build: Bundle vats with vite

packages/cli/README.md

@@ -6,7 +6,7 @@ Ocap Kernel cli.
 
 ### `ocap bundle <targets..>`
 
-Bundle the supplied file or directory targets. Expects each target to be a `.js` file or a directory containing `.js` files. Each `<file>.js` file will be bundled using `@endo/bundle-source` and written to an associated `<file>.bundle`.
+Bundle the supplied file or directory targets. Expects each target to be a `.js` file or a directory containing `.js` files. Each `<file>.js` file will be bundled using `vite` and written to an associated `<file>.bundle`.
 
 ### `ocap watch <dir>`
 

packages/cli/package.json

@@ -36,8 +36,6 @@
   "dependencies": {
     "@chainsafe/libp2p-noise": "^16.1.3",
     "@chainsafe/libp2p-yamux": "patch:@chainsafe/libp2p-yamux@npm%3A7.0.4#~/.yarn/patches/@chainsafe-libp2p-yamux-npm-7.0.4-284c2f6812.patch",
-    "@endo/bundle-source": "^4.1.2",
-    "@endo/init": "^1.1.12",
     "@endo/promise-kit": "^1.1.13",
     "@libp2p/autonat": "2.0.38",
     "@libp2p/circuit-relay-v2": "3.2.24",
@@ -53,10 +51,12 @@
     "@metamask/snaps-utils": "^11.7.1",
     "@metamask/utils": "^11.9.0",
     "@types/node": "^22.13.1",
+    "acorn": "^8.15.0",
     "chokidar": "^4.0.1",
     "glob": "^11.0.0",
     "libp2p": "2.10.0",
     "serve-handler": "^6.1.6",
+    "vite": "^7.3.0",
     "yargs": "^17.7.2"
   },
   "devDependencies": {
@@ -86,12 +86,12 @@
     "jsdom": "^27.4.0",
     "prettier": "^3.5.3",
     "rimraf": "^6.0.1",
+    "rollup": "^4.55.3",
     "ses": "^1.14.0",
     "turbo": "^2.5.6",
     "typedoc": "^0.28.1",
     "typescript": "~5.8.2",
     "typescript-eslint": "^8.29.0",
-    "vite": "^7.3.0",
     "vitest": "^4.0.16"
   },
   "engines": {

packages/cli/src/app.ts

@@ -1,5 +1,4 @@
-import '@endo/init';
-
+import '@metamask/kernel-shims/endoify';
 import { Logger } from '@metamask/logger';
 import path from 'node:path';
 import yargs from 'yargs';

packages/cli/src/commands/bundle.test.ts

@@ -12,7 +12,7 @@ import { fileExists } from '../file.ts';
 
 const mocks = vi.hoisted(() => {
   return {
-    endoBundleSource: vi.fn(),
+    bundleVat: vi.fn(),
     Logger: vi.fn(
       () =>
         ({
@@ -25,12 +25,10 @@ const mocks = vi.hoisted(() => {
   };
 });
 
-vi.mock('@endo/bundle-source', () => ({
-  default: mocks.endoBundleSource,
+vi.mock('../vite/vat-bundler.ts', () => ({
+  bundleVat: mocks.bundleVat,
 }));
 
-vi.mock('@endo/init', () => ({}));
-
 vi.mock('@metamask/logger', () => ({
   Logger: mocks.Logger,
 }));
@@ -68,8 +66,13 @@ describe('bundle', async () => {
       async ({ source, bundle }) => {
         expect(await fileExists(bundle)).toBe(false);
 
-        const testContent = { source: 'test-content' };
-        mocks.endoBundleSource.mockImplementationOnce(() => testContent);
+        const testContent = {
+          moduleFormat: 'iife',
+          code: 'test-code',
+          exports: [],
+          modules: {},
+        };
+        mocks.bundleVat.mockImplementationOnce(() => testContent);
 
         await bundleFile(source, { logger });
 
@@ -84,7 +87,7 @@ describe('bundle', async () => {
     );
 
     it('throws if bundling fails', async () => {
-      mocks.endoBundleSource.mockImplementationOnce(() => {
+      mocks.bundleVat.mockImplementationOnce(() => {
         throw new Error('test error');
       });
       await expect(
@@ -97,9 +100,12 @@ describe('bundle', async () => {
     it('bundles a directory', async () => {
       expect(await globBundles()).toStrictEqual([]);
 
-      mocks.endoBundleSource.mockImplementation(() => {
-        return 'test content';
-      });
+      mocks.bundleVat.mockImplementation(() => ({
+        moduleFormat: 'iife',
+        code: 'test content',
+        exports: [],
+        modules: {},
+      }));
 
       await bundleDir(testBundleRoot, { logger });
 
