CODEWITHSUNDEEP
pythongitoperating-system
Gabriel
Gabriel

Reputation: 42389

Check latest commit with Python in Linux/Windows/Mac

I'm trying to generate a simple Python code that:

  1. checks if it is running inside a git folder
  2. if so, fetch the latest commit, else skip
  3. it should work under the three platforms: Linux, Windows, and Mac

I have this code that works correctly under Linux:

from subprocess import call, STDOUT
import os

if call(["git", "branch"], stderr=STDOUT, stdout=open(os.devnull, 'w')) != 0:
    # Not a git folder
    commit = ''
else:
    # Inside a git folder.: fetch latest commit
    commit = subprocess.check_output(['git', 'rev-parse', '{}'.format('HEAD')])

print(commit)

but I have no way of checking if itwill work under Windows and Mac.

Does it work? Is there any way of checking/knowing this sort of things when one has no access to the other operating system?

Upvotes: 0

Views: 93

Answers (2)

cosmicsage
cosmicsage

Reputation: 155

There's a method check_output in subprocess library

from subprocess import check_output
try:
    # use python to parse this log for info. This is your entire last commit
    logs = check_output(['git', 'log', '-1', '--stat']).decode("UTF-8")
except Exception as e:
    # Do whatever you wanna do otherwise if not git repository
    print(e)

Git has a command called "git log".

"-1" indicates the last commit and --stat will give you the files that were changed, commit ID, TIME ETC

then you can use python to parse this log and retrive any information you want Check this out for more info on git log

Upvotes: 1

bk2204
bk2204

Reputation: 76774

You don't want to run git branch to detect whether you're in a Git repository, because you may or may not have any branches. To detect whether you're able to use Git commands, you'll want to run something like git rev-parse --git-dir, which will exit non-zero if you're not within a Git repository.

However, there are a couple of other issues with your code. First of all, in a new repository (one created fresh with git init), there will be a .git directory and the above command will succeed, but HEAD will not point anywhere. Therefore, your git rev-parse HEAD command will fail and print HEAD and an error.

Finally, if you want parse a revision, you should usually use --verify so that you don't print the dummy HEAD value on failure. So your invocation should look like git rev-parse --verify HEAD.

Ultimately, it's up to you to figure out what you want to do in a newly initialized repository, whether that's fail or fall back to an empty string.

The behaviors I've described here are consistent across platforms; they're built into Git and well defined.

Upvotes: 2

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