Awesome Git Commit Message

Why care about commit message anyways? What’s the need?

We write commit message to get a glance of development activity. Hence writing Awesome commit message might mean people scouring through git logs would be able to understand development activity better and faster.

some tips to write awesome git commit messages.

1. Use present tense: add awesome-package, not added …
2. Use preceding subsystem when applicable: registry: add theme foobar
3. 50 characters or less for the first line of your commit
4. Use of emoji is free¹

Anatomy of a commit message

It’s all connected

Examples of well crafted repositories

While many repositories’ logs look like the former, there are exceptions. The Linux kernel and Git itself are great examples. Look at Spring Boot, or any repository managed by Tim Pope.

Subject in IMPERATIVE

Explanation, what, why

imperative verbs

Soften

Add

Fix

Rewrite

Avoid

Close

Document

Refactor

Optimize

Reference

• To reference an issue: #123
• To reference a MR: !123
• To reference a snippet $123

strive for atomic commits

How to automate this process?

commit-msg

git commit hook to check/lint commit messages for issue IDs

sample OSM commit-msg hook

git log --pretty=oneline --abbrev-commit \
| cut --delimiter=' ' --fields=1 --complement \
| grep '\[.*\]' --count

github/commit-msg-linter npm

git staged | unstaged files

Even after git adding your files and later changing them, git may again ask you to stage your files! Why is that?

when you change a file which is already in the repository, you have to git add it again if you want it to be staged.

This allows you to commit only a subset of the changes you made since the last commit. For example, let’s say you have file a, file b and file c. You modify file a and file b but the changes are very different in nature and you don’t want all of them to be in one single commit. You issue

git add a
git commit file_a -m "bugfix, in a"
git add b
git commit file_b -m "new feature, in b"

# if you want to commit everything you can just type
git commit -a

How to unstage a file?

git rm --cached <filePath> does not unstage a file, it actually stages the removal of the file(s) from the repo (assuming it was already committed before) but leaves the file in your working tree (leaving you with an untracked file). will unstage the file for future commits also. It’s unstaged until it gets added again with git add .

git reset -- <filePath> will unstages the file in the current commit.

Gerrit

Web based code-review system. Read the code and comment on it. Learn from code

• First started as the code-review for Android project, 500+ repositories
• Has git ACLs, restricts branch, repo views.
• Code reviews are at commit level unlike branch level @github
• Single view for multiple repositories
• Gerrit intercepts the commit and make a code-review
• Reviwed changes are amended instead of new commit

• Pushing is gerrits speciality. When pushing for code-review

  git push origin HEAD:refs/for/master
  

• When by-passing code-review stage

  git push origin HEAD:master
  

Footnotes

Excellent git ppt Excellent gerrit code-review ppt