Git Smudge/Clean Filter

Overview

A git smudge/clean filter auto-formats files on commit (clean) and optionally restores the original wrapping on checkout (smudge). This makes semantic line breaks transparent to collaborators who do not use snapper.

Setup

Configure the filter in your local git config:

git config filter.snapper.clean "snapper --format org"
git config filter.snapper.smudge cat

The smudge filter uses cat (passthrough), meaning checked-out files retain semantic line breaks. If you want to restore traditional wrapping on checkout, replace cat with a rewrapping command.

Activate via .gitattributes

Add to your repository’s .gitattributes:

*.org filter=snapper
*.tex filter=snapper
*.md  filter=snapper

Commit .gitattributes to share with collaborators. The filter only activates for people who have configured it locally.

Per-format filters

If you need different settings per format:

git config filter.snapper-org.clean "snapper --format org"
git config filter.snapper-org.smudge cat

git config filter.snapper-tex.clean "snapper --format latex"
git config filter.snapper-tex.smudge cat

*.org filter=snapper-org
*.tex filter=snapper-tex

Verifying the filter works

After setting up, stage a file and check the diff:

git diff --cached paper.org

The staged version should show sentence-per-line formatting even if the working copy uses traditional wrapping.