From 8427fa1a0db04768205086ee1d6fdbd48996c533 Mon Sep 17 00:00:00 2001
From: Lloyd Evans <contact@lloydevans.co.uk>
Date: Thu, 8 Oct 2026 20:59:48 +0100
Subject: [PATCH] Trigger push workflows on main and name the branch nowhere
 else

The mutation workflow's concurrency group and tip check use the pushed ref, and its comment, its step id and the README say "default branch".
---
 .github/workflows/ci.yml       |  2 +-
 .github/workflows/mutation.yml | 12 ++++++------
 README.md                      |  2 +-
 3 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 5aa7082..cb92ce2 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -2,7 +2,7 @@ name: CI
 
 on:
   push:
-    branches: [master]
+    branches: [main]
   pull_request:
 
 permissions:
diff --git a/.github/workflows/mutation.yml b/.github/workflows/mutation.yml
index f329da3..0546d79 100644
--- a/.github/workflows/mutation.yml
+++ b/.github/workflows/mutation.yml
@@ -2,7 +2,7 @@ name: Mutation
 
 on:
   push:
-    branches: [master]
+    branches: [main]
   pull_request:
     types: [opened, ready_for_review, synchronize, reopened]
   workflow_dispatch:
@@ -11,7 +11,7 @@ permissions:
   contents: read
 
 concurrency:
-  group: ${{ github.workflow }}-${{ github.event_name }}-${{ github.event.pull_request.number || (github.event_name == 'push' && 'master') || github.run_id }}
+  group: ${{ github.workflow }}-${{ github.event_name }}-${{ github.event.pull_request.number || (github.event_name == 'push' && github.ref) || github.run_id }}
   cancel-in-progress: ${{ github.event_name == 'pull_request' }}
 
 jobs:
@@ -37,20 +37,20 @@ jobs:
       - name: Rebuild mutation results
         if: github.event_name == 'push'
         run: npm run mutation -- --force
-      # Runs on master go one at a time and only the tip saves, so an older run cannot replace newer results.
+      # Runs on the default branch go one at a time and only the tip saves, so an older run cannot replace newer results.
       - name: Check baseline revision
-        id: master-tip
+        id: default-branch-tip
         if: ${{ !cancelled() && github.event_name == 'push' && hashFiles('reports/stryker-incremental.json') != '' }}
         shell: bash
         run: |
-          tip=$(git ls-remote --exit-code origin refs/heads/master)
+          tip=$(git ls-remote --exit-code origin "$GITHUB_REF")
           if [[ "${tip%%$'\t'*}" == "$GITHUB_SHA" ]]; then
             echo "current=true" >> "$GITHUB_OUTPUT"
           else
             echo "current=false" >> "$GITHUB_OUTPUT"
           fi
       - uses: actions/cache/save@v6
-        if: ${{ !cancelled() && steps.master-tip.outputs.current == 'true' }}
+        if: ${{ !cancelled() && steps.default-branch-tip.outputs.current == 'true' }}
         with:
           path: reports/stryker-incremental.json
           key: mutation-${{ runner.os }}-${{ github.run_id }}-${{ github.run_attempt }}
diff --git a/README.md b/README.md
index 15b3ec6..6b301b5 100644
--- a/README.md
+++ b/README.md
@@ -32,4 +32,4 @@ Run `npm install` at the root to install dependencies and link the packages decl
 - [index.html](index.html) is the entry page. Vite uses its defaults without a configuration file, including its browser target and no production source maps.
 - Vite transpiles TypeScript without type-checking. Run `npm run typecheck` to check types; `npm run verify-gate` includes it before the tests and build.
 - TypeScript is pinned to the 6.x line.
-- Mutation testing uses [Stryker's incremental mode](https://stryker-mutator.io/docs/stryker-js/incremental/). Changes outside mutated source and test files can leave reused results stale; run `npm run mutation -- --force` for a fresh full run. CI does this on pushes to `master`.
+- Mutation testing uses [Stryker's incremental mode](https://stryker-mutator.io/docs/stryker-js/incremental/). Changes outside mutated source and test files can leave reused results stale; run `npm run mutation -- --force` for a fresh full run. CI does this on pushes to the default branch.