# Delete Squash-merged local Git Branches

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[![NPM Version](https://img.shields.io/npm/v/%40betaorbust%2Fgithub-loppers)](https://www.npmjs.com/package/@betaorbust/github-loppers) [![Hippocratic License HL3-FULL](https://img.shields.io/static/v1?label=Hippocratic%20License&message=HL3-FULL&labelColor=5e2751&color=bc8c3d)](https://github.com/betaorbust/github-loppers/blob/release/LICENSE)

![Shock at "git branches"](https://i.imgur.com/kua2UNA.gif)

A node utility to delete local branches that have already been merged into a
mainline via the squash-merge strategy. (Frequently
[used on Github](https://blog.github.com/2016-04-01-squash-your-commits/).)

With normal merge commits, you can run `git branch --merged` to get a list of
already-merged branches, but with squash-merge you end up with new commits that
contain your feature branch's work.

This util will find those already-squashed-and-merged branches and optionally
delete them.

<details>
<summary>Explanation of what's going on under the hood</summary>

- Gets the branch list by name
    - `git for-each-ref refs/heads/ --format=%(refname:short)`
- Then for each branch found:
    - Find the ancestor commit where ThisBranch left BaseBranch
        - `git merge-base <BaseBranch> <ThisBranch>`
    - Get the tree ID
        - `git rev-parse <ThisBranch>^{tree}`
    - Make up a temporary commit with the contents ThisBranch squashed together
        - `git commit-tree <TreeID> -p <AncestorSha> -m "Temp <ThisBranch>"`
    - See if the temp commit contents was already applied to upstream
        - `git cherry <BaseBranch> <TempPatchSha>`
    - If the above output starts with `-` the branch is a candidate for deletion
          </details>

### Usage:

**By default, this utility runs in dry mode. You will be prompted if you
actually want to run any destructive changes.**

The easiest way to use `@betaorbust/github-loppers` is via NPX:

```sh
cd ~/code/myProject             # Get to your local repo
npx @betaorbust/github-loppers   # Run the utility
```

which will `@betaorbust/github-loppers` directly so you can either list out or
delete your stale branches.

![Demo of running "npx https://github.com/betaorbust/github-loppers"](./demo.gif)

### Requirements:

- Node >= 18.18.0
- Git
- That the mainline branch your checking against is checked out locally.

### Acknowledgments

Git logic from @not-an-aardvark's awesome
[implementation](https://github.com/not-an-aardvark/git-delete-squashed).