ci: track tree-shaken scenario sizes per PR with size-limit (#2883)

.github/workflows/size.yml

@@ -0,0 +1,57 @@
+name: Size
+
+# Tracks tree-shaken scenario costs per PR (#2883). scripts/size/ is a
+# standalone npm package OUTSIDE the pnpm workspace on purpose: adding its
+# tooling to the workspace graph re-keys pnpm peer instances (vitest,
+# @codspeed/vitest-plugin), which relocates the benchmark harness and shows
+# up as phantom CodSpeed regressions. The limits in size/.size-limit.js are
+# the strict tree-shaking gate; the retained-module-graph assertions in
+# packages/solid-signals/tests/treeshake.test.ts stay the which-module
+# diagnostic underneath.
+on:
+  pull_request:
+    branches: [main, next]
+
+permissions:
+  contents: read
+  pull-requests: write
+
+jobs:
+  # The hard gate: self-contained on the PR head, fails when any scenario
+  # exceeds its limit. Never depends on the base branch.
+  check:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: pnpm/action-setup@v4
+      - uses: actions/setup-node@v4
+        with:
+          node-version-file: ".nvmrc"
+          cache: pnpm
+      - run: pnpm install --frozen-lockfile
+      - run: pnpm build
+      - run: npm ci --no-audit --no-fund
+        working-directory: scripts/size
+      - run: npm run size
+        working-directory: scripts/size
+
+  # Best-effort base-vs-head delta comment. Requires the base branch to also
+  # carry scripts/size/, so it is informational and never blocks: continue-on-error
+  # keeps bootstrap PRs (and any action hiccup) green.
+  compare:
+    runs-on: ubuntu-latest
+    continue-on-error: true
+    steps:
+      - uses: actions/checkout@v4
+      - uses: pnpm/action-setup@v4
+      - uses: actions/setup-node@v4
+        with:
+          node-version-file: ".nvmrc"
+          cache: pnpm
+      - uses: andresz1/size-limit-action@v1
+        continue-on-error: true
+        with:
+          github_token: ${{ secrets.GITHUB_TOKEN }}
+          package_manager: npm
+          directory: scripts/size
+          build_script: build

scripts/size/.gitignore

@@ -0,0 +1 @@
+node_modules

scripts/size/.size-limit.js

@@ -0,0 +1,48 @@
+// Import-cost scenarios for #2883, measured against the built browser-prod
+// artifacts. Bare specifiers resolve via esbuild aliases so nothing here
+// touches the workspace dependency graph. Limits carry ~5% headroom over the
+// sizes at landing: a breach means tree-shaking regressed (or a deliberate
+// feature landed — bump the limit in the same PR and say why). The simple-app
+// scenario is pinned at 10 KB on purpose.
+const alias = {
+  "solid-js": "../../packages/solid/dist/solid.js",
+  "@solidjs/web": "../../packages/solid-web/dist/web.js",
+  "@solidjs/signals": "../../packages/solid-signals/dist/prod/index.js"
+};
+const modifyEsbuildConfig = config => ({ ...config, alias });
+
+module.exports = [
+  {
+    name: "signals: core floor (createSignal/Memo/Effect/Root/flush)",
+    path: "../../packages/solid-signals/dist/prod/index.js",
+    import: "{ createSignal, createMemo, createEffect, createRoot, flush }",
+    limit: "7.1 KB",
+    modifyEsbuildConfig
+  },
+  {
+    name: "signals: + createStore",
+    path: "../../packages/solid-signals/dist/prod/index.js",
+    import: "{ createSignal, createMemo, createEffect, createRoot, flush, createStore }",
+    limit: "11.6 KB",
+    modifyEsbuildConfig
+  },
+  {
+    name: "signals: + isPending/latest",
+    path: "../../packages/solid-signals/dist/prod/index.js",
+    import: "{ createSignal, createMemo, createEffect, createRoot, flush, isPending, latest }",
+    limit: "8.75 KB",
+    modifyEsbuildConfig
+  },
+  {
+    name: "app: render + one signal (the simple-app floor)",
+    path: "minimal-app.js",
+    limit: "10 KB",
+    modifyEsbuildConfig
+  },
+  {
+    name: "app: CSR with Show/For/Loading/Errored/lazy",
+    path: "csr-app.js",
+    limit: "12 KB",
+    modifyEsbuildConfig
+  }
+];

scripts/size/README.md

@@ -0,0 +1,19 @@
+# Size scenarios (#2883)
+
+Tree-shaken import-cost tracking: `.size-limit.js` defines scenario entries
+(signals floor, +createStore, +isPending/latest, the render+one-signal simple
+app, a representative CSR app) with hard gzip-limits. CI fails when a scenario
+exceeds its limit — that means tree-shaking regressed, or a deliberate feature
+landed and the limit should be bumped in the same PR with a reason. The
+simple-app scenario is pinned at 10 KB on purpose.
+
+This directory is deliberately **outside the pnpm workspace**, with its own
+npm lockfile. Its tooling must never enter the workspace dependency graph:
+changing that graph re-keys pnpm peer instances (vitest,
+@codspeed/vitest-plugin), which relocates the benchmark harness and shows up
+as phantom CodSpeed regressions. Nothing here is published (`private: true`).
+
+Run locally: `cd scripts/size && npm ci && npm run size` (build the repo
+first). The retained-module-graph test in
+`packages/solid-signals/tests/treeshake.test.ts` is the companion diagnostic
+that names the re-coupled module when shaking breaks.

scripts/size/csr-app.js

@@ -0,0 +1,11 @@
+// A representative CSR app surface: flow components, boundaries, lazy.
+import { render, Show, For, Loading, Errored } from "@solidjs/web";
+import { createSignal, createMemo, lazy } from "solid-js";
+
+const [n, setN] = createSignal(0);
+const Page = lazy(() => import("./lazy-page.js"));
+render(() => {
+  const d = createMemo(() => n() + 1);
+  setN(1);
+  return [d(), Show, For, Loading, Errored, Page];
+}, document.body);

scripts/size/lazy-page.js

@@ -0,0 +1 @@
+export default () => "page";

scripts/size/minimal-app.js

@@ -0,0 +1,11 @@
+// The "simple app" floor: render + one signal. Tracks the tree-shaken cost a
+// hello-world CSR app ships (#2883).
+import { render } from "@solidjs/web";
+import { createSignal } from "solid-js";
+
+const [count, setCount] = createSignal(0);
+render(() => {
+  const el = document.createElement("button");
+  el.onclick = () => setCount(count() + 1);
+  return el;
+}, document.getElementById("app"));