From afb733f02a37072b7e337fad86acbba14d584e60 Mon Sep 17 00:00:00 2001
From: Richard Smith <richard@metafoo.co.uk>
Date: Wed, 22 Apr 2026 18:58:36 -0700
Subject: [PATCH] Don't allow merging PRs with the `dependent` label. (#7096)

This should reduce the chance of a dependent PR being merged before its
base PR is merged.

Assisted-by: Gemini via Antigravity
---
 .github/workflows/check_dependent.yaml | 29 ++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)
 create mode 100644 .github/workflows/check_dependent.yaml

diff --git a/.github/workflows/check_dependent.yaml b/.github/workflows/check_dependent.yaml
new file mode 100644
index 000000000000..220a1da286bf
--- /dev/null
+++ b/.github/workflows/check_dependent.yaml
@@ -0,0 +1,29 @@
+# Part of the Carbon Language project, under the Apache License v2.0 with LLVM
+# Exceptions. See /LICENSE for license information.
+# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+name: Check Dependent Label
+on:
+  pull_request_target:
+    types: [opened, synchronize, labeled, unlabeled]
+
+jobs:
+  check_label:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Harden Runner
+        uses: step-security/harden-runner@58077d3c7e43986b6b15fba718e8ea69e387dfcc # v2.15.1
+        with:
+          disable-sudo: true
+          egress-policy: block
+          # prettier-ignore
+          allowed-endpoints: >
+            api.github.com:443
+
+      - name: Check for 'dependent' label
+        run: |
+          if [[ "${{ contains(github.event.pull_request.labels.*.name, 'dependent') }}" == "true" ]]; then
+            echo "PR has 'dependent' label. Blocking merge."
+            exit 1
+          fi
+          echo "PR does not have 'dependent' label."