Git Shit Done - HackMD

# GIT SHIT DONE --- ### Who is this talk for? - devs with (chronic) git pain - all git users really - you ---  ##### Takeaway #1 Commits record state, not changes! --- ### Wait a second... - git show clearly shows me a diff - git rebase talks about applying commits - what about git cherry-pick? --- ### Commits, but simplified - metadata such as author & message - one or more parents (merge commits) - filesystem state: trees and blobs --- ### Commands, but simplified - diffs are always calculated - commands often expand id to mean id~..id --- ### Rebasing, but simplified - rebasing means running ```bash git format-patch id~..id git apply ``` - sequentially for each commit - onto the target or the previous result ---  ##### Takeaway #2 Commits are referenced by different pointers ##### (have a read some time: man gitrevisions) --- ### What's on the Menu: - branch and ref names such as origin/main - @ or HEAD - generational selectors - ~ selects the previous generation - ^n selects the n'th parent - ~3 == ^1^1^1 --- ### What's on the Menu: - commit message selectors - :/api, :/^test, :/!-feat - time and history based selectors - main@{yesterday} - this is what's managed by git reflog! --- ### Try those some time ```cpp # edit last two commits git rebase -i @~~ # look at your week so far (independent of commit time!) git log main@{last monday}.. # graph some commits, add common parents and mark dupes git log --graph --boundary --cherry-mark main...feature # fixup the last commit that starts with test git commit --fixup :/^test ``` ---   ##### Takeaway #3 Review feedback does not need to be a single odd commit --- ### Reviews and Atomic Commits - Fixup allows us to add requested changes to the correct commit - Autosquash those during rebase -i (it's a config option) - [git absorb](https://github.com/tummychow/git-absorb) determines the fixup targets automatically! --- ### Absorbing Commits 1. Given a change A, calculate a patch B for @~..@ 2. Apply onto @~ - first A, then B - first B, then A 3. Equal results? A and B **commute** - reset @ to @~ and goto 1. 4. Different results? Fixup commit x, next change --- ### Thank you! :rocket: