I just read amending a single file in a past commit in git but unfortunately the accepted solution 'reorders' the commits, which is not what I want. So here's my question:
Every now and then, I notice a bug in my code while working on an (unrelated) feature. A quick
git blame
git stash # temporarily put my work aside
git rebase -i <bad_commit>~1 # rebase one step before the bad commit
# mark broken commit for editing
vim <affected_sources> # fix the bug
git add <affected_sources> # stage fixes
git commit -C <bad_commit> # commit fixes using same log message as before
git rebase --continue # base all later changes onto this
vim <affected_sources> # fix bug
git add -p <affected_sources> # Mark my 'fixup' hungs for staging
git fixup <bad_commit> # amend the specified commit with staged changes,
# rebase any successors of bad commit on rewritten
# commit.
A while ago, a new --fixup
argument was added to git commit
which can be used to construct a commit with a log message suitable for git rebase --interactive --autosquash
. So the simplest way to fixup a past commit is now:
$ git add ... # Stage a fix
$ git commit --fixup=a0b1c2d3 # Perform the commit to fix broken a0b1c2d3
$ git rebase -i --autosquash a0b1c2d3~1 # Now merge fixup commit into broken commit
Here's a little Python script I wrote a while ago which implements this git fixup
logic I hoped for in my original question. The script assumes that you staged some changes and then applies those changes to the given commit.
NOTE: This script is Windows-specific; it looks for git.exe
and sets the GIT_EDITOR
environment variable using set
. Adjust this as needed for other operating systems.
Using this script I can implement precisely the 'fix broken sources, stage fixes, run git fixup ' workflow I asked for:
#!/usr/bin/env python
from subprocess import call
import sys
# Taken from http://stackoverflow.com/questions/377017/test-if-executable-exists-in python
def which(program):
import os
def is_exe(fpath):
return os.path.exists(fpath) and os.access(fpath, os.X_OK)
fpath, fname = os.path.split(program)
if fpath:
if is_exe(program):
return program
else:
for path in os.environ["PATH"].split(os.pathsep):
exe_file = os.path.join(path, program)
if is_exe(exe_file):
return exe_file
return None
if len(sys.argv) != 2:
print "Usage: git fixup <commit>"
sys.exit(1)
git = which("git.exe")
if not git:
print "git-fixup: failed to locate git executable"
sys.exit(2)
broken_commit = sys.argv[1]
if call([git, "rev-parse", "--verify", "--quiet", broken_commit]) != 0:
print "git-fixup: %s is not a valid commit" % broken_commit
sys.exit(3)
if call([git, "diff", "--staged", "--quiet"]) == 0:
print "git-fixup: cannot fixup past commit; no fix staged."
sys.exit(4)
if call([git, "diff", "--quiet"]) != 0:
print "git-fixup: cannot fixup past commit; working directory must be clean."
sys.exit(5)
call([git, "commit", "--fixup=" + broken_commit])
call(["set", "GIT_EDITOR=true", "&&", git, "rebase", "-i", "--autosquash", broken_commit + "~1"], shell=True)