ci: bidirectional mirror between GitHub and Gitea

scripts/mirror.sh

@@ -0,0 +1,22 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+BRANCH="${BRANCH:-main}"
+
+git config user.name  "mirror-bot"
+git config user.email "mirror-bot@noreply.local"
+
+git remote remove mirror 2>/dev/null || true
+git remote add mirror "$MIRROR_URL"
+
+git fetch origin "$BRANCH"
+git fetch mirror "$BRANCH"
+
+if git rev-parse --verify -q "mirror/$BRANCH" >/dev/null; then
+  if ! git merge-base --is-ancestor "mirror/$BRANCH" HEAD; then
+    git merge --no-edit "mirror/$BRANCH"
+  fi
+fi
+
+git push origin "HEAD:$BRANCH"
+git push mirror "HEAD:$BRANCH"