pre-commit hook to prevent committing unwanted changes

pre-commit

#!/bin/sh

# Reject commits on some stop words:
#  nocommit: include this word (in a comment) when you're doing a local change that should not be committed
#  fdescribe: used in jasmine to run a single test
#
# Usage: save in .git/hooks/pre-commit of a given repository, and make executable

declare -a stopwords=("nocommit" "fdescribe")

if git rev-parse --verify HEAD >/dev/null 2>&1
then
    against=HEAD
else
    # Initial commit: diff against an empty tree object
    against=$(git hash-object -t tree /dev/null)
fi

patch_filename=$(mktemp -t commit_hook_changes.XXXXXX)
git diff --exit-code --binary --ignore-submodules --no-color > $patch_filename
has_unstaged_changes=$?

if [ $has_unstaged_changes -ne 0 ]; then
    echo "Stashing unstaged changes in $patch_filename."
    git checkout -- .
fi

quit() {
    if [ $has_unstaged_changes -ne 0 ]; then
        git apply $patch_filename
        if [ $? -ne 0 ]; then
            git checkout -- .
            git apply $patch_filename
        fi
    fi

    exit $1
}

# Redirect output to stderr.
exec 1>&2

for word in "${stopwords[@]}"
do
    files_with_word=$(git diff --cached --name-only --diff-filter=ACM $against | xargs grep -i "$word" -l | tr '\n' ' ')

    if [ "x${files_with_word}x" != "xx" ]; then
        tput setaf 1
        echo "File being committed with '$word' in it:"
        echo $files_with_word | tr ' ' '\n'
        tput sgr0
        quit 1
    fi
done

quit 0