Git hook to prevent unformatted code from being committed

.gitignore

@@ -150,6 +150,9 @@ src/config
 # codespell dictionary
 scripts/dictionary/
 
+# marker files for pre-commit and pre-push hooks to check if staged files have been formatted
+scripts/.format_markers/
+
 # clangd for nvim lsp
 src/.clangd
 

environment_setup/setup_software.sh

@@ -18,6 +18,8 @@
 CURR_DIR=$(dirname -- "$(readlink -f -- "$BASH_SOURCE")")
 cd "$CURR_DIR" || exit
 
+git config core.hooksPath "$CURR_DIR/../scripts/githooks"
+
 source util.sh
 
 g_arch=$(uname -m)  # Global variable. No function should use this name.

scripts/githooks/pre-commit

@@ -0,0 +1,19 @@
+#!/bin/sh
+
+filter_formattable_files() {
+    grep -E '\.(h|cpp|c|cc|hpp|tpp|proto|py|md|yml)$|/BUILD$'
+}
+
+toplevel="$(git rev-parse --show-toplevel)"
+marker="$toplevel/scripts/.format_markers/$(git rev-parse --abbrev-ref HEAD)"
+mtime=$(stat -c %Y "$marker" 2> /dev/null || echo 0)
+
+git diff --staged --name-only | filter_formattable_files | while read -r file; do
+    if [ $mtime -lt "$(stat -c %Y "$toplevel/$file")" ]; then
+        # The file was modified AFTER formatting. Remove the marker to tell the pre-push hook
+        # that this commit introduces unformatted code.
+        rm -f "$marker" 2> /dev/null
+        echo "Warning: Code is unformatted."
+        break
+    fi
+done

scripts/githooks/pre-push

@@ -0,0 +1,28 @@
+#!/usr/bin/env bash
+
+confirm() {
+    read -r -p "$1 [y/N] " response < /dev/tty
+    case "$response" in
+        [yY][eE][sS]|[yY])
+            return 0
+            ;;
+        *)
+            return 1
+            ;;
+    esac
+}
+
+scriptsdir="$(git rev-parse --show-toplevel)/scripts"
+
+if ! [ -f "$scriptsdir/.format_markers/$(git rev-parse --abbrev-ref HEAD)" ]; then
+    echo "Warning: Code is unformatted. Please run $scriptsdir/lint_and_format.sh."
+    if confirm 'Continue without formatting?'; then
+        echo "Continuing push anyway."
+        exit 0
+    else
+        echo "Aborting push."
+        exit 1
+    fi
+fi
+
+# vim:ts=4 et

scripts/lint_and_format.sh

@@ -149,4 +149,10 @@ run_eof_new_line
 run_git_diff_check
 run_ansible_lint
 
+# Update markers, telling Git hooks that formatting has been done
+# (Per-branch, so switching branches doesn't confuse the hooks)
+branch="$(git rev-parse --abbrev-ref HEAD)"
+mkdir -p "$CURR_DIR/.format_markers/$(dirname "$branch")"
+touch "$CURR_DIR/.format_markers/${branch}"
+
 exit 0