fix(meta): define build banner globals as writable

.github/workflows/main.yaml

@@ -21,6 +21,8 @@ jobs:
           node-version-file: '.nvmrc'
       - name: Install Dependencies
         run: pnpm install --frozen-lockfile
+      - name: Generate Prisma
+        run: pnpm prisma:generate
       - name: Lint
         run: pnpm run lint
       - name: Test
@@ -30,4 +32,3 @@ jobs:
         with:
           directory: ./coverage/
           token: ${{ secrets.CODECOV_TOKEN }}
-

src/meta/__tests__/globals-banner.test.ts

@@ -0,0 +1,68 @@
+import { execFile } from 'node:child_process';
+import * as fs from 'node:fs';
+import * as os from 'node:os';
+import * as path from 'node:path';
+import { promisify } from 'node:util';
+
+import { afterAll, beforeAll, describe, expect, it } from 'vitest';
+
+import { GLOBALS_BANNER } from '../build.js';
+
+const execFileAsync = promisify(execFile);
+
+/**
+ * The banner that `@prisma/client` >= 6.19.0 prepends to its ESM runtime, which esbuild inlines into
+ * the application bundle verbatim. The assignment to `globalThis` is the part that matters.
+ */
+const DEPENDENCY_BANNER = [
+  'import * as __banner_node_path from "node:path";',
+  'import * as __banner_node_url from "node:url";',
+  'const __filename = __banner_node_url.fileURLToPath(import.meta.url);',
+  "globalThis['__dirname'] = __banner_node_path.dirname(__filename);"
+].join('\n');
+
+describe('GLOBALS_BANNER', () => {
+  let outdir: string;
+
+  beforeAll(async () => {
+    outdir = await fs.promises.mkdtemp(path.join(os.tmpdir(), 'globals-banner-'));
+  });
+
+  afterAll(async () => {
+    await fs.promises.rm(outdir, { force: true, recursive: true });
+  });
+
+  it('should define the commonjs globals', () => {
+    expect(GLOBALS_BANNER).toContain('__dirname');
+    expect(GLOBALS_BANNER).toContain('__filename');
+    expect(GLOBALS_BANNER).toContain('require');
+  });
+
+  it('should not leave a bundled dependency unable to assign to globalThis', { timeout: 30000 }, async () => {
+    const esbuild = await import('esbuild');
+    const sourceDir = path.join(outdir, 'src');
+    await fs.promises.mkdir(sourceDir, { recursive: true });
+    await fs.promises.writeFile(
+      path.join(sourceDir, 'dependency.js'),
+      `${DEPENDENCY_BANNER}\nexport const value = 'ok';\n`
+    );
+    await fs.promises.writeFile(
+      path.join(sourceDir, 'entry.js'),
+      "import { value } from './dependency.js';\nconsole.log(value);\n"
+    );
+
+    const outfile = path.join(outdir, 'server.js');
+    await esbuild.build({
+      banner: { js: GLOBALS_BANNER },
+      bundle: true,
+      entryPoints: [path.join(sourceDir, 'entry.js')],
+      format: 'esm',
+      outfile,
+      platform: 'node'
+    });
+
+    // a non-writable property makes the inlined assignment throw, so the bundle dies before this resolves
+    const { stdout } = await execFileAsync(process.execPath, [outfile]);
+    expect(stdout.trim()).toBe('ok');
+  });
+});

src/meta/build.ts

@@ -14,6 +14,19 @@ import { swcPlugin } from './plugins/swc.js';
 
 import type { UserConfigOptions } from '../user-config.js';
 
+/**
+ * The banner prepended to the production bundle, which backfills the CommonJS globals that some
+ * dependencies expect to exist at runtime.
+ *
+ * These are defined `writable: true` deliberately. Some dependencies ship an esbuild-style banner of
+ * their own that assigns to `globalThis['__dirname']` (`@prisma/client` >= 6.19.0 does). Once inlined
+ * into this bundle, that assignment runs in module scope, where a non-writable property makes it throw
+ * `TypeError: Cannot assign to read only property` instead of failing silently, killing the process
+ * before the app bootstraps.
+ */
+export const GLOBALS_BANNER =
+  "Object.defineProperties(globalThis, { __dirname: { value: import.meta.dirname, writable: true }, __filename: { value: import.meta.filename, writable: true }, require: { value: (await import('module')).createRequire(import.meta.url), writable: true } });";
+
 export function buildProd({
   configFile,
   verbose
@@ -63,7 +76,7 @@ export function buildProd({
 
       await esbuild.build({
         banner: {
-          js: "Object.defineProperties(globalThis, { __dirname: { value: import.meta.dirname, writable: false }, __filename: { value: import.meta.filename, writable: false }, require: { value: (await import('module')).createRequire(import.meta.url), writable: false } });"
+          js: GLOBALS_BANNER
         },
         bundle: true,
         define,