Ignore EXPORT_NAME in EXPORT_ES6 mode. NFC (#24138)

The internal name of the factory function is not exposed to the outside
world in `EXPORT_ES6` mode, so there is no point in setting this
setting.

Author: sbc100

.circleci/config.yml

@@ -730,8 +730,7 @@ jobs:
       - run-tests:
           test_targets: "
             core0.test_hello_argc
-            other.test_modularize_incoming
-            other.test_modularize_incoming_export_name"
+            other.test_modularize_incoming*"
   test-spidermonkey:
     executor: linux-python
     steps:

src/wasm_worker.js

@@ -71,7 +71,7 @@ if (ENVIRONMENT_IS_NODE) {
 #endif
   importScripts(d.js);
 #if MODULARIZE
-  {{{ EXPORT_NAME }}}(d);
+  {{{ EXPORT_ES6 ? 'moduleFactory' : EXPORT_NAME }}}(d);
 #endif
   // Drop now unneeded references to from the Module object in this Worker,
   // these are not needed anymore.

test/modularize_post_js.js

@@ -7,4 +7,8 @@
 // Avoid instantiating the module on pthreads.
 if (!isPthread)
 #endif
+#if EXPORT_ES6
+moduleFactory();
+#else
 {{{ EXPORT_NAME }}}();
+#endif

test/other/codesize/test_codesize_minimal_esm.gzsize

@@ -1 +1 @@
-1298
+1301

test/other/codesize/test_codesize_minimal_esm.jssize

@@ -1 +1 @@
-2697
+2711

test/test_other.py

@@ -355,7 +355,7 @@ def test_esm(self, args):
     self.run_process([EMCC, '-o', 'hello_world.mjs',
                       '--extern-post-js', test_file('modularize_post_js.js'),
                       test_file('hello_world.c')] + args)
-    self.assertContained('export default Module;', read_file('hello_world.mjs'))
+    self.assertContained('export default moduleFactory;', read_file('hello_world.mjs'))
     self.assertContained('hello, world!', self.run_js('hello_world.mjs'))
 
   @requires_node_canary
@@ -381,7 +381,7 @@ def test_esm_worker(self, args):
     src = read_file('subdir/hello_world.mjs')
     self.assertContained("new URL('hello_world.wasm', import.meta.url)", src)
     self.assertContained("new Worker(new URL('hello_world.mjs', import.meta.url), {", src)
-    self.assertContained('export default Module;', src)
+    self.assertContained('export default moduleFactory;', src)
     self.assertContained('hello, world!', self.run_js('subdir/hello_world.mjs'))
 
   @node_pthreads
@@ -405,12 +405,16 @@ def test_esm_closure(self):
   def test_esm_implies_modularize(self):
     self.run_process([EMCC, test_file('hello_world.c'), '-sEXPORT_ES6'])
     src = read_file('a.out.js')
-    self.assertContained('export default Module;', src)
+    self.assertContained('export default moduleFactory;', src)
 
   def test_esm_requires_modularize(self):
     err = self.expect_fail([EMCC, test_file('hello_world.c'), '-sEXPORT_ES6', '-sMODULARIZE=0'])
     self.assertContained('EXPORT_ES6 requires MODULARIZE to be set', err)
 
+  def test_esm_ignore_export_name(self):
+    err = self.expect_fail([EMCC, test_file('hello_world.c'), '-sEXPORT_ES6', '-sEXPORT_NAME=Foo', '-Werror'])
+    self.assertContained('emcc: error: EXPORT_NAME is not used in EXPORT_ES6 mode [-Wunused-command-line-argument] [-Werror]', err)
+
   def test_emcc_out_file(self):
     # Verify that "-ofile" works in addition to "-o" "file"
     self.run_process([EMCC, '-c', '-ofoo.o', test_file('hello_world.c')])
@@ -7058,8 +7062,7 @@ def test_modularize_new_misuse(self):
 
