Git merge-base

How git merge-base is awesome and can help you out in difficult situations.

Transcript

1. DEMODAY git merge-base dive deeper Location, DD/MM/YYYY Name Surname, job title Title of the talk Git merge-base September 2nd, 2019 YOU SHOULD UNDERSTAND AND USE
2. DEMODAY git merge-base git merge-base finds the best common ancestor between two commits to use in a three-way merge. 02
3. DEMODAY git merge-base Ancestor is a parent or a parent of a parent (grandparent) or a great-grandparent, or a great-great-grandparent and so forth 03
4. DEMODAY git merge-base One common ancestor X is better than another common ancestor Y if Y is an ancestor of X. 04
5. DEMODAY git merge-base A common ancestor that does not have any better common ancestor is a best common ancestor, i.e. a merge base. 05
6. DEMODAY git merge base Example HERE YOU GO, HAVE AN 06
7. DEMODAY git merge-base “git merge-base A B” is 1: 07 o---o---o---B / ---2---1---o---o---o---A
8. DEMODAY git merge-base More than two commits as an argument? A B C ? 08
9. DEMODAY git merge-base Then the first commit (A) is the first argument, other commits (B C) will be merged* to create a second argument. 09
10. DEMODAY git merge-base “git merge-base A B C” is 1: 010 o----o----o----o----C / o----o----o----B / / ---2----1----o----o----o----A
11. DEMODAY git merge-base 02 Is awesome! GIT MERGE-BASE
12. DEMODAY git merge-base 02 Is useful! GIT MERGE-BASE
13. DEMODAY git merge-base For developing a fix to a release and dev branches at the same time. 013
14. DEMODAY git merge base Something has gone wrong with the release We need to fix it fast! IMAGINE THAT 014
15. DEMODAY git merge-base 1. ASAP: Fix the release 2. Merge the fix to dev so development can continue 015
16. DEMODAY git merge-base 016 o---release-x / ---o---o---o---o---o---dev
17. DEMODAY git merge-base 1. Create a fix branch at a merge base > git checkout -b fix-x $(git merge-base develop release-x) 017
18. DEMODAY git merge-base 018 o---release-x / ---o---o---o---o---o---dev | fix-x
19. DEMODAY git merge-base 2. Fix the in fix-x branch 3. At release-x merge in the fix > git merge fix-x 4. Create and release another binary 5. At dev merge in the fix > git merge fix-x 019
20. DEMODAY git merge-base One fix! 020
21. DEMODAY git merge-base Merged into two diverged branches! 021
22. DEMODAY git merge-base Did not get any merge conflicts! 022
23. DEMODAY git merge-base Everything would still be fine even if these branches would be merged between themselves. 023
24. DEMODAY git merge-base Because this is the same commit on both branches. 024
25. DEMODAY git merge-base PS: Avoid cherry-picking like the plague! It makes magic happen. When you least expect it .. 025
26. DEMODAY git merge-base 02 Is awesome! GIT MERGE-BASE
27. DEMODAY git merge base Something? OK, COOL.. DID I FORGET 027
28. DEMODAY git merge-base 028 git merge-base finds best common ancestor(s) between two commits to use in a three-way merge.
29. DEMODAY git merge base Bonus content SOME 029
30. DEMODAY git merge-base 030 How does Git know to merge changes?
31. DEMODAY git merge-base 031 .. amount = 15; .. .. amount = 3; .. File A File B
32. DEMODAY git merge-base 032 .. amount = 15; .. .. amount = 3; .. File A File B .. amount = 3; .. Common ancestor
33. DEMODAY git merge-base Questions, comments, Git stories .. THANKS! September 2nd, 2019