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Git Pre-commit Hook For Python now with extra Python!
#!/usr/bin/env python
#-*- mode: python -*-
from subprocess import Popen, PIPE
import sys
syntax_checker = "pyflakes"
def run(command):
p = Popen(command.split(), stdout=PIPE, stderr=PIPE)
p.wait()
return p.returncode, p.stdout.read().strip().split(), p.stderr.read()
_, files_modified, _= run("git diff-index --name-only --cached HEAD")
for fname in files_modified:
if fname.endswith(".py"):
print >>sys.stderr, "Checking syntax on %s: ... "%(fname,),
exit_code, _, errors = run("%s %s"%(syntax_checker, fname))
if exit_code != 0:
print >>sys.stderr, "\rChecking syntax on %s: FAILED! \n%s"%(fname, errors)
sys.exit(exit_code)
else:
print >>sys.stderr, "\rChecking syntax on %s: OK!"%(fname,)

Ceasar commented Nov 29, 2011

On line 12, why do you strip and split p.stdout exactly? (I notice when reverting this, the precommit hooks fails.)

Owner

steder commented Nov 29, 2011

Because run is first called with a 'git diff-index' and in that case the p.stdout.read().strip().split() is a list of filenames. Of course you're right, in the pyflakes case the strip() and split() on the output is unnecessary. This would probably be easier to understand if there was a separate function for getting the list of modified file names.

Ceasar commented Nov 29, 2011

Ah- Somehow I had completely missed line 14. Much easier to understand the control-flow now.

mtigas commented Jul 18, 2012

Helpful modification I've been using:

L14 should probably be

_, files_modified, _= run("git diff-index --name-only --cached HEAD")

so that non-staged files are ignored. i.e. we only run pyflakes against the files we're trying to commit, not the entire source tree.

Owner

steder commented Jul 18, 2012

Thanks @mtigas, I've updated the gist.

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