Fix multithreading support for Deno and Bun

Fixes denoland/deno#17171

Also adds several pthread tests with Bun and Deno

Author: Macil

.circleci/config.yml

@@ -883,7 +883,34 @@ jobs:
             echo "BUN_ENGINE = os.path.expanduser('~/.bun/bin/bun')" >> ~/emsdk/.emscripten
             echo "JS_ENGINES = [BUN_ENGINE]" >> ~/emsdk/.emscripten
       - run-tests:
-          test_targets: "core0.test_hello_world"
+          test_targets: "
+            core0.test_hello_world
+            core0.test_hello_argc_pthreads
+            core2.test_pthread_create
+            core2.test_pthread_unhandledrejection
+            "
+  test-deno:
+    executor: linux-python
+    steps:
+      - checkout
+      - pip-install
+      - install-emsdk
+      - run:
+          name: install deno
+          command: |
+            curl -fsSL https://deno.land/install.sh | sh
+            echo "DENO_ENGINE = [os.path.expanduser('~/.deno/bin/deno'), 'run', '--allow-read', '--unstable-detect-cjs']" >> ~/emsdk/.emscripten
+            echo "JS_ENGINES = [DENO_ENGINE]" >> ~/emsdk/.emscripten
+      - run-tests:
+          test_targets: "
+            core0.test_hello_world
+            core0.test_asyncify_main_module
+            core2.test_pthread_create
+            core2.test_pthread_unhandledrejection
+            "
+            # The following tests using PROXY_TO_PTHREAD are disabled because of https://github.com/denoland/deno/issues/14786:
+            # core0.test_hello_argc_pthreads
+            # core0.test_pthread_join_and_asyncify
   test-jsc:
     executor: linux-python
     steps:
@@ -1377,6 +1404,7 @@ workflows:
           requires:
             - build-linux
       - test-bun
+      - test-deno
       - test-jsc
       - test-spidermonkey
       - test-node-compat

src/pthread_esm_startup.mjs

@@ -15,14 +15,17 @@ console.log("Running pthread_esm_startup");
 
 #if ENVIRONMENT_MAY_BE_NODE
 // Create as web-worker-like an environment as we can.
-var worker_threads = await import('worker_threads');
-global.Worker = worker_threads.Worker;
-var parentPort = worker_threads['parentPort'];
-parentPort.on('message', (msg) => global.onmessage?.({ data: msg }));
-Object.assign(globalThis, {
-  self: global,
-  postMessage: (msg) => parentPort['postMessage'](msg),
-});
+globalThis.self = globalThis;
+// Deno and Bun already have `postMessage` defined on the global scope and
+// deliver messages to `globalThis.onmessage`, so we must not duplicate that
+// behavior here if `postMessage` is already present.
+if (!globalThis.postMessage) {
+  const worker_threads = await import('worker_threads');
+  globalThis.Worker = worker_threads.Worker;
+  const parentPort = worker_threads['parentPort'];
+  parentPort.on('message', (msg) => globalThis.onmessage?.({ data: msg }));
+  globalThis.postMessage = (msg) => parentPort['postMessage'](msg);
+}
 #endif
 
 self.onmessage = async (msg) => {

src/runtime_common.js

@@ -38,12 +38,15 @@ var readyPromiseResolve, readyPromiseReject;
 #if (PTHREADS || WASM_WORKERS) && (ENVIRONMENT_MAY_BE_NODE && !WASM_ESM_INTEGRATION)
 if (ENVIRONMENT_IS_NODE && {{{ ENVIRONMENT_IS_WORKER_THREAD() }}}) {
   // Create as web-worker-like an environment as we can.
-  var parentPort = worker_threads['parentPort'];
-  parentPort.on('message', (msg) => global.onmessage?.({ data: msg }));
-  Object.assign(globalThis, {
-    self: global,
-    postMessage: (msg) => parentPort['postMessage'](msg),
-  });
+  globalThis.self = globalThis;
+  // Deno and Bun already have `postMessage` defined on the global scope and
+  // deliver messages to `globalThis.onmessage`, so we must not duplicate that
+  // behavior here if `postMessage` is already present.
+  if (!globalThis.postMessage) {
+    const parentPort = worker_threads['parentPort'];
+    parentPort.on('message', (msg) => globalThis.onmessage?.({ data: msg }));
+    globalThis.postMessage = (msg) => parentPort['postMessage'](msg);
+  }
   // Node.js Workers do not pass postMessage()s and uncaught exception events to the parent
   // thread necessarily in the same order where they were generated in sequential program order.
   // See https://github.com/nodejs/node/issues/59617

src/wasm_worker.js

@@ -57,6 +57,7 @@ if (ENVIRONMENT_IS_NODE) {
     return f;
   }
 
+  const parentPort = worker_threads['parentPort'];
   Object.assign(globalThis, {
     addEventListener: (name, handler) => parentPort['on'](name, wrapMsgHandler(handler)),
     removeEventListener: (name, handler) => parentPort['off'](name, wrapMsgHandler(handler)),

test/common.py

@@ -393,6 +393,31 @@ def require_node(self):
     self.require_engine(nodejs)
     return nodejs
 
