fix(sea): parse ESM files as modules and walk dynamic import() literals

`detector.parse()` called babel with the default `sourceType: 'script'`,
so SEA-mode walker runs over `import.meta` / top-level `await` failed
to parse and silently skipped the file's dependency traversal. Thread
`isESMFile(record.file)` through `stepDetect` → `detect()` → `parse()`
so ESM files get `sourceType: 'module'`. Also teach the visitor to
recognize `import('literal')` `CallExpression`s so bundler-emitted
dynamic imports are bundled like static ones.

Author: robertsLando

lib/detector.ts

@@ -181,6 +181,22 @@ function visitorImport(n: babelTypes.Node) {
   return { v1: n.source.value, v3: reconstructSpecifiers(n.specifiers) };
 }
 
+function visitorDynamicImport(n: babelTypes.Node) {
+  if (!babelTypes.isCallExpression(n)) {
+    return null;
+  }
+
+  if (n.callee.type !== 'Import') {
+    return null;
+  }
+
+  if (!n.arguments || !isLiteral(n.arguments[0])) {
+    return null;
+  }
+
+  return { v1: getLiteralValue(n.arguments[0] as babelTypes.Literal) };
+}
+
 function visitorPathJoin(n: babelTypes.Node) {
   if (!babelTypes.isCallExpression(n)) {
     return null;
@@ -270,6 +286,16 @@ export function visitorSuccessful(node: babelTypes.Node, test = false) {
     return { alias: was.v1, aliasType: ALIAS_AS_RESOLVABLE };
   }
 
+  was = visitorDynamicImport(node);
+
+  if (was) {
+    if (test) {
+      return forge('import({v1})', was);
+    }
+
+    return { alias: was.v1, aliasType: ALIAS_AS_RESOLVABLE };
+  }
+
   was = visitorPathJoin(node);
 
   if (was) {
@@ -495,18 +521,24 @@ function traverse(ast: babelTypes.File, visitor: VisitorFunction) {
   }
 }
 
-export function parse(body: string) {
+export function parse(body: string, isEsm = false) {
   return babel.parse(body, {
     allowImportExportEverywhere: true,
     allowReturnOutsideFunction: true,
+    sourceType: isEsm ? 'module' : 'script',
   });
 }
 
-export function detect(body: string, visitor: VisitorFunction, file?: string) {
+export function detect(
+  body: string,
+  visitor: VisitorFunction,
+  file?: string,
+  isEsm = false,
+) {
   let json;
 
   try {
-    json = parse(body);
+    json = parse(body, isEsm);
   } catch (error) {
     const fileInfo = file ? ` in ${file}` : '';
     log.warn(`Babel parse has failed: ${(error as Error).message}${fileInfo}`);

lib/walker.ts

@@ -325,6 +325,7 @@ function stepDetect(
         return true; // can i go inside?
       },
       record.file,
+      isESMFile(record.file),
     );
   } catch (error) {
     log.error((error as Error).message, record.file);

test/test-94-sea-esm-import-meta/app/index.mjs

@@ -0,0 +1,12 @@
+// `import.meta` is only valid in `sourceType: "module"`. Before the fix for
+// issue #264 the SEA walker parsed this body in script mode, so the parse
+// failed and the detector never saw the imports below — neither the static
+// one nor the dynamic one ended up in the snapshot.
+import { greet } from './lib/helper.mjs';
+
+const here = new URL(import.meta.url).pathname;
+console.log('here:' + here.split('/').pop());
+console.log('static:' + greet('world'));
+
+const dyn = await import('./lib/dyn.mjs');
+console.log('dynamic:' + dyn.shout('world'));

test/test-94-sea-esm-import-meta/app/lib/dyn.mjs

@@ -0,0 +1,3 @@
+export function shout(name) {
+  return 'HELLO ' + name.toUpperCase();
+}

test/test-94-sea-esm-import-meta/app/lib/helper.mjs

@@ -0,0 +1,3 @@
+export function greet(name) {
+  return 'hello ' + name;
+}

test/test-94-sea-esm-import-meta/app/package.json

@@ -0,0 +1,7 @@
+{
+  "name": "test-94-sea-esm-import-meta",
+  "version": "1.0.0",
+  "type": "module",
+  "main": "index.mjs",
+  "bin": "index.mjs"
+}

test/test-94-sea-esm-import-meta/main.js

@@ -0,0 +1,52 @@
+#!/usr/bin/env node
+
+'use strict';
+
+const assert = require('assert');
+const utils = require('../utils.js');
+
+// Enhanced SEA requires Node.js >= 22
+if (utils.getNodeMajorVersion() < 22) {
+  return;
+}
+
+assert(__dirname === process.cwd());
+
+const input = './app/package.json';
+const testName = 'test-94-sea-esm-import-meta';
+
+const SEA_PLATFORM_SUFFIX = {
+  linux: 'linux',
+  darwin: 'macos',
+  win32: 'win.exe',
+};
+const suffix = SEA_PLATFORM_SUFFIX[process.platform];
+
+const newcomers = utils.seaHostOutputs(testName);
+const before = utils.filesBefore(newcomers);
+
+// Capture pkg's output so we can assert the Babel parse warning (issue #264)
+// never surfaces when walking ESM files that use `import.meta`.
+const args = suffix
+  ? [input, '--sea', '--target', 'host', '--output', `${testName}-${suffix}`]
+  : [input, '--sea'];
+
+const build = utils.pkg.sync(args, { stdio: ['pipe', 'pipe', 'pipe'] });
+const buildLog = build.stdout + build.stderr;
+
+assert(
+  buildLog.indexOf('Babel parse has failed') === -1,
+  'pkg must parse ESM files as modules (issue #264)\npkg output was:\n' +
+    buildLog,
+);
+
+// A successful parse means both imports were walked and bundled — running the
+// binary proves it by printing the imported values. Skip on unsupported hosts.
+if (suffix) {
+  utils.assertSeaOutput(
+    testName,
+    'here:index.mjs\nstatic:hello world\ndynamic:HELLO WORLD\n',
+  );
+}
+
+utils.filesAfter(before, newcomers, { tolerateWindowsEbusy: true });

test/test.js

@@ -84,6 +84,7 @@ const npmTests = [
   'test-90-sea-worker-threads',
   'test-91-sea-esm-entry',
   'test-92-sea-tla',
+  'test-94-sea-esm-import-meta',
 ];
 
 if (testFilter) {