From 735a11c84917eba85c502700ab0d69bb36703825 Mon Sep 17 00:00:00 2001
From: Claude <noreply@anthropic.com>
Date: Fri, 1 May 2026 07:16:42 +0000
Subject: [PATCH] Add PR preview environments via GitHub Actions

Switch production deployment from artifact-based Pages to a gh-pages
branch (peaceiris/actions-gh-pages), enabling PR previews to coexist
as subdirectories alongside the live site.

Add preview.yml: on every PR open/sync/reopen, builds Hugo with a
PR-specific baseURL and deploys to pr-preview/pr-{number}/ on the
gh-pages branch via rossjrw/pr-preview-action. The action posts a
comment on the PR with the live preview URL and cleans up the
subdirectory automatically when the PR is closed.

https://claude.ai/code/session_01MA7Ekd1KB4MpXrC6aUeivs
---
 .github/workflows/deploy.yml  | 27 +++++++----------------
 .github/workflows/preview.yml | 40 +++++++++++++++++++++++++++++++++++
 2 files changed, 48 insertions(+), 19 deletions(-)
 create mode 100644 .github/workflows/preview.yml

diff --git a/.github/workflows/deploy.yml b/.github/workflows/deploy.yml
index 7af4531..b6901c3 100644
--- a/.github/workflows/deploy.yml
+++ b/.github/workflows/deploy.yml
@@ -7,11 +7,9 @@ on:
     branches: [main]
   workflow_dispatch:
 
-# Allow the workflow to write to GitHub Pages
+# Write access to push the built site to the gh-pages branch
 permissions:
-  contents: read
-  pages: write
-  id-token: write
+  contents: write
 
 # Only allow one deployment at a time; don't cancel in-progress runs
 concurrency:
@@ -19,7 +17,7 @@ concurrency:
   cancel-in-progress: false
 
 jobs:
-  build:
+  build-and-deploy:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v7
@@ -41,18 +39,9 @@ jobs:
         # hugo.toml sets minifyOutput = false because Hugo's minifier
         # breaks PaperMod's JSON-LD schema output.
 
-      - name: Upload Pages artifact
-        uses: actions/upload-pages-artifact@v5
+      - name: Deploy to gh-pages branch
+        uses: peaceiris/actions-gh-pages@v4
         with:
-          path: site/public
-
-  deploy:
-    needs: build
-    runs-on: ubuntu-latest
-    environment:
-      name: github-pages
-      url: ${{ steps.deployment.outputs.page_url }}
-    steps:
-      - name: Deploy to GitHub Pages
-        id: deployment
-        uses: actions/deploy-pages@v5
+          github_token: ${{ secrets.GITHUB_TOKEN }}
+          publish_dir: site/public
+          publish_branch: gh-pages
diff --git a/.github/workflows/preview.yml b/.github/workflows/preview.yml
new file mode 100644
index 0000000..35223d8
--- /dev/null
+++ b/.github/workflows/preview.yml
@@ -0,0 +1,40 @@
+name: PR Preview
+
+on:
+  pull_request:
+    types: [opened, synchronize, reopened, closed]
+
+# Write to gh-pages branch and post comments on the PR
+permissions:
+  contents: write
+  pull-requests: write
+
+jobs:
+  preview:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v7
+        with:
+          submodules: recursive
+          fetch-depth: 0
+
+      - name: Setup Hugo
+        if: github.event.action != 'closed'
+        uses: peaceiris/actions-hugo@v3
+        with:
+          hugo-version: '0.155.3'
+          extended: true
+
+      - name: Build preview
+        if: github.event.action != 'closed'
+        # -D includes drafts so in-progress posts are visible in the preview
+        run: hugo --source site --baseURL "https://mathieson.github.io/blog/pr-preview/pr-${{ github.event.number }}/" -D
+
+      - name: Deploy / remove preview
+        uses: rossjrw/pr-preview-action@v1
+        with:
+          source-dir: site/public
+          preview-branch: gh-pages
+          umbrella-dir: pr-preview
+          action: auto
+          token: ${{ secrets.GITHUB_TOKEN }}