Sequentialize uncaught exceptions in Node.js Workers

src/lib/libpthread.js

@@ -241,6 +241,9 @@ var LibraryPThread = {
       worker.onmessage = (e) => {
         var d = e['data'];
         var cmd = d.cmd;
+#if PTHREADS_DEBUG
+        dbg(`main thread: received message '${cmd}' from worker. ${d}`);
+#endif
 
         // If this message is intended to a recipient that is not the main
         // thread, forward it to the target thread.
@@ -283,6 +286,13 @@ var LibraryPThread = {
           // Worker wants to postMessage() to itself to implement setImmediate()
           // emulation.
           worker.postMessage(d);
+#if ENVIRONMENT_MAY_BE_NODE
+        } else if (cmd === 'uncaughtException') {
+          // Message handler for Node.js specific out-of-order behavior:
+          // https://github.com/nodejs/node/issues/59617
+          // A pthread sent an uncaught exception event. Re-raise it on the main thread.
+          worker.onerror(d.error);
+#endif
         } else if (cmd === 'callHandler') {
           Module[d.handler](...d.args);
         } else if (cmd) {
@@ -308,6 +318,13 @@ var LibraryPThread = {
       if (ENVIRONMENT_IS_NODE) {
         worker.on('message', (data) => worker.onmessage({ data: data }));
         worker.on('error', (e) => worker.onerror(e));
+
+#if PTHREADS_DEBUG
+        worker.on('exit', (code) => {
+          if (worker.pthread_ptr) dbg(`Worker hosting pthread ${ptrToString(worker.pthread_ptr)} has terminated with code ${code}.`);
+          else dbg(`Worker has terminated with code ${code}.`);
+        });
+#endif
       }
 #endif
 

src/runtime_common.js

@@ -40,6 +40,21 @@ if (ENVIRONMENT_IS_NODE && {{{ ENVIRONMENT_IS_WORKER_THREAD() }}}) {
     self: global,
     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
+  // To remedy this, capture all uncaughtExceptions in the Worker, and sequentialize those over
+  // to the same postMessage pipe that other messages use.
+  process.on("uncaughtException", (err) => {
+#if PTHREADS_DEBUG
+    dbg(`uncaughtException on worker thread: ${err.message}`);
+#endif
+    postMessage({ cmd: 'uncaughtException', error: err });
+    // Also shut down the Worker to match the same semantics as if this uncaughtException
+    // handler was not registered.
+    // (n.b. this will not shut down the whole Node.js app process, but just the Worker)
+    process.exit(1);
+  });
 }
 #endif // (PTHREADS || WASM_WORKERS) && (ENVIRONMENT_MAY_BE_NODE && !WASM_ESM_INTEGRATION)
 

test/code_size/test_codesize_minimal_pthreads.json

@@ -1,10 +1,10 @@
 {
-  "a.out.js": 7499,
-  "a.out.js.gz": 3721,
+  "a.out.js": 7649,
+  "a.out.js.gz": 3768,
   "a.out.nodebug.wasm": 19588,
   "a.out.nodebug.wasm.gz": 9025,
-  "total": 27087,
-  "total_gz": 12746,
+  "total": 27237,
+  "total_gz": 12793,
   "sent": [
     "a (memory)",
     "b (emscripten_get_now)",

test/code_size/test_codesize_minimal_pthreads_memgrowth.json

@@ -1,10 +1,10 @@
 {
-  "a.out.js": 7926,
-  "a.out.js.gz": 3924,
+  "a.out.js": 8076,
+  "a.out.js.gz": 3974,
   "a.out.nodebug.wasm": 19589,
   "a.out.nodebug.wasm.gz": 9025,
-  "total": 27515,
-  "total_gz": 12949,
+  "total": 27665,
+  "total_gz": 12999,
   "sent": [
     "a (memory)",
     "b (emscripten_get_now)",

test/test_core.py

@@ -24,7 +24,7 @@
 from tools import shared, building, config, utils, webassembly
 import common
 from common import RunnerCore, path_from_root, requires_native_clang, test_file, create_file
-from common import skip_if, no_windows, no_mac, is_slow_test, parameterized, parameterize
+from common import skip_if, no_windows, is_slow_test, parameterized, parameterize
 from common import env_modify, with_env_modify, disabled, flaky, node_pthreads, also_without_bigint
 from common import read_file, read_binary, requires_v8, requires_node, requires_dev_dependency, requires_wasm2js, requires_node_canary
 from common import compiler_for, crossplatform, no_4gb, no_2gb, also_with_minimal_runtime, also_with_modularize
@@ -2669,8 +2669,6 @@ def test_pthread_attr_getstack(self):
     self.do_run_in_out_file_test('pthread/test_pthread_attr_getstack.c')
 
   @node_pthreads
-  @no_mac('https://github.com/emscripten-core/emscripten/issues/15014')
-  @flaky('https://github.com/emscripten-core/emscripten/issues/15014')
   def test_pthread_abort(self):
     self.set_setting('PROXY_TO_PTHREAD')
     # Add the onAbort handler at runtime during preRun.  This means that onAbort