format

1#!/usr/bin/env bash
2# Format staged source files with the standard formatter for each language.
3set -euo pipefail
4
5root=$(git rev-parse --show-toplevel)
6cd "$root"
7
8# Read staged paths safely, including paths containing whitespace.
9mapfile -d '' files < <(git diff --cached --name-only --diff-filter=ACMR -z)
10((${#files[@]})) || exit 0
11
12format() {
13    local tool=$1
14    shift
15    command -v "$tool" >/dev/null 2>&1 || {
16        printf 'format: required formatter not found: %s\n' "$tool" >&2
17        exit 1
18    }
19    "$tool" "$@"
20}
21
22java=() c=() cpp=() go=() python=() js=() web=()
23for file in "${files[@]}"; do
24    case "$file" in
25        *.java) java+=("$file") ;;
26        *.c|*.h) c+=("$file") ;;
27        *.cc|*.cpp|*.cxx|*.hpp|*.hh|*.hxx) cpp+=("$file") ;;
28        *.go) go+=("$file") ;;
29        *.py) python+=("$file") ;;
30        *.js|*.jsx|*.ts|*.tsx|*.json|*.css|*.html|*.md|*.yaml|*.yml) web+=("$file") ;;
31    esac
32done
33
34((${#java[@]} == 0)) || format google-java-format --replace "${java[@]}"
35((${#c[@]} == 0)) || format clang-format -i "${c[@]}"
36((${#cpp[@]} == 0)) || format clang-format -i "${cpp[@]}"
37((${#go[@]} == 0)) || format gofmt -w "${go[@]}"
38((${#python[@]} == 0)) || format black "${python[@]}"
39((${#web[@]} == 0)) || format prettier --write "${web[@]}"
40
41# Include formatter output in the commit; never silently leave unstaged formatting.
42git add -- "${files[@]}"