From b88347fd709866d51eb808cea2f777de0525f80e Mon Sep 17 00:00:00 2001
From: Jake Lee Kennedy <1731150+Jakeii@users.noreply.github.com>
Date: Tue, 28 Jul 2026 12:24:45 +0100
Subject: [PATCH] update chromatic ref for merge_queue

---
 .github/workflows/dcr-chromatic.yml | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/.github/workflows/dcr-chromatic.yml b/.github/workflows/dcr-chromatic.yml
index 5516bcf2c4d..94ddb34d442 100644
--- a/.github/workflows/dcr-chromatic.yml
+++ b/.github/workflows/dcr-chromatic.yml
@@ -28,7 +28,9 @@ jobs:
           # By default the pull_request event will run on a ephermeral merge commit which simulates a merge between the pull request
           # and the target branch. This can cause issues with Chromatic https://www.chromatic.com/docs/turbosnap#github-pullrequest-triggers
           # Hopefully by checking out the HEAD commit of a PR instead of the merge commit we can avoid some of those issues.
-          ref: ${{ github.event.pull_request.head.sha }}
+          # We fallback to github.sha in case the workflow is triggered by a merge_group event, which doesn't have a pull_request object, see https://www.chromatic.com/docs/faq/merge-queue-ref/
+          ref: ${{ github.event.pull_request.head.ref || github.sha }}
+
       - name: Checkout - On Push Event
         uses: actions/checkout@v6
         if: ${{ github.event_name == 'push' || github.event_name == 'merge_group' }}