test: let print workflows own their worktrees

.gitea/workflows/print2.yml

@@ -24,7 +24,9 @@ jobs:
 
           REPO_NAME="${{ github.event.repository.name }}"
           HEAD_SHA="${{ github.event.workflow_run.head_sha }}"
+          REPOSITORY_DIR="${WORKSPACE_ROOT}/${REPO_NAME}/repository.git"
           WORKTREE_DIR="${WORKSPACE_ROOT}/${REPO_NAME}/worktrees/print2"
+          WORKTREE_LOCK="${WORKSPACE_ROOT}/${REPO_NAME}/worktree-admin.lock"
 
           case "$HEAD_SHA" in
             ''|*[!0-9a-fA-F]*)
@@ -32,12 +34,43 @@ jobs:
               exit 1
               ;;
           esac
-          if [ ! -f "$WORKTREE_DIR/.git" ]; then
-            echo "Prepare 未创建 Print Two Worktree: $WORKTREE_DIR" >&2
+
+          if [ ! -d "$REPOSITORY_DIR" ] || \
+             [ "$(git --git-dir="$REPOSITORY_DIR" rev-parse --is-bare-repository)" != "true" ]; then
+            echo "Prepare 未创建共享 bare 仓库: $REPOSITORY_DIR" >&2
             exit 1
           fi
-          if ! git -C "$WORKTREE_DIR" cat-file -e "${HEAD_SHA}^{commit}"; then
-            echo "Worktree 共享仓库中不存在上游提交: $HEAD_SHA" >&2
+          if ! git --git-dir="$REPOSITORY_DIR" cat-file -e "${HEAD_SHA}^{commit}"; then
+            echo "共享仓库中不存在上游提交: $HEAD_SHA" >&2
+            exit 1
+          fi
+
+          if [ ! -f "$WORKTREE_DIR/.git" ]; then
+            if ! command -v flock >/dev/null 2>&1; then
+              echo "首次创建 Worktree 需要 flock" >&2
+              exit 1
+            fi
+
+            exec 9>"$WORKTREE_LOCK"
+            flock 9
+
+            if [ ! -f "$WORKTREE_DIR/.git" ]; then
+              if [ -e "$WORKTREE_DIR" ]; then
+                echo "Worktree 路径已存在但不是 linked worktree: $WORKTREE_DIR" >&2
+                exit 1
+              fi
+
+              mkdir -p "$(dirname "$WORKTREE_DIR")"
+              echo "首次创建 Print Two Worktree: $WORKTREE_DIR"
+              git --git-dir="$REPOSITORY_DIR" worktree add --detach "$WORKTREE_DIR" "$HEAD_SHA"
+            fi
+
+            flock -u 9
+          fi
+
+          COMMON_DIR=$(git -C "$WORKTREE_DIR" rev-parse --path-format=absolute --git-common-dir)
+          if [ "$COMMON_DIR" != "$(realpath "$REPOSITORY_DIR")" ]; then
+            echo "Print Two Worktree 不属于共享仓库: $WORKTREE_DIR" >&2
             exit 1
           fi