#!/bin/sh

# Auto-tidy staged Perl before it lands.
#
# A file qualifies three ways:
#   - a .pm, .pl or .t extension
#   - a .PL extension, which is how Makefile.PL gets covered
#   - executable with perl on its shebang line, which is how the extensionless
#     scripts in bin/ get covered
#
# .t is in there because only one of the seven test files happens to be +x,
# so the shebang rule alone would have tidied that one and let the rest drift.

# Redirect output to stderr.
exec 1>&2

if ! command -v perltidy >/dev/null 2>&1
then
    echo "pre-commit: perltidy is not on PATH, skipping the tidy pass."
    exit 0
fi

# ACMR so that a file deleted in this commit is not handed to perltidy, which
# would fail on a path that is no longer there.
staged=$(git diff --cached --name-only --diff-filter=ACMR)

to_tidy=''
for file in $staged
do
    test -f "$file" || continue

    case "$file" in
        *.pm|*.pl|*.PL|*.t)
            to_tidy="$to_tidy $file"
            continue
            ;;
    esac

    if test -x "$file" && head -n 1 "$file" | grep -Eq '^#!.*perl'
    then
        to_tidy="$to_tidy $file"
    fi
done

# -n and quoted, unlike the version this replaces: bare [ $to_tidy ] is a
# syntax error the moment there is more than one file, so the hook quietly
# stopped tidying in exactly the commits that needed it most.
if [ -n "$to_tidy" ]
then
    echo "Auto-tidying perl changes..."

    # -bext='/' makes perltidy delete the backup it would otherwise leave
    # sitting next to the file as <name>.bak.
    perltidy -b -bext='/' $to_tidy || {
        echo "pre-commit: perltidy failed, leaving the commit alone."
        exit 1
    }

    git update-index --add $to_tidy
    echo "Done."
fi