Git merge-base

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