ci(pages): judge the demo boot with shinylive-check, before deploy and live after it

The build job now runs shinylive-check against the local-URL export before the
app-specific behavior script, keeping a full-page screenshot as an artifact when
the boot fails. A new post-deploy verify job probes the live Pages URL, the
first check to see the public-URL rebuild that actually ships.

Author: rvben

.github/workflows/pages.yml

@@ -1,8 +1,9 @@
 name: Pages
 
 # Builds the shinylive demo from the current checkout and deploys it to GitHub Pages,
-# after proving in a real browser that it renders (make site-check). Every step is a
-# make target, so the same build and the same proof run locally.
+# after proving in a real browser that it renders (make site-check), then probes the
+# live site once deployed (make site-verify). Every step is a make target, so the
+# same build and the same proofs run locally.
 
 on:
   push:
@@ -41,6 +42,14 @@ jobs:
       - name: Build the site and prove it renders
         run: make site-check
 
+      - name: Keep the evidence when the boot check fails
+        if: failure()
+        uses: actions/upload-artifact@v7
+        with:
+          name: boot-failure
+          path: tmp/boot-failure.png
+          if-no-files-found: ignore
+
       - name: Rebuild against the public URL
         run: make site SITE_URL=https://rvben.github.io/shiny-plotly
 
@@ -59,3 +68,28 @@ jobs:
     steps:
       - id: deployment
         uses: actions/deploy-pages@v4
+
+  # The build job checks the local-URL export; what ships is the public-URL rebuild,
+  # whose wheel URL only exists once deployed. Probe the live site so a deploy that
+  # boots broken fails the workflow instead of sitting green.
+  verify:
+    needs: deploy
+    runs-on: ubuntu-latest
+    timeout-minutes: 15
+    steps:
+      - uses: actions/checkout@v7
+
+      - uses: astral-sh/setup-uv@v10.0.1
+        with:
+          version: "0.12.5"
+          python-version: "3.12"
+          enable-cache: true
+
+      - name: Sync
+        run: make sync
+
+      - name: Install Chromium
+        run: make browsers PLAYWRIGHT_ARGS=--with-deps
+
+      - name: Boot the live site in Chromium
+        run: make site-verify

Makefile

@@ -1,6 +1,6 @@
 .PHONY: sync lock-check browsers lint fmt typecheck test test-browser test-all build check-wheel \
 	check-floor bench bench-events check version check-version release-notes publish clean \
-	site site-check release-patch release-minor release-major
+	site site-check site-verify release-patch release-minor release-major
 
 # Every CI step is one of these targets; the workflows only call make.
 
@@ -89,7 +89,8 @@ bench-events:
 # Pinned: the demo build runs only in the Pages workflow, so a shinylive release
 # could break the deploy with no CI run ever having seen it. Bump deliberately.
 SHINYLIVE_VERSION := 0.8.11
-SITE_URL ?= http://127.0.0.1:8008
+SITE_PORT := 8008
+SITE_URL ?= http://127.0.0.1:$(SITE_PORT)
 
 # Exports the shinylive demo app with the wheel built from this checkout, so the
 # deployed demo tracks main, not PyPI. The committed examples/shinylive stays a
@@ -105,12 +106,24 @@ site: build
 	mkdir -p site/wheels
 	cp dist/*.whl site/wheels/
 
-# Serves the exported site and proves the demo renders in Chromium: pyodide boots,
-# the wheel installs, the stream ticks, the Explore tab draws. The Pages workflow
-# runs this before rebuilding with the public URL and deploying.
+# Proves the export in two passes. shinylive-check judges the boot generically
+# (console and page errors, output errors, a screenshot artifact on failure; it must
+# serve on SITE_PORT because the export references its wheel by that absolute URL).
+# tools/site_check.py then proves the app-specific behavior a boot check cannot:
+# the stream ticks and the Explore tab draws. The Pages workflow runs this before
+# rebuilding with the public URL and deploying.
 site-check: site
+	mkdir -p tmp
+	uv run shinylive-check site --port $(SITE_PORT) --screenshot tmp/boot-failure.png
 	uv run python tools/site_check.py --site site --url $(SITE_URL)
 
+# Probes the deployed demo after the Pages deploy. The public-URL rebuild that
+# actually ships can only be proven live (its wheel URL does not exist before the
+# deploy), so this is the first check that sees what visitors get.
+PAGES_URL ?= https://rvben.github.io/shiny-plotly/
+site-verify:
+	uv run shinylive-check $(PAGES_URL)
+
 # The version in pyproject.toml, the single source for the package version.
 version:
 	@sed -n 's/^version = "\(.*\)"$$/\1/p' pyproject.toml

pyproject.toml

@@ -58,6 +58,7 @@ dev = [
   "pytest-playwright>=0.9.0",
   "numpy>=1.26",
   "brotli>=1.1",
+  "shinylive-check>=0.1.0",
 ]
 
 # uv's default cache keys for a local build are the metadata files only, so a source-only