@@ -111,7 +117,7 @@ describe('bundle', async () => {
     });
 
     it('throws if bundling fails', async () => {
-      mocks.endoBundleSource.mockImplementationOnce(() => {
+      mocks.bundleVat.mockImplementationOnce(() => {
         throw new Error('test error');
       });
       await expect(bundleDir(testBundleRoot, { logger })).rejects.toThrow(

packages/cli/src/commands/bundle.ts

@@ -1,12 +1,11 @@
-import '@endo/init';
-import endoBundleSource from '@endo/bundle-source';
-import { Logger } from '@metamask/logger';
+import type { Logger } from '@metamask/logger';
 import { glob } from 'glob';
 import { writeFile } from 'node:fs/promises';
 import { resolve, join } from 'node:path';
 
 import { isDirectory } from '../file.ts';
 import { resolveBundlePath } from '../path.ts';
+import { bundleVat } from '../vite/vat-bundler.ts';
 
 type BundleFileOptions = {
   logger: Logger;
@@ -30,7 +29,7 @@ export async function bundleFile(
   const { logger, targetPath } = options;
   const sourceFullPath = resolve(sourcePath);
   const bundlePath = targetPath ?? resolveBundlePath(sourceFullPath);
-  const bundle = await endoBundleSource(sourceFullPath);
+  const bundle = await bundleVat(sourceFullPath);
   const bundleContent = JSON.stringify(bundle);
   await writeFile(bundlePath, bundleContent);
   logger.info(`Wrote ${bundlePath}: ${new Blob([bundleContent]).size} bytes`);

packages/cli/src/commands/watch.ts

@@ -1,4 +1,5 @@
 import { makePromiseKit } from '@endo/promise-kit';
+import type { PromiseKit } from '@endo/promise-kit';
 import { Logger } from '@metamask/logger';
 import { watch } from 'chokidar';
 import type { FSWatcher, MatchFunction } from 'chokidar';
@@ -17,8 +18,8 @@ type WatchDirReturn = {
 
 export const makeWatchEvents = (
   watcher: FSWatcher,
-  readyResolve: ReturnType<typeof makePromiseKit<CloseWatcher>>['resolve'],
-  throwError: ReturnType<typeof makePromiseKit<never>>['reject'],
+  readyResolve: PromiseKit<CloseWatcher>['resolve'],
+  throwError: PromiseKit<never>['reject'],
   logger: Logger,
 ): {
   ready: () => void;

packages/cli/src/vite/export-metadata-plugin.ts

@@ -0,0 +1,48 @@
+import type { Plugin, RenderedModule } from 'rollup';
+
+export type BundleMetadata = {
+  exports: string[];
+  modules: Record<
+    string,
+    { renderedExports: string[]; removedExports: string[] }
+  >;
+};
+
+/**
+ * Rollup plugin that captures export metadata from the bundle.
+ *
+ * Uses the `generateBundle` hook to extract the exports array and
+ * per-module metadata (renderedExports and removedExports) from the
+ * entry chunk.
+ *
+ * @returns A plugin with an additional `getMetadata()` method.
+ */
+export function exportMetadataPlugin(): Plugin & {
+  getMetadata: () => BundleMetadata;
+} {
+  const metadata: BundleMetadata = { exports: [], modules: {} };
+
+  return {
+    name: 'export-metadata',
+    generateBundle(_, bundle) {
+      for (const chunk of Object.values(bundle)) {
+        if (chunk.type === 'chunk' && chunk.isEntry) {
+          const outputChunk = chunk;
+          metadata.exports = outputChunk.exports;
+          metadata.modules = Object.fromEntries(
+            Object.entries(outputChunk.modules).map(
+              ([id, info]: [string, RenderedModule]) => [
+                id,
+                {
+                  renderedExports: info.renderedExports,
+                  removedExports: info.removedExports,
+                },
+              ],
+            ),
+          );
+        }
+      }
+    },
+    getMetadata: () => metadata,
+  };
+}

