fix: dedupe solid-js in production builds

.changeset/dedupe-solid-in-builds.md

@@ -0,0 +1,5 @@
+---
+'vite-plugin-solid': patch
+---
+
+Production builds now dedupe `solid-js` the same way dev does. A dependency with its own nested copy of `solid-js` no longer adds a second runtime to the bundle, which broke context lookups (#112).

.github/workflows/vitest.yml

@@ -27,6 +27,9 @@ jobs:
       - name: Install project dependencies
         run: pnpm i
 
+      - name: Run unit tests
+        run: pnpm run test:unit
+
       - name: Install playwright browser
         working-directory: examples/vite-6
         run: pnpm exec playwright install chromium

package.json

@@ -22,7 +22,8 @@
     "prepublishOnly": "pnpm build",
     "release": "pnpm build && changeset publish",
     "check": "package-check",
-    "test": "node scripts/test-examples.ts"
+    "test": "node scripts/test-examples.ts",
+    "test:unit": "vitest run"
   },
   "repository": {
     "type": "git",
@@ -68,7 +69,8 @@
     "rollup-plugin-cleaner": "^1.0.0",
     "solid-js": "^1.9.3",
     "typescript": "^5.2.2",
-    "vite": "^6.0.0"
+    "vite": "^6.0.0",
+    "vitest": "^3.0.7"
   },
   "peerDependencies": {
     "@testing-library/jest-dom": "^5.16.6 || ^5.17.0 || ^6.0.0 || ^7.0.0",

src/dedupe.test.ts

@@ -0,0 +1,67 @@
+import { mkdtemp, mkdir, rm, writeFile } from 'node:fs/promises';
+import { tmpdir } from 'node:os';
+import path from 'node:path';
+import { build, type Rollup } from 'vite';
+import { afterAll, beforeAll, describe, expect, it } from 'vitest';
+import solidPlugin from './index.js';
+
+let root: string;
+
+async function writePackage(dir: string, pkg: Record<string, unknown>, files: Record<string, string>) {
+  await mkdir(dir, { recursive: true });
+  await writeFile(path.join(dir, 'package.json'), JSON.stringify(pkg));
+  for (const [name, code] of Object.entries(files)) {
+    await writeFile(path.join(dir, name), code);
+  }
+}
+
+beforeAll(async () => {
+  root = await mkdtemp(path.join(tmpdir(), 'solid-dedupe-'));
+  const fakeSolid = (copy: string) =>
+    [
+      { name: 'solid-js', version: '1.9.0', type: 'module', exports: { '.': './index.js' } },
+      { 'index.js': `export const copy = ${JSON.stringify(copy)};\n` },
+    ] as const;
+  await writePackage(path.join(root, 'node_modules/solid-js'), ...fakeSolid('root'));
+  // A dependency that ships its own nested copy of solid-js.
+  const lib = path.join(root, 'node_modules/lib');
+  await writePackage(
+    lib,
+    { name: 'lib', version: '1.0.0', type: 'module', exports: { '.': './index.js' } },
+    { 'index.js': "export { copy as libCopy } from 'solid-js';\n" },
+  );
+  await writePackage(path.join(lib, 'node_modules/solid-js'), ...fakeSolid('nested'));
+  await writeFile(path.join(root, 'package.json'), JSON.stringify({ name: 'app', type: 'module' }));
+  await writeFile(
+    path.join(root, 'entry.js'),
+    "import { copy } from 'solid-js';\nimport { libCopy } from 'lib';\nexport const copies = [copy, libCopy];\n",
+  );
+});
+
+afterAll(async () => {
+  await rm(root, { recursive: true, force: true });
+});
+
+describe('resolve.dedupe', () => {
+  // #112: dev deduped solid-js, but production builds bundled the nested copy too.
+  it('bundles a single solid-js copy in production builds', async () => {
+    const result = (await build({
+      root,
+      configFile: false,
+      logLevel: 'silent',
+      plugins: [solidPlugin()],
+      build: {
+        write: false,
+        minify: false,
+        rollupOptions: { input: path.join(root, 'entry.js'), preserveEntrySignatures: 'strict' },
+      },
+    })) as Rollup.RollupOutput | Rollup.RollupOutput[];
+    const output = Array.isArray(result) ? result[0] : result;
+    const code = output.output
+      .filter((chunk): chunk is Rollup.OutputChunk => chunk.type === 'chunk')
+      .map((chunk) => chunk.code)
+      .join('\n');
+    expect(code).toContain('"root"');
+    expect(code).not.toContain('"nested"');
+  });
+});

src/index.ts

@@ -237,10 +237,9 @@ export default function solidPlugin(options: Partial<Options> = {}): Plugin {
         },
       });
 
+      const solidDeps = ['solid-js', 'solid-js/web', 'solid-js/store', 'solid-js/html', 'solid-js/h'];
       // fix for bundling dev in production
-      const nestedDeps = replaceDev
-        ? ['solid-js', 'solid-js/web', 'solid-js/store', 'solid-js/html', 'solid-js/h']
-        : [];
+      const nestedDeps = replaceDev ? solidDeps : [];
 
       const userTest = (userConfig as any).test ?? {};
       const test = {} as any;
@@ -286,7 +285,9 @@ export default function solidPlugin(options: Partial<Options> = {}): Plugin {
                 ...(replaceDev ? ['development'] : []),
                 ...(userConfig.mode === 'test' && !options.ssr ? ['browser'] : []),
               ],
-          dedupe: nestedDeps,
+          // Dedupe in builds too. A dependency that ships its own nested
+          // solid-js would otherwise add a second runtime to the bundle. #112
+          dedupe: solidDeps,
           alias: [{ find: /^solid-refresh$/, replacement: runtimePublicPath }],
         },
         optimizeDeps: {

tsconfig.json

@@ -3,7 +3,7 @@
     "src", "cypress"
   ],
   "exclude": [
-    "**/*.spec.ts"
+    "**/*.spec.ts", "**/*.test.ts"
   ],
   "compilerOptions": {
     "target": "ESNext",

vitest.config.ts

@@ -0,0 +1,10 @@
+import { defineConfig } from 'vitest/config';
+
+// The plugin's own unit tests (`pnpm test:unit`). The example apps under
+// examples/* carry their own vitest configs and run through `pnpm test`.
+export default defineConfig({
+  test: {
+    include: ['src/**/*.test.ts'],
+    environment: 'node',
+  },
+});