+  def get_deno(self):
+    """Return deno engine, if one is configured, otherwise None"""
+    if config.DENO_ENGINE and config.DENO_ENGINE in config.JS_ENGINES:
+      return config.DENO_ENGINE
+    return None
+
+  def get_node_bun_or_deno(self):
+    """Return nodejs, bun, or deno engine, if one is configured, otherwise None"""
+    if config.NODE_JS_TEST in config.JS_ENGINES:
+      return config.NODE_JS_TEST
+    if config.BUN_ENGINE and config.BUN_ENGINE in config.JS_ENGINES:
+      return config.BUN_ENGINE
+    if config.DENO_ENGINE and config.DENO_ENGINE in config.JS_ENGINES:
+      return config.DENO_ENGINE
+    return None
+
+  def require_node_bun_or_deno(self):
+    if 'EMTEST_SKIP_NODE' in os.environ:
+      self.skipTest('test requires node, bun, or deno and EMTEST_SKIP_NODE is set')
+    engine = self.get_node_bun_or_deno()
+    if not engine:
+      self.fail('node, bun, or deno required to run this test.  Use EMTEST_SKIP_NODE to skip')
+    self.require_engine(engine)
+    return engine
+
   def node_is_canary(self, nodejs):
     return nodejs and nodejs[0] and ('canary' in nodejs[0] or 'nightly' in nodejs[0])
 
@@ -406,6 +431,20 @@ def require_node_canary(self):
 
     self.fail('node canary required to run this test.  Use EMTEST_SKIP_NODE_CANARY to skip')
 
+  def require_node_canary_or_deno(self):
+    if 'EMTEST_SKIP_NODE_CANARY' in os.environ:
+      self.skipTest('test requires node canary or deno and EMTEST_SKIP_NODE_CANARY is set')
+    nodejs = self.get_nodejs()
+    if self.node_is_canary(nodejs):
+      self.require_engine(nodejs)
+      return
+    deno = self.get_deno()
+    if deno:
+      self.require_engine(deno)
+      return
+
+    self.fail('node canary or deno required to run this test.  Use EMTEST_SKIP_NODE_CANARY to skip')
+
   def require_engine(self, engine):
     logger.debug(f'require_engine: {engine}')
     if self.required_engine and self.required_engine != engine:
@@ -517,9 +556,16 @@ def require_jspi(self):
       return
 
     exp_args = ['--experimental-wasm-stack-switching', '--experimental-wasm-type-reflection']
-    # Support for JSPI came earlier than 22, but the new API changes require v24
-    if self.try_require_node_version(24):
-      self.node_args += exp_args
+    nodejs = self.get_nodejs()
+    if nodejs:
+      # Support for JSPI came earlier than 22, but the new API changes require v24
+      if self.try_require_node_version(24):
+        self.node_args += exp_args
+        return
+
+    deno = self.get_deno()
+    if deno:
+      self.js_engines = [deno]
       return
 
     v8 = self.get_v8()
@@ -529,7 +575,7 @@ def require_jspi(self):
       self.v8_args += exp_args
       return
 
-    self.fail('either d8 or node v24 required to run JSPI tests.  Use EMTEST_SKIP_JSPI to skip')
+    self.fail('either d8, node v24, or deno required to run JSPI tests.  Use EMTEST_SKIP_JSPI to skip')
 
   def require_wasm2js(self):
     if self.is_wasm64():
@@ -556,13 +602,15 @@ def setup_wasmfs_test(self):
     self.cflags += ['-DWASMFS']
 
   def setup_node_pthreads(self):
-    self.require_node()
+    self.require_node_bun_or_deno()
     self.cflags += ['-Wno-pthreads-mem-growth', '-pthread']
     if self.get_setting('MINIMAL_RUNTIME'):
       self.skipTest('node pthreads not yet supported with MINIMAL_RUNTIME')
+    engine = self.get_node_bun_or_deno()
+    self.js_engines = [engine]
     nodejs = self.get_nodejs()
-    self.js_engines = [nodejs]
-    self.node_args += shared.node_pthread_flags(nodejs)
+    if nodejs:
+      self.node_args += shared.node_pthread_flags(engine)
 
   def set_temp_dir(self, temp_dir):
     self.temp_dir = temp_dir

test/decorators.py

@@ -140,6 +140,17 @@ def decorated(self, *args, **kwargs):
   return decorated
 
 
+def requires_node_canary_or_deno(func):
+  assert callable(func)
+
+  @wraps(func)
+  def decorated(self, *args, **kwargs):
+    self.require_node_canary_or_deno()
+    return func(self, *args, **kwargs)
+
+  return decorated
+
+
 # Used to mark dependencies in various tests to npm developer dependency
 # packages, which might not be installed on Emscripten end users' systems.
 def requires_dev_dependency(package):

test/pthread/test_pthread_unhandledrejection.c

@@ -1,6 +1,6 @@
 #include <emscripten/emscripten.h>
 
 int main() {
-  EM_ASM({ Promise.reject("rejected!"); });
+  EM_ASM({ Promise.reject(new Error("rejected!")); });
   emscripten_exit_with_live_runtime();
 }

test/test_browser.py

@@ -5401,7 +5401,7 @@ def test_pthread_unhandledrejection(self):
                cflags=['-pthread', '-sPROXY_TO_PTHREAD', '--post-js',
                           test_file('pthread/test_pthread_unhandledrejection.post.js')],
                # Firefox and Chrome report this slightly differently
-               expected=['exception:Uncaught rejected!', 'exception:uncaught exception: rejected!'])
+               expected=['exception:Error: rejected!', 'exception:Uncaught Error: rejected!'])
 
   def test_pthread_key_recreation(self):
     self.btest_exit('pthread/test_pthread_key_recreation.c', cflags=['-pthread', '-sPTHREAD_POOL_SIZE=1'])

test/test_core.py

@@ -60,7 +60,7 @@
   requires_jspi,
   requires_native_clang,
   requires_node,
-  requires_node_canary,
+  requires_node_canary_or_deno,
   requires_v8,
   requires_wasm2js,
   requires_wasm_eh,
@@ -8502,7 +8502,7 @@ def test_asyncify_main_module(self):
     self.do_core_test('test_hello_world.c')
 
   # Test that pthread_join works correctly with asyncify.
-  @requires_node_canary
+  @requires_node_canary_or_deno
   @node_pthreads
   def test_pthread_join_and_asyncify(self):
     # TODO Test with ASYNCIFY=1 https://github.com/emscripten-core/emscripten/issues/17552

tools/config.py

@@ -19,6 +19,8 @@
 # See parse_config_file below.
 EMSCRIPTEN_ROOT = __rootpath__
 NODE_JS = None
+BUN_ENGINE = None
+DENO_ENGINE = None
 BINARYEN_ROOT = None
 LLVM_ADD_VERSION = None
 CLANG_ADD_VERSION = None
@@ -59,11 +61,13 @@ def fix_js_engine(old, new):
 
 def normalize_config_settings():
   global CACHE, PORTS, LLVM_ADD_VERSION, CLANG_ADD_VERSION, CLOSURE_COMPILER
-  global NODE_JS, NODE_JS_TEST, V8_ENGINE, JS_ENGINES, SPIDERMONKEY_ENGINE, WASM_ENGINES
+  global NODE_JS, NODE_JS_TEST, BUN_ENGINE, DENO_ENGINE, V8_ENGINE, JS_ENGINES, SPIDERMONKEY_ENGINE, WASM_ENGINES
 
   SPIDERMONKEY_ENGINE = fix_js_engine(SPIDERMONKEY_ENGINE, listify(SPIDERMONKEY_ENGINE))
   NODE_JS = fix_js_engine(NODE_JS, listify(NODE_JS))
   NODE_JS_TEST = fix_js_engine(NODE_JS_TEST, listify(NODE_JS_TEST))
+  BUN_ENGINE = fix_js_engine(BUN_ENGINE, listify(BUN_ENGINE))
+  DENO_ENGINE = fix_js_engine(DENO_ENGINE, listify(DENO_ENGINE))
   V8_ENGINE = fix_js_engine(V8_ENGINE, listify(V8_ENGINE))
   JS_ENGINES = [listify(engine) for engine in JS_ENGINES]
   WASM_ENGINES = [listify(engine) for engine in WASM_ENGINES]
@@ -102,6 +106,8 @@ def parse_config_file():
   CONFIG_KEYS = (
     'NODE_JS',
     'NODE_JS_TEST',
+    'BUN_ENGINE',
+    'DENO_ENGINE',
     'BINARYEN_ROOT',
     'SPIDERMONKEY_ENGINE',
     'V8_ENGINE',