:
         branches:
           include:
           - testname

3. Check Pipeline Settings for Resource Triggers
   Although you’ve set the self‑repository trigger to none, be sure that multi‑repo triggers are enabled in your project settings. In some cases, settings such as “Limit job authorization scope to current project” may impact resource repositories; try temporarily removing or adjusting that setting to see if it helps.

4. Confirm That Your YAML Structure Is Correct
   Your YAML structure looks similar to the docs. Just confirm that indentation is correct and that no other override in your pipeline definition is blocking the resource trigger.

5. Review Documentation Notes
   According to the docs, when using multi‑repo checkout triggers the pipeline is only triggered on changes to the external repository if the branch filter exactly matches the incoming push. Also, note that changes made in your external repository will only trigger the pipeline if you indeed push a commit that matches the branch filter.

If, after confirming these points, it still does not trigger, try deleting and re‑authorizing the resource repository under the pipeline’s “Manage Resources” section. Often, re‑authorization clears out any stale permissions that might block repository resource build triggers.

By ensuring proper authorization, exact branch matching (using either “testname” or a full ref) and verifying project settings, you should be able to get the trigger working as expected.