Function assertPackedWorkerBundler

apps/cli/src/build.ts:107–138

(binDir: string, targetName: string)

 * cannot pass as real.
 */
const assertPackedWorkerBundler = async (binDir: string, targetName: string): Promise<void> => {
  const stagedDir = join(binDir, WORKER_BUNDLER_DIRNAME);

  const missing = missingWorkerBundlerFiles(stagedDir, existsSync);
  if (missing.length > 0) {
    throw new Error(
      `Packed @cloudflare/worker-bundler is incomplete for ${targetName}: missing ${missing.join(", ")} under ${stagedDir}. ` +
        `The compiled binary resolves this package from disk, not from bunfs, so shipping it partial means a runtime failure on the user's machine.`,
    );
  }

  const bundledEntry = join(stagedDir, "dist", "index.bundled.js");
  const bundledSize = (await Bun.file(bundledEntry).arrayBuffer()).byteLength;
  if (bundledSize < 100_000) {
    throw new Error(
      `Packed worker-bundler entry for ${targetName} is implausibly small (${bundledSize} bytes at ${bundledEntry}). Expected the esbuild-packed bundle.`,
    );
  }

  const wasmPath = join(stagedDir, "dist", "esbuild.wasm");
  const wasmHead = new Uint8Array((await Bun.file(wasmPath).arrayBuffer()).slice(0, 4));
  if (
    wasmHead[0] !== 0x00 ||
    wasmHead[1] !== 0x61 ||
    wasmHead[2] !== 0x73 ||
    wasmHead[3] !== 0x6d
  ) {
    throw new Error(
      `Staged esbuild.wasm for ${targetName} is not a WebAssembly module (bad magic at ${wasmPath}).`,
    );
  }
};

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