pre-commit

#!/bin/bash

# Git pre-commit hook applying Ktlint on staged files
# (using user-defined gradle task)


STASH_NAME=pre-commit-$(date +%s)-$RANDOM
if ! git diff-files --quiet ; then
    # dirty workdir: stash to work on staged files only
    git stash push -q --keep-index -m "$STASH_NAME"
fi

echo "Pre-commit hook: Running ktlint (fix)"
gradle ktlintFix
RESULT=$?
# stage modified files
git add --update

# restore workdir
# get stash ID (stash{#}) (empty if workdir was clean)
STASH_ID=$(git stash list | sed -En "s/(stash@\{.*\}).*$STASH_NAME.*/\1/p")

if [[ -n "$STASH_ID" ]] ; then
    # git stash pop would conflict with changes kept in index
    # in partially added files : use diff/apply.
    git diff $STASH_ID^2 $STASH_ID | git apply
    if [ $? -eq 0 ] ; then
        git stash drop -q $STASH_ID
    else
        echo "Pre-commit hook did conflicting changes (see previous messages)"
        echo "Previous workdir state is stashed in $STASH_ID: $STASH_NAME"
    fi
fi

exit $RESULT