This time around here’s a simple way to fix a commit in the middle of your history before sharing it. The idea is to correct the existing commit and not to add new commits. (Thanks Aurélien for the idea!)
How it works
Let’s take the example of a working branch, feature / api. I’m not happy with commit B and want to fix it.
Create a fix commit from the last commit (HEAD). This commit is a bit special insofar as it is a temporary commit whose message will be created automatically (fixup)
Start an interactive rebase with the autosquash option. The fix commit will automatically be positioned to be merged with B.
Finalize the interactive rebase. The fixup commit is gone and my change has been included into B
Of course, since interactive rebase is a history rewrite tool, B commits and all its successors will get new SHA1. Be careful therefore to avoid rewriting an already pushed history (unless you are working alone on this branch).
Commands
Let’s see all this now in commands and from a small example!
1 – Identify the proper commit to be fixed
[ennael@zarafa lab-git (devel)]$ git log --oneline
af522a9 (HEAD -> devel) Add todo list
700b44e Add isc license file
6b7c25f Fix title et add more documentation
f3150b6 Add lib/fic4 library <----- commit to be fixed
1d05b4b Add lib/fic3 library
2 – Create the commit that will fix it
The fix will be committed using the –fixup = <SHA1 of the commit to be fixed>
[ennael@zarafa lab-git (devel)]$ vi lib/fic4 [ennael@zarafa lab-git (devel)]$ git add lib/fic4 [ennael@zarafa lab-git (devel)]$ git commit --fixup=f3150b6 [devel 5b360c8] fixup! Add lib/fic4 library 1 file changed, 1 insertion(+)
[ennael@zarafa lab-git (devel)]$ git log --oneline
5b360c8 (HEAD -> devel) fixup! Add lib/fic4 library
af522a9 Add todo list
700b44e Add isc license file
3 – Start interactive rebase
Do not forget –autosquash option
pick f3150b6 Add lib/fic4 library
fixup 5b360c8 fixup! Add lib/fic4 library
pick 6b7c25f Fix title et add more documentation
pick 700b44e Add isc license file
pick af522a9 Add todo list
4 – Tadaaaa here the result!
Voila, my fix has been integrated and my history has been rewritten!
[ennael@zarafa lab-git (devel)]$ git log --oneline 3eaccfd (HEAD -> devel) Add todo list 405aa43 Add isc license file e5d2b75 Fix title et add more documentation c4fa3b5 Add lib/fic4 library 1d05b4b Add lib/fic3 library
Nice! Let’s sum up.
Check the commit SHA1 to be fixed
git log --oneline
Create and commit your modification in a temporary commit
git commit --fixup=<SHA1 of the commit to be fixed>
Start interactive rebase
git rebase -i --autosquash <SHA1 of the commit to be fixed>~1
Validate
Use autosquash option by default with interactive rebase
git config --global rebase.autoSquash true