   @parameterized({
     '': ([],),
-    'export_name': (['-sEXPORT_NAME=Foo'],),
-    'closure': (['-sEXPORT_NAME=Foo', '--closure=1'],),
+    'closure': (['--closure=1'],),
   })
   @crossplatform
   def test_modularize_incoming(self, args):
@@ -11160,6 +11163,7 @@ def test_node_js_pthread_module(self, es6):
         ''')
     else:
       ext = '.js'
+      self.emcc_args += ['-sMODULARIZE', '-sEXPORT_NAME=test_module']
       create_file('moduleLoader.js', '''
         const test_module = require("./subdir/module.js");
         test_module().then((test_module_instance) => {
@@ -11169,7 +11173,7 @@ def test_node_js_pthread_module(self, es6):
     ensure_dir('subdir')
 
     # build hello_world.c
-    self.run_process([EMCC, test_file('hello_world.c'), '-o', 'subdir/module' + ext, '-pthread', '-sPTHREAD_POOL_SIZE=2', '-sMODULARIZE', '-sEXPORT_NAME=test_module'] + self.get_emcc_args())
+    self.run_process([EMCC, test_file('hello_world.c'), '-o', 'subdir/module' + ext, '-pthread', '-sPTHREAD_POOL_SIZE=2'] + self.get_emcc_args())
 
     # run the module
     ret = self.run_js('moduleLoader' + ext)

tools/link.py

@@ -1796,6 +1796,10 @@ def get_full_import_name(name):
   if not js_manipulation.isidentifier(settings.EXPORT_NAME):
     exit_with_error(f'EXPORT_NAME is not a valid JS identifier: `{settings.EXPORT_NAME}`')
 
+  if settings.EXPORT_ES6 and 'EXPORT_NAME' in user_settings:
+    diagnostics.warning('unused-command-line-argument', 'EXPORT_NAME is not used in EXPORT_ES6 mode')
+    settings.EXPORT_NAME = None
+
   if settings.EMSCRIPTEN_TRACING:
     add_system_js_lib('libtrace.js')
     if settings.ALLOW_MEMORY_GROWTH:
@@ -2464,11 +2468,15 @@ def modularize():
       'maybe_async': maybe_async,
       'generated_js': generated_js
     }
+  if settings.EXPORT_ES6:
+    factory_name = 'moduleFactory'
+  else:
+    factory_name = settings.EXPORT_NAME
 
   if settings.MINIMAL_RUNTIME and not settings.PTHREADS:
     # Single threaded MINIMAL_RUNTIME programs do not need access to
     # document.currentScript, so a simple export declaration is enough.
-    src = f'var {settings.EXPORT_NAME} = {wrapper_function};'
+    src = f'var {factory_name} = {wrapper_function};'
   else:
     script_url_web = ''
     # When MODULARIZE this JS may be executed later,
@@ -2477,12 +2485,12 @@ def modularize():
     if settings.ENVIRONMENT_MAY_BE_WEB and not settings.EXPORT_ES6:
        script_url_web = "var _scriptName = typeof document != 'undefined' ? document.currentScript?.src : undefined;"
     src = '''\
-var %(EXPORT_NAME)s = (() => {
+var %(factory_name)s = (() => {
   %(script_url_web)s
   return (%(wrapper_function)s);
 })();
 ''' % {
-      'EXPORT_NAME': settings.EXPORT_NAME,
+      'factory_name': factory_name,
       'script_url_web': script_url_web,
       'wrapper_function': wrapper_function,
     }
@@ -2497,11 +2505,11 @@ def modularize():
   # Module variable name. This should happen even in MINIMAL_RUNTIME builds
   # for MODULARIZE and EXPORT_ES6 to work correctly.
   if settings.AUDIO_WORKLET:
-    src += f'globalThis.AudioWorkletModule = {settings.EXPORT_NAME};\n'
+    src += f'globalThis.AudioWorkletModule = {factory_name};\n'
 
   # Export using a UMD style export, or ES6 exports if selected
   if settings.EXPORT_ES6:
-    src += 'export default %s;\n' % settings.EXPORT_NAME
+    src += 'export default moduleFactory;\n'
   elif not settings.MINIMAL_RUNTIME:
     src += '''\
 if (typeof exports === 'object' && typeof module === 'object') {
@@ -2530,7 +2538,7 @@ def modularize():
     if settings.MODULARIZE == 'instance':
       src += 'isPthread && init();\n'
     else:
-      src += 'isPthread && %s();\n' % settings.EXPORT_NAME
+      src += f'isPthread && {factory_name}();\n'
 
   final_js += '.modular.js'
   write_file(final_js, src)