Scan Only Changed Files in CI

On large repositories, scanning everything on every pull request is slow and noisy. The --changed-only flag focuses the scan on modified files, giving faster and more relevant feedback while keeping full scans for the default branch and nightly runs.

Prerequisites

• Vibgrate running on pull requests.
• Enough git history checked out so the diff base is available.

Steps

1. Fetch git history

CI checkouts are often shallow. Fetch enough history so the scanner can compute what changed.

      - uses: actions/checkout@v4
        with:
          fetch-depth: 0

2. Run a changed-only scan

Add --changed-only to limit the scan to files modified in the branch.

vg scan --changed-only

The DriftScore and findings reflect only the changed surface, so reviewers focus on what the PR actually touches.

3. Use it on pull requests

Wire the changed-only scan into the pull request job, while keeping a full vg scan on the default branch.

      - run: npx @vibgrate/cli scan --changed-only

4. Combine with a gate

Add a budget or severity gate so changed-only runs can still block a merge.

vg scan --changed-only --drift-budget 60

5. Verify the scope

Open a PR that changes a single file and confirm the scan output references only the changed area, not the whole repository.

Verification

Compare a full vg scan against vg scan --changed-only on the same PR; the changed-only run should be faster and report findings scoped to the diff. Exit codes still drive any gate you attach.

vg scan --changed-only --drift-budget 60

Next Steps

• Keep a full scan on the default branch and nightly schedule.
• Post changed-only results as a PR comment.
• Push full results to Vibgrate Cloud with vg scan --push.