Question

I’m trying to use a Git pre-commit hook to run some style checks and automatically generate an AUTHORS file that pulls in the names of all contributors using git shortlog.

My pre-commit script consists of the following:

#!/bin/sh
set -e

bin/update-authors.sh
...

The update-authors.sh file consists of the following:

#!/bin/sh
set -e

# Get a list of authors ordered by number of commits
# and remove the commit count column
AUTHORS=$(git --no-pager shortlog -nse | cut -f 2-)
if [ -z "$AUTHORS" ] ; then
    echo "Authors list was empty"
    exit 1
fi

# Display the authors list and write it to the file
echo "$AUTHORS" | tee "$(git rev-parse --show-toplevel)/AUTHORS"

The latter script works fine directly from a terminal, but only during the pre-commit hook, it errors out with “Authors list was empty”. I can’t figure out why it’s doing this – any ideas?

Answer 1

I think that when performing pre-commit hook, git keeps tree in semi-detached state, and that’s why it doesn’t get anything. As seen in the example pre-commit hook, you need to pass some branch/commit explicitly, e.g.:

AUTHORS=$(git --no-pager shortlog -nse HEAD | cut -f 2-)