packages/cli/src/vite/strip-comments-plugin.test.ts

@@ -0,0 +1,51 @@
+import { describe, it, expect } from 'vitest';
+
+import { stripCommentsPlugin } from './strip-comments-plugin.ts';
+
+describe('stripCommentsPlugin', () => {
+  const plugin = stripCommentsPlugin();
+  const renderChunk = plugin.renderChunk as (code: string) => string | null;
+
+  it.each([
+    [
+      'single-line comment',
+      'const x = 1; // comment\nconst y = 2;',
+      'const x = 1; \nconst y = 2;',
+    ],
+    [
+      'multi-line comment',
+      'const x = 1; /* comment */ const y = 2;',
+      'const x = 1;  const y = 2;',
+    ],
+    [
+      'multiple comments',
+      '/* a */ const x = 1; // b\n/* c */',
+      ' const x = 1; \n',
+    ],
+    [
+      'comment containing import()',
+      'const x = 1; // import("module")\nconst y = 2;',
+      'const x = 1; \nconst y = 2;',
+    ],
+    [
+      'comment with string content preserved',
+      'const x = "// in string"; // real comment',
+      'const x = "// in string"; ',
+    ],
+    ['code that is only a comment', '// just a comment', ''],
+  ])('removes %s', (_name, code, expected) => {
+    expect(renderChunk(code)).toBe(expected);
+  });
+
+  it.each([
+    ['string with // pattern', 'const x = "// not a comment";'],
+    ['string with /* */ pattern', 'const x = "/* not a comment */";'],
+    ['regex literal like //', 'const re = /\\/\\//;'],
+    ['template literal with // pattern', 'const x = `// not a comment`;'],
+    ['nested quotes in string', 'const x = "a \\"// not comment\\" b";'],
+    ['no comments', 'const x = 1;'],
+    ['empty code', ''],
+  ])('returns null for %s', (_name, code) => {
+    expect(renderChunk(code)).toBeNull();
+  });
+});

packages/cli/src/vite/strip-comments-plugin.ts

@@ -0,0 +1,46 @@
+import type { Comment } from 'acorn';
+import { parse } from 'acorn';
+import type { Plugin } from 'rollup';
+
+/**
+ * Rollup plugin that strips comments from bundled code using AST parsing.
+ *
+ * SES rejects code containing `import(` patterns, even when they appear
+ * in comments. This plugin uses Acorn to definitively identify comment nodes
+ * and removes them to avoid triggering that detection.
+ *
+ * Uses the `renderChunk` hook to process the final output.
+ *
+ * @returns A Rollup plugin.
+ */
+export function stripCommentsPlugin(): Plugin {
+  return {
+    name: 'strip-comments',
+    renderChunk(code) {
+      const comments: Comment[] = [];
+
+      parse(code, {
+        ecmaVersion: 'latest',
+        sourceType: 'module',
+        onComment: comments,
+      });
+
+      if (comments.length === 0) {
+        return null;
+      }
+
+      // Build result by copying non-comment ranges.
+      // Comments are sorted by position since acorn parses linearly.
+      let result = '';
+      let position = 0;
+
+      for (const comment of comments) {
+        result += code.slice(position, comment.start);
+        position = comment.end;
+      }
+
+      result += code.slice(position);
+      return result;
+    },
+  };
+}

packages/cli/src/vite/vat-bundler.ts

@@ -0,0 +1,60 @@
+import type { VatBundle } from '@metamask/kernel-utils';
+import { build } from 'vite';
+import type { Rollup, PluginOption } from 'vite';
+
+import { exportMetadataPlugin } from './export-metadata-plugin.ts';
+import { stripCommentsPlugin } from './strip-comments-plugin.ts';
+
+export type { VatBundle };
+
+/**
+ * Bundle a vat source file using vite.
+ *
+ * Produces an IIFE bundle that assigns exports to a `__vatExports__` global,
+ * along with metadata about the bundle's exports and modules.
+ *
+ * @param sourcePath - Absolute path to the vat entry point.
+ * @returns The bundle object containing code and metadata.
+ */
+export async function bundleVat(sourcePath: string): Promise<VatBundle> {
+  const metadataPlugin = exportMetadataPlugin();
+
+  const result = await build({
+    configFile: false,
+    logLevel: 'silent',
+    build: {
+      write: false,
+      lib: {
+        entry: sourcePath,
+        formats: ['iife'],
+        name: '__vatExports__',
+      },
+      rollupOptions: {
+        output: {
+          exports: 'named',
+          inlineDynamicImports: true,
+        },
+        plugins: [
+          stripCommentsPlugin() as unknown as PluginOption,
+          metadataPlugin as unknown as PluginOption,
+        ],
+      },
+      minify: false,
+    },
+  });
+
+  const output = Array.isArray(result) ? result[0] : result;
+  const chunk = (output as Rollup.RollupOutput).output.find(
+    (item): item is Rollup.OutputChunk => item.type === 'chunk' && item.isEntry,
+  );
+
+  if (!chunk) {
+    throw new Error(`Failed to produce bundle for ${sourcePath}`);
+  }
+
+  return {
+    moduleFormat: 'iife',
+    code: chunk.code,
+    ...metadataPlugin.getMetadata(),
+  };
+}