From baced6e20ff2bc290e257315df6cbcd9c7767193 Mon Sep 17 00:00:00 2001
From: Michael Taylor <michael@michaeltaylor.dev>
Date: Sun, 13 Sep 2026 18:27:39 -0700
Subject: [PATCH] ci: propagate main's release-cut commitlint depth to develop

On a `pull_request` event GitHub runs the workflow definition from the
PR's HEAD branch, not its base. A `develop -> main` release PR therefore
executes develop's copy of `.github/workflows/commitlint.yml`, and main's
copy is never consulted. Develop's copy lints the entire inherited
`main..develop` range, so a release cut fails on immutable historical
commit messages that were written long before the current PR.

Main already carries the fix: a `commitDepth: 1` job gated on
`github.base_ref == 'main'` for release cuts, the full-range job gated on
`!= 'main'` for feature branches, and a PR-title lint that appends
`(#PR_NUMBER)` before linting. Because the release-cut branch of that fix
only ever runs from the HEAD branch of a cut, and cuts run from develop,
it has never once applied to a cut.

The file never reached develop because the `-s ours` reconciliation at
cd8ce7b8 records ancestry without bringing any content across. This
commit takes main's version verbatim -- it is already reviewed and
already required-green on main.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
---
 .github/workflows/commitlint.yml | 21 +++++++++++++++++++--
 1 file changed, 19 insertions(+), 2 deletions(-)

diff --git a/.github/workflows/commitlint.yml b/.github/workflows/commitlint.yml
index 9f1d6884..2d0588a7 100644
--- a/.github/workflows/commitlint.yml
+++ b/.github/workflows/commitlint.yml
@@ -28,7 +28,20 @@ jobs:
         with:
           fetch-depth: 0
 
-      - name: Lint PR commits
+      # A main-base PR is a develop -> main release cut: every commit in main..develop
+      # was already linted at its own PR, while that commit was still mutable and its
+      # author could still fix it. Re-linting the whole inherited range at cut time adds
+      # no information and cannot be satisfied (the commits are now immutable, pinned by
+      # gitlinks and rev-pinned deps). Lint only what THIS PR introduces: its own commit(s).
+      - name: Lint PR commits (release cut — this PR's own commits only)
+        if: github.base_ref == 'main'
+        uses: wagoid/commitlint-github-action@v6
+        with:
+          configFile: commitlint.config.mjs
+          commitDepth: 1
+
+      - name: Lint PR commits (feature branch — full PR range)
+        if: github.base_ref != 'main'
         uses: wagoid/commitlint-github-action@v6
         with:
           configFile: commitlint.config.mjs
@@ -37,9 +50,13 @@ jobs:
         if: github.event_name == 'pull_request'
         env:
           PR_TITLE: ${{ github.event.pull_request.title }}
+          PR_NUMBER: ${{ github.event.pull_request.number }}
         run: |
           set -euo pipefail
           # Install both @commitlint/cli AND the extended shareable config so the
           # `extends: ['@commitlint/config-conventional']` in commitlint.config.mjs resolves.
-          echo "$PR_TITLE" | npx --yes -p @commitlint/cli -p @commitlint/config-conventional \
+          # GitHub's squash merge lands "$PR_TITLE (#$PR_NUMBER)" as the commit subject —
+          # lint that exact string, not the title alone, or a title within the length
+          # limit can still produce an over-limit commit subject once merged.
+          printf '%s (#%s)\n' "$PR_TITLE" "$PR_NUMBER" | npx --yes -p @commitlint/cli -p @commitlint/config-conventional \
             commitlint --config commitlint.config.mjs