How do I check for valid Git branch names?

Question

I\'m developing a git post-receive hook in Python. Data is supplied on stdin with lines similar to

ef4d4037f8568e386629457d4d960915a85da2ae 61a4         


        

Answer 1

git check-ref-format with subprocess.Popen is a possibility:

import subprocess
process = subprocess.Popen(["git", "check-ref-format", ref])
exit_status = process.wait()

Advantages:

• if the algorithm ever changes, the check will update automatically
• you are sure to get it right, which is way harder with a monster Regex

Disadvantages:

• slower because subprocess. But premature optimization is the root of all evil.
• requires Git as a binary dependency. But in the case of a hook it will always be there.

pygit2, which uses C bindings to libgit2, would be an even better possibility if check-ref-format is exposed there, as it would be faster than Popen, but I haven't found it.