Support build-website PR label

.github/workflows/pkgdown.yaml

@@ -1,10 +1,12 @@
 # Workflow derived from https://github.com/r-lib/actions/tree/v2/examples
 # Need help debugging build failures? Start at https://github.com/r-lib/actions#where-to-find-help
 on:
+  # build dev site on merged pushes
   push:
     branches: [main, master]
   pull_request:
-    types: [opened, reopened, synchronize, labeled]
+    types: [opened, reopened, synchronize, labeled, closed]
+  # build full site on releases
   release:
     types: [published]
   workflow_dispatch:
@@ -16,14 +18,18 @@ jobs:
     # For PRs, only run when the PR has the build-website label.
     if: >-
       github.event_name != 'pull_request' ||
-      contains(github.event.pull_request.labels.*.name, 'build-website')
+      (
+        github.event.action != 'closed' &&
+        contains(github.event.pull_request.labels.*.name, 'build-website') &&
+        (github.event.action != 'labeled' || github.event.label.name == 'build-website')
+      )
     runs-on: ubuntu-latest
-    # Only restrict concurrency for non-PR jobs
     concurrency:
       group: pkgdown-${{ github.event_name == 'pull_request' && github.event.pull_request.number || 'production' }}
       cancel-in-progress: true
     env:
       GITHUB_PAT: ${{ secrets.GITHUB_TOKEN }}
+      NOT_CRAN: "true"
     permissions:
       contents: write
     steps:
@@ -34,24 +40,40 @@ jobs:
       - uses: r-lib/actions/setup-r@v2
         with:
           use-public-rspm: true
-          extra-repositories: https://stan-dev.r-universe.dev
 
       - uses: r-lib/actions/setup-r-dependencies@v2
         with:
-          extra-packages: any::pkgdown, local::.
-          needs: website
+          extra-packages: any::pkgdown, local::., stan-dev/pkgdown-config
 
       - name: Build site
-        id: pkgdown
+        env:
+          PR_NUMBER: ${{ github.event.pull_request.number }}
         run: |
-          pkgdown::build_site_github_pages(clean = FALSE, new_process = TRUE, install = FALSE)
-        shell: Rscript {0}
+          override <- list()
 
-      - name: Get pkgdown destination
-        if: github.event_name == 'pull_request'
-        id: pkgdown-dest
-        run: |
-          echo "folder=$(Rscript -e 'cat(fs::path_rel(pkgdown::as_pkgdown(".", override = list(destination = "docs"))$dst_path))')" >> "$GITHUB_OUTPUT"
+          pr_number <- Sys.getenv("PR_NUMBER")
+          if (nzchar(pr_number)) {
+            pkg <- pkgdown::as_pkgdown(".")
+
+            if (pkg$development$mode == "devel") {
+              Sys.setenv(PKGDOWN_DEV_MODE = "unreleased")
+            }
+
+            override <- list(
+              url = paste0(pkg$meta$url, "/pr/", pr_number),
+              template = list(
+                params = list(noindex = TRUE)
+              )
+            )
+          }
+
+          pkgdown::build_site_github_pages(
+            lazy = FALSE,
+            run_dont_run = TRUE,
+            new_process = TRUE,
+            override = override
+          )
+        shell: Rscript {0}
 
       - name: Deploy PR preview
         # Forks cannot deploy the site
@@ -61,7 +83,7 @@ jobs:
         uses: JamesIves/github-pages-deploy-action@v4
         with:
           branch: gh-pages
-          folder: ${{ steps.pkgdown-dest.outputs.folder }}
+          folder: docs
           target-folder: pr/${{ github.event.pull_request.number }}
           clean: true
           force: false
@@ -74,3 +96,37 @@ jobs:
           folder: docs
           clean: false
           force: false
+  cleanup-preview:
+    if: >-
+      github.event_name == 'pull_request' && github.event.action == 'closed'
+      && github.event.pull_request.head.repo.full_name == github.repository
+    runs-on: ubuntu-latest
+
+    concurrency:
+      group: pkgdown-${{ github.event.pull_request.number }}
+      cancel-in-progress: true
+
+    permissions:
+      contents: write
+
+    steps:
+      - uses: actions/checkout@v7
+        with:
+          ref: gh-pages
+
+      - name: Remove PR preview
+        env:
+          PR_NUMBER: ${{ github.event.pull_request.number }}
+        run: |
+          git config user.name "github-actions[bot]"
+          git config user.email "41898282+github-actions[bot]@users.noreply.github.com"
+
+          git rm -r --ignore-unmatch "pr/$PR_NUMBER"
+
+          if git diff --cached --quiet; then
+            exit 0
+          fi
+
+          git commit -m "Remove pkgdown preview for PR #$PR_NUMBER"
+          git pull --rebase origin gh-pages
+          git push origin HEAD:gh-pages