Run CI checks and screenshots per wallpaper in parallel

.github/workflows/ci.yml

@@ -10,7 +10,7 @@ concurrency:
   cancel-in-progress: true
 
 jobs:
-  check:
+  build:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v7
@@ -25,11 +25,47 @@ jobs:
       - run: bun run typecheck
       # The npm package's dist/: the compiled plugin, the wallpaper API and its declarations.
       - run: bun run build
+
+  # Lists the registered wallpapers, so the jobs below run one per wallpaper in parallel and pick up new ones.
+  wallpapers:
+    runs-on: ubuntu-latest
+    outputs:
+      ids: ${{ steps.list.outputs.ids }}
+    steps:
+      - uses: actions/checkout@v7
+      - uses: oven-sh/setup-bun@v2
+        with:
+          bun-version: 1.3.14
+      - id: list
+        run: echo "ids=$(bun -e 'import { WALLPAPERS } from "./wallpapers"; console.log(JSON.stringify(WALLPAPERS.map((w) => w.id)))')" >> "$GITHUB_OUTPUT"
+
+  check:
+    needs: wallpapers
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        wallpaper: ${{ fromJSON(needs.wallpapers.outputs.ids) }}
+    steps:
+      - uses: actions/checkout@v7
+      - uses: oven-sh/setup-bun@v2
+        with:
+          bun-version: 1.3.14
+      - uses: actions/cache@v6
+        with:
+          path: ~/.bun/install/cache
+          key: bun-${{ runner.os }}-${{ hashFiles('bun.lock') }}
+      - run: bun install --frozen-lockfile
       # Fails on errors and flicker; the frame budget is generous because CI machines are slower and noisier.
-      - run: bun dev/check.ts --quiet --max-ms=60
+      - run: bun dev/check.ts --quiet --max-ms=60 ${{ matrix.wallpaper }}
 
   screenshots:
+    needs: wallpapers
     runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        wallpaper: ${{ fromJSON(needs.wallpapers.outputs.ids) }}
     steps:
       - uses: actions/checkout@v7
       - uses: oven-sh/setup-bun@v2
@@ -40,9 +76,9 @@ jobs:
           path: ~/.bun/install/cache
           key: bun-${{ runner.os }}-${{ hashFiles('bun.lock') }}
       - run: bun install --frozen-lockfile
-      - run: bun run screenshots
+      - run: bun dev/screenshots.ts ${{ matrix.wallpaper }}
       - if: failure()
         uses: actions/upload-artifact@v7
         with:
-          name: fresh-screenshots
-          path: dev/out/*-45s.png
+          name: fresh-screenshots-${{ matrix.wallpaper }}
+          path: dev/out/${{ matrix.wallpaper }}-*-45s.png

dev/screenshots.ts

@@ -1,12 +1,16 @@
 // Re-renders the README gallery (teeming at 45 s via dev/snap.ts) and fails if any screenshot differs from the
-// committed one beyond a tiny tolerance; --update writes the fresh renders instead: bun dev/screenshots.ts [--update]
+// committed one beyond a tiny tolerance; --update writes the fresh renders instead. Naming wallpapers limits it to them:
+// bun dev/screenshots.ts [--update] [wallpaper...]
 import { availableParallelism } from "node:os"
 import { TIMES } from "../src/engine"
 import { WALLPAPERS } from "../wallpapers"
 import { decodePng } from "./png"
 
 const update = process.argv.includes("--update")
-const shots = WALLPAPERS.flatMap((w) => TIMES.map((time) => ({ id: w.id, time, file: `screenshots/${w.id}${time === "day" ? "" : `-${time}`}.png` })))
+const ids = process.argv.slice(2).filter((arg) => !arg.startsWith("--"))
+const unknown = ids.filter((id) => !WALLPAPERS.some((w) => w.id === id))
+if (unknown.length) throw new Error(`unknown wallpaper ${unknown.join(", ")}`)
+const shots = (ids.length ? WALLPAPERS.filter((w) => ids.includes(w.id)) : WALLPAPERS).flatMap((w) => TIMES.map((time) => ({ id: w.id, time, file: `screenshots/${w.id}${time === "day" ? "" : `-${time}`}.png` })))
 const queue = [...shots]
 const stale: string[] = []
 await Promise.all(