Avoid proxying print handlers back to the main thread

This partially reverts commit 97b352e.

Resolves: #19683.

Author: kleisauke

src/lib/libpthread.js

@@ -344,12 +344,6 @@ var LibraryPThread = {
 #endif
 #if expectToReceiveOnModule('onAbort')
         'onAbort',
-#endif
-#if expectToReceiveOnModule('print')
-        'print',
-#endif
-#if expectToReceiveOnModule('printErr')
-        'printErr',
 #endif
       ];
       for (var handler of knownHandlers) {

src/runtime_pthread.js

@@ -82,7 +82,7 @@ if (ENVIRONMENT_IS_PTHREAD) {
         // Use `const` here to ensure that the variable is scoped only to
         // that iteration, allowing safe reference from a closure.
         for (const handler of msgData.handlers) {
-          // The the main module has a handler for a certain even, but no
+          // The main module has a handler for a certain event, but no
           // handler exists on the pthread worker, then proxy that handler
           // back to the main thread.
           if (!Module[handler] || Module[handler].proxy) {
@@ -95,9 +95,6 @@ if (ENVIRONMENT_IS_PTHREAD) {
 #endif
               postMessage({ cmd: 'callHandler', handler, args: args });
             }
-            // Rebind the out / err handlers if needed
-            if (handler == 'print') out = Module[handler];
-            if (handler == 'printErr') err = Module[handler];
           }
 #if RUNTIME_DEBUG
           else dbg(`worker: using thread-local handler: ${handler}`);

test/test_other.py

@@ -7235,42 +7235,6 @@ def test_modularize_instantiation_error(self):
     self.assertContained('failed to asynchronously prepare wasm', output)
     self.assertContained('got error: RuntimeError: Aborted', output)
 
-  @crossplatform
-  @node_pthreads
-  @flaky('https://github.com/emscripten-core/emscripten/issues/19683')
-  # The flakiness of this test is very high on macOS so just disable it
-  # completely.
-  @no_mac('https://github.com/emscripten-core/emscripten/issues/19683')
-  def test_pthread_print_override_modularize(self):
-    self.set_setting('EXPORT_NAME', 'Test')
-    self.set_setting('PROXY_TO_PTHREAD')
-    self.set_setting('EXIT_RUNTIME')
-    self.set_setting('MODULARIZE')
-    create_file('main.c', '''
-      #include <emscripten/console.h>
-
-      int main() {
-        emscripten_out("hello, world!");
-        return 0;
-      }
-    ''')
-    create_file('main.js', '''
-      const Test = require('./test.js');
-
-      async function main() {
-        await Test({
-          // world -> earth
-          print: (text) => console.log(text.replace('world', 'earth'))
-        });
-      }
-      main();
-    ''')
-
-    self.emcc('main.c', output_filename='test.js')
-    output = self.run_js('main.js')
-    self.assertNotContained('hello, world!', output)
-    self.assertContained('hello, earth!', output)
-
   def test_define_modularize(self):
     self.run_process([EMCC, test_file('hello_world.c'), '-sMODULARIZE', '-sASSERTIONS=0'])
     src = 'var module = 0; ' + read_file('a.out.js')