git: make prune-local also remove branches by other users

.config/git/config

@@ -39,4 +39,3 @@
 	ff-head = "!git push . origin/HEAD:$(git head)"
 	head = for-each-ref --format="%(symref:lstrip=-1)" refs/remotes/origin/HEAD
 	sh = "!git switch $(git head)"
-	prune-local = "!git branch --merged origin/HEAD | grep -v $(git head) | xargs git branch -d"

.local/bin/git-prune-local

@@ -0,0 +1,22 @@
+#!/usr/bin/env bash
+
+set -euo pipefail
+
+self=$(git config --get user.name)
+head=$(git head)
+
+for branch in $(git for-each-ref --format='%(refname:short)' refs/heads/); do
+  if [ "$branch" == "$head" ]; then
+    continue
+  fi
+
+  if git merge-base --is-ancestor "$branch" origin/HEAD; then
+    git branch -d "$branch"
+    continue
+  fi
+
+  author=$(git show --no-patch --pretty='%an' "$branch")
+  if [ "$author" != "$self" ]; then
+    git branch -D "$branch"
+  fi
+done