From 667c3d2541a511502747ba80f039db76a12e6a23 Mon Sep 17 00:00:00 2001
From: MaxMustermann2 <82761650+MaxMustermann2@users.noreply.github.com>
Date: Mon, 4 Mar 2024 09:05:02 +0000
Subject: [PATCH] doc(ci): add comment to explain HEAD~1

---
 .github/workflows/proto.yml | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/.github/workflows/proto.yml b/.github/workflows/proto.yml
index 75e72fb35..d450c6f3a 100644
--- a/.github/workflows/proto.yml
+++ b/.github/workflows/proto.yml
@@ -41,4 +41,8 @@ jobs:
       - uses: bufbuild/buf-breaking-action@v1
         with:
           input: "proto"
+          # previously, this ran on ref=HEAD~1, which is incorrect as it can
+          # only be used to compare within a branch. it is designed to run
+          # on a PR, so it must compare the HEAD of the base branch against
+          # the PR branch.
           against: "https://github.com/${{ github.repository }}.git#branch=${{ github.event.pull_request.base.ref }},subdir=proto"