Gated Build does not perform merge

Would suggest:

1. Ensure Build Validation Is Set Up on the Target Branch

• Go to Repos > Branches > master > Branch Policies
• Under Build Validation, add your pipeline and make sure:
• Trigger on pull request is enabled
• Policy requirement is set to “Required”
• Build expires after is reasonable (e.g., 24 hours)

This ensures the build runs on the merged PR commit, not just the master.

2. Check Your YAML Trigger Settings

In your pipeline YAML, make sure you have:

trigger:
  branches:
    exclude:
      - "*"

pr:
  branches:
    include:
      - master

This disables CI builds and enables PR builds only when merging into master.

3. Use System.PullRequest.SourceBranch and System.PullRequest.TargetBranch

These variables help you confirm the build is running in the PR context. You can log them in your pipeline to verify:

steps:
- script: |
    echo "Source: $(System.PullRequest.SourceBranch)"
    echo "Target: $(System.PullRequest.TargetBranch)"

4. Avoid Classic Pipelines for PR Validation

If you're using classic pipelines, they may not handle PR merge commits properly. YAML pipelines are more reliable for gated builds.