From b81bba552c1e6bf87c0ba7a64df3cd67eff1e2f5 Mon Sep 17 00:00:00 2001
From: Sam Clegg <sbc@chromium.org>
Date: Mon, 16 Dec 2024 15:04:53 -0800
Subject: [PATCH] Don't inject assertions onto the ready promise (#23176)

This is a debug feature that means users who did not await the promise
and tried to access stuff directly on it would see a nice error message.

However with the advent of more usage of async/await, for example in
\#23157 it is not always the ready promise that gets returned to the
user but a language-generated promise from an `await` call.

We could try to jump through more hoops to continue to support this
debug feature, but I don't think added complexity in the toolchain or
the generated code would be worth it.

Split out from #23157.
---
 src/parseTools.mjs   | 29 -----------------------------
 src/shell.js         |  3 ---
 src/shell_minimal.js |  3 ---
 test/test_other.py   | 25 -------------------------
 4 files changed, 60 deletions(-)

diff --git a/src/parseTools.mjs b/src/parseTools.mjs
index fa6da8556e314..375b4bdae45c6 100644
--- a/src/parseTools.mjs
+++ b/src/parseTools.mjs
@@ -971,34 +971,6 @@ function to64(x) {
   return `BigInt(${x})`;
 }
 
-// Add assertions to catch common errors when using the Promise object we
-// return from MODULARIZE Module() invocations.
-function addReadyPromiseAssertions() {
-  // Warn on someone doing
-  //
-  //  var instance = Module();
-  //  ...
-  //  instance._main();
-  const properties = Array.from(EXPORTED_FUNCTIONS.values());
-  // Also warn on onRuntimeInitialized which might be a common pattern with
-  // older MODULARIZE-using codebases.
-  properties.push('onRuntimeInitialized');
-  const warningEnding =
-    ' on the Promise object, instead of the instance. Use .then() to get called back with the instance, see the MODULARIZE docs in src/settings.js';
-  const res = JSON.stringify(properties);
-  return (
-    res +
-    `.forEach((prop) => {
-  if (!Object.getOwnPropertyDescriptor(readyPromise, prop)) {
-    Object.defineProperty(readyPromise, prop, {
-      get: () => abort('You are getting ' + prop + '${warningEnding}'),
-      set: () => abort('You are setting ' + prop + '${warningEnding}'),
-    });
-  }
-});`
-  );
-}
-
 function asyncIf(condition) {
   return condition ? 'async' : '';
 }
@@ -1118,7 +1090,6 @@ addToCompileTimeContext({
   ENVIRONMENT_IS_WORKER_THREAD,
   addAtExit,
   addAtInit,
-  addReadyPromiseAssertions,
   asyncIf,
   awaitIf,
   buildStringArray,
diff --git a/src/shell.js b/src/shell.js
index b799095e8ebd1..36d9e9a4b042f 100644
--- a/src/shell.js
+++ b/src/shell.js
@@ -47,9 +47,6 @@ var readyPromise = new Promise((resolve, reject) => {
   readyPromiseResolve = resolve;
   readyPromiseReject = reject;
 });
-#if ASSERTIONS
-{{{ addReadyPromiseAssertions() }}}
-#endif
 #endif
 
 // Determine the runtime environment we are in. You can customize this by
diff --git a/src/shell_minimal.js b/src/shell_minimal.js
index 9e8b3039208f0..4ddf6b3b0303c 100644
--- a/src/shell_minimal.js
+++ b/src/shell_minimal.js
@@ -41,9 +41,6 @@ var readyPromise = new Promise((resolve, reject) => {
   readyPromiseResolve = resolve;
   readyPromiseReject = reject;
 });
-#if ASSERTIONS
-{{{ addReadyPromiseAssertions() }}}
-#endif
 #endif
 
 #if ENVIRONMENT_MAY_BE_NODE
diff --git a/test/test_other.py b/test/test_other.py
index ac84ed83aaa08..2648e1f1601f4 100644
--- a/test/test_other.py
+++ b/test/test_other.py
@@ -11962,31 +11962,6 @@ def test_assertions_on_outgoing_module_api_changes(self):
 '''
     self.do_runf('src.cpp', expected, emcc_args=['-sASSERTIONS'])
 
-  def test_modularize_assertions_on_ready_promise(self):
-    # check that when assertions are on we give useful error messages for
-    # mistakenly thinking the Promise is an instance. I.e., once you could do
-    # Module()._main to get an instance and the main function, but after
-    # the breaking change in #10697 Module() now returns a promise, and to get
-    # the instance you must use .then() to get a callback with the instance.
-    create_file('test.js', r'''
-      try {
-        Module()._main;
-      } catch(e) {
-        console.log(e);
-      }
-      try {
-        Module().onRuntimeInitialized = 42;
-      } catch(e) {
-        console.log(e);
-      }
-    ''')
-    self.run_process([EMCC, test_file('hello_world.c'), '-sMODULARIZE', '-sASSERTIONS', '--extern-post-js', 'test.js'])
-    # A return code of 1 is from an uncaught exception not handled by
-    # the domain or the 'uncaughtException' event handler.
-    out = self.run_js('a.out.js', assert_returncode=1)
-    self.assertContained('You are getting _main on the