callstack · Anber · Jan 26, 2026 · Jan 26, 2026 · Jan 26, 2026
diff --git a/.changeset/bump-wyw-1-0-x.md b/.changeset/bump-wyw-1-0-x.md
@@ -0,0 +1,22 @@
+---
+'@linaria/atomic': major
+'@linaria/babel-plugin-interop': major
+'@linaria/core': major
+'@linaria/postcss-linaria': major
+'@linaria/react': major
+'@linaria/server': major
+'@linaria/stylelint': major
+'@linaria/stylelint-config-standard-linaria': major
+'@linaria/testkit': major
+linaria: major
+---
+
+BREAKING: bump `@wyw-in-js/*` dependencies to `^1.0.0` (stable).
+
+This release updates Linaria's build-time evaluation engine (WyW). See https://wyw-in-js.dev/stability for practical guidance and common pitfalls.
+
+Notes:
+
+- If you import JSON from code that is evaluated by WyW, add `.json` to `extensions` and ensure `.json` is ignored by evaluation rules (so it's parsed as JSON, not by Babel).
+- Rollup users: WyW 1.x serializes `transform()` by default (`serializeTransform: true`). If you hit Rollup "Unexpected early exit" (unresolved plugin promises / deadlock during resolve), set `serializeTransform: false` (see `examples/rollup/rollup.config.mjs`).
+- WyW 1.x promotes fully-statically-evaluatable modules to `only: ['*']` and can re-evaluate modules when cached exports are incomplete (cached export values might not be reused).
diff --git a/README.md b/README.md
@@ -61,6 +61,12 @@ Linaria is now built on top of [wyw-in-js.dev](https://wyw-in-js.dev/). It suppo
 
 See [Configuration](https://wyw-in-js.dev/configuration) to customize how Linaria processes your files.
 
+## Stability
+
+Linaria relies on WyW (`@wyw-in-js/*`) to evaluate your modules at build time and extract CSS. If you hit issues like slow builds, invalidation storms, or unexpected code being executed during the build, it’s usually related to the WyW evaluation model and how your modules are structured.
+
+See https://wyw-in-js.dev/stability for practical guidance and common pitfalls.
+
 ## Syntax
 
 Linaria can be used with any framework, with additional helpers for React. The basic syntax looks like this:

diff --git a/docs/MIGRATION_GUIDE.md b/docs/MIGRATION_GUIDE.md
@@ -1,5 +1,16 @@
 # Migration Guide
 
+# 7.x from 6.x
+
+## For Users
+
+Linaria 7 updates the WyW toolchain (`@wyw-in-js/*`) to `^1.0.0` (stable). This affects build-time evaluation (CSS extraction) and can surface previously hidden issues in evaluated modules.
+
+- Review https://wyw-in-js.dev/stability for the evaluation model, common pitfalls, and performance guidance.
+- If you rely on WyW cache internals, note that WyW 1.x can promote fully-statically-evaluatable modules to `only: ['*']` and may re-evaluate modules when cached exports are incomplete.
+- If you import JSON from code that is evaluated by WyW, add `.json` to `extensions` and ensure `.json` is ignored by evaluation rules (so it's parsed as JSON, not by Babel).
+- Rollup users on WyW 1.0.6: WyW serializes `transform()` by default; if you hit Rollup "Unexpected early exit" (unresolved plugin promises), try `serializeTransform: false` in the WyW Rollup plugin config.
+
 # 6.x from 5.x, 4.x, 3.x
 
 ## For Users

diff --git a/examples/astro-solid/package.json b/examples/astro-solid/package.json
@@ -8,7 +8,7 @@
     "@astrojs/solid-js": "^1.2.3",
     "@babel/core": "^7.23.5",
     "@linaria/core": "workspace:^",
-    "@wyw-in-js/vite": "^0.6.0",
+    "@wyw-in-js/vite": "^1.0.6",
     "astro": "^1.6.10",
     "solid-js": "^1.6.2",
     "vite": "^3",

diff --git a/examples/esbuild/package.json b/examples/esbuild/package.json
@@ -7,7 +7,7 @@
     "linaria-website": "workspace:^"
   },
   "devDependencies": {
-    "@wyw-in-js/esbuild": "^0.6.0",
+    "@wyw-in-js/esbuild": "^1.0.6",
     "esbuild": "^0.15.16"
   },
   "scripts": {

diff --git a/examples/rollup/package.json b/examples/rollup/package.json
@@ -13,8 +13,8 @@
     "@rollup/plugin-commonjs": "^25.0.4",
     "@rollup/plugin-image": "^3.0.2",
     "@rollup/plugin-node-resolve": "^15.2.1",
-    "@wyw-in-js/rollup": "^0.6.0",
-    "rollup": "^3.29.5",
+    "@wyw-in-js/rollup": "^1.0.6",
+    "rollup": "^4.0.0",
     "rollup-plugin-css-only": "^4.3.0"
   },
   "scripts": {

diff --git a/examples/rollup/rollup.config.mjs b/examples/rollup/rollup.config.mjs
@@ -15,6 +15,8 @@ export default {
     image(),
     wyw({
       sourceMap: process.env.NODE_ENV !== 'production',
+      // Rollup can deadlock when WyW resolves imports during transform.
+      serializeTransform: false,
     }),
     css({
       output: 'styles.css',

diff --git a/examples/vite/package.json b/examples/vite/package.json
@@ -11,7 +11,7 @@
   "devDependencies": {
     "@rollup/plugin-node-resolve": "^15.2.1",
     "@vitejs/plugin-react": "^2.1.0",
-    "@wyw-in-js/vite": "^0.6.0",
+    "@wyw-in-js/vite": "^1.0.6",
     "vite": "^3.2.10"
   },
   "scripts": {

diff --git a/examples/vpssr-linaria-solid/package.json b/examples/vpssr-linaria-solid/package.json
@@ -11,7 +11,7 @@
   "license": "ISC",
   "dependencies": {
     "@linaria/core": "workspace:^",
-    "@wyw-in-js/vite": "^0.6.0",
+    "@wyw-in-js/vite": "^1.0.6",
     "babel-preset-solid": "^1.6.2",
     "compression": "^1.7.4",
     "express": "^4.20.0",

diff --git a/examples/webpack5/package.json b/examples/webpack5/package.json
@@ -9,7 +9,7 @@
   },
   "devDependencies": {
     "@babel/core": "^7.23.5",
-    "@wyw-in-js/webpack-loader": "^0.6.0",
+    "@wyw-in-js/webpack-loader": "^1.0.6",
     "babel-loader": "^9.1.0",
     "cross-env": "^7.0.3",
     "css-hot-loader": "^1.4.4",

diff --git a/packages/atomic/package.json b/packages/atomic/package.json
@@ -51,8 +51,8 @@
   "dependencies": {
     "@linaria/core": "workspace:^",
     "@linaria/react": "workspace:^",
-    "@wyw-in-js/processor-utils": "^0.6.0",
-    "@wyw-in-js/shared": "^0.6.0",
+    "@wyw-in-js/processor-utils": "^1.0.4",
+    "@wyw-in-js/shared": "^1.0.4",
     "known-css-properties": "^0.24.0",
     "postcss": "^8.4.31",
     "stylis": "^4.3.0",

diff --git a/packages/core/package.json b/packages/core/package.json
@@ -58,7 +58,7 @@
     "watch": "pnpm build:dist --watch & pnpm build:declarations --watch"
   },
   "dependencies": {
-    "@wyw-in-js/processor-utils": "^0.6.0"
+    "@wyw-in-js/processor-utils": "^1.0.4"
   },
   "devDependencies": {
     "@babel/traverse": "^7.23.5",

diff --git a/packages/react/package.json b/packages/react/package.json
@@ -60,8 +60,8 @@
   "dependencies": {
     "@emotion/is-prop-valid": "^1.2.0",
     "@linaria/core": "workspace:^",
-    "@wyw-in-js/processor-utils": "^0.6.0",
-    "@wyw-in-js/shared": "^0.6.0",
+    "@wyw-in-js/processor-utils": "^1.0.4",
+    "@wyw-in-js/shared": "^1.0.4",
     "minimatch": "^9.0.3",
     "react-html-attributes": "^1.4.6",
     "resolve": "^1.22.8",

diff --git a/packages/stylelint/package.json b/packages/stylelint/package.json
@@ -30,8 +30,8 @@
     "watch": "pnpm build:lib --watch & pnpm build:esm --watch & pnpm build:declarations --watch"
   },
   "dependencies": {
-    "@wyw-in-js/shared": "^0.6.0",
-    "@wyw-in-js/transform": "^0.6.0"
+    "@wyw-in-js/shared": "^1.0.4",
+    "@wyw-in-js/transform": "^1.0.6"
   },
   "devDependencies": {
     "@types/node": "^17.0.39"

diff --git a/packages/testkit/package.json b/packages/testkit/package.json
@@ -26,9 +26,9 @@
     "@babel/traverse": "^7.23.5",
     "@linaria/react": "workspace:^",
     "@swc/core": "^1.3.20",
-    "@wyw-in-js/processor-utils": "^0.6.0",
-    "@wyw-in-js/shared": "^0.6.0",
-    "@wyw-in-js/transform": "^0.6.0",
+    "@wyw-in-js/processor-utils": "^1.0.4",
+    "@wyw-in-js/shared": "^1.0.4",
+    "@wyw-in-js/transform": "^1.0.6",
     "debug": "^4.3.4",
     "dedent": "^1.5.1",
     "esbuild": "^0.15.16",

diff --git a/packages/testkit/src/__fixtures__/foo-nonstatic.js b/packages/testkit/src/__fixtures__/foo-nonstatic.js
@@ -0,0 +1,3 @@
+export const foo1 = String('foo1');
+export const foo2 = String('foo2');
+export const foo3 = () => 'foo3';