git: add hook prepare-commit-msg

1 files changed, 45 insertions, 0 deletions

diff --git a/.githooks/prepare-commit-msg b/.githooks/prepare-commit-msg
new file mode 100755
index 0000000000..44ae86d26a
--- /dev/null
+++ b/.githooks/prepare-commit-msg
@@ -0,0 +1,45 @@
+#!/bin/sh
+#
+# This hook adds prefix "<repo>/<pkgname>: " to the commit message when
+# committing changes of a single package.
+#
+MSG_FILE="$1"
+SOURCE="$2"
+
+longest_common_prefix() {
+        awk -F/ '
+                (NR == 1) { split($0, prefix); prefix_len = NF }
+                (NR > 1) {
+                        for (i = 1; i <= prefix_len; i++) {
+                                if (prefix[i] != $i) {
+                                        prefix_len = i - 1; break
+                                }
+                        }
+                }
+                (prefix_len == 0) { exit }
+                END {
+                        res = prefix[1]
+                        for (i = 2; i <= prefix_len; i++) {
+                                res = res FS prefix[i]
+                        }
+                        print(res)
+                }'
+}
+
+prepend_msg() {
+        local prefix="$1"
+
+        printf '%s\n%s\n' "$prefix" "$(cat "$MSG_FILE")" > "$MSG_FILE"
+}
+
+
+# Do nothing if message has been given using -m, template, merge etc.
+[ -z "$SOURCE" ] || exit 0
+
+lcp=$(git diff-index --name-only --cached HEAD | longest_common_prefix)
+
+case "$lcp" in
+        [^.]*/*) prepend_msg "$(echo "$lcp" | cut -d/ -f1-2): ";;
+esac
+
+exit 0