---
title: Changed functions
description: Score only the functions a branch touched and fail the build when one is over the threshold.
---

Name the base revision of a branch, and poly-crap scores only the functions
the branch touched:

```sh
poly-crap --diff-base main --fail-above
```

It finds the merge base of the revision and `HEAD`, then takes committed
changes, staged and unstaged edits, and untracked files that `.gitignore` does
not cover. A function is selected when its current line range meets an added
or changed line. Its score still comes from the whole function and its current
coverage, so an edit to one line of an untested twenty-branch function fails
the gate. That is the point: the function is now yours.

Renamed files are followed. Deleted functions and binary files are ignored.
Git must be installed, `--path` must be inside a Git repository, and the
revision must resolve to a commit. In a pull request checkout the branch you
want is usually `origin/main`; see
[GitHub Actions](/gating/ci-recipes#github-actions).

:::note
`--diff-base` cannot be combined with `--baseline`.
:::