Git Strategies

An overview on merge and rebase as well as some of the different git workflows a team can adopt based on them. Also goes through some common anti-patterns and how to avoid them.

Transcript

1. Git strategies A history of conflicts, and how to approach them 1
2. Agenda Git rebase Git merge Team git workflows Common anti-patterns Useful tools 2
3. Git rebase Rewritting history since 2005 3
4. What is rebase? Reapply commits on top of another base tip “ “ 4
5. So... why rebase? Modifying broken commits, ergo eliminating bugged commits Rearranging content between commits, ergo more meaningful commits Keeping a clean history, ergo... clean history :) 5
6. How do I rebase? --A---B---C topic / D---E---F---G master $ git checkout topic $ git rebase master topic --A'--B'--C' topic / D---E---F---G master 6
7. The powerhouse: interactive rebase The power to rewrite history literally: it allows you to alter commits rather than only moving them. It’s based on git commit --amend Interactive mode further allows you to also squash the commits, for a cleaner history. 7
8. Rebasing caveats Rewrites history – careful with rebasing on public branches Merge conflicts are more frequent Commits can be lost in interactive mode 8
9. Git merge Eventually, all rivers lead to the sea 9
10. What is merge? Join two or more development histories together “ “ 10
11. What's the difference with rebase? Merge commits are unique against other commits in the fact that they have two parent commits. History is completely preserved, instead of rewritting it. 11
12. Why would I want to merge? Incorporate the commits from the named branch into the current branch without loosing history 12
13. Merging in a nutshell A---B---C topic / D---E---F---G master $ git checkout master $ git merge topic A---B---C topic / \ D---E---F---G---H master 13
14. Further details Git merge will combine multiple sequences of commits into one unified history. [...] git merge takes two commit pointers, usually the branch tips, and will find a common base commit between them. Once Git finds a common base commit it will create a new "merge commit" that combines the changes of each queued merge commit sequence. If a piece of data that is changed in both histories git will be unable to automatically combine them. Fast-forward vs 3-way merge 14
15. Defining a workflow Life only gives us options, choice is always ours. 15
16. Trunk-based development Whole team develops to shared branch called trunk (!!) Short lived feature branches Release branches When? Just starting up/need quick iterations Mostly senior developers When not? Open source projects Mostly junior developers 16
18. Gitflow Two main branches: develop and main . Features are developed by branching develop and are reviewed before merging. Releases are merges from develop to master . When? The opposite scenarios to Trunk-based development. In other words, any scenario where branch micromanagement could be an asset rather than a burden. 18
20. And where do merge/rebase fit in? Both of these commands are designed to integrate changes from one branch into another branch—they just do it in very different ways. The golden rule of git rebase is to never use it on public branches. Nonetheless, the team decides. 20
21. The extra mile The noblest pleasure is the joy of understanding. 21
22. Some anti-patterns to be aware of Pushing every commit Can you jump to any commit? Long living branches Complicated commit log Using GUIs Commit early, commit often, perfect later, publish once. credits: @lemiorhan 22
23. Further tools to hone our craft git bisect git log git cherry-pick git reflog git hooks 23
24. Thank you all! Workshop Repository hojasdemanzano Manzanit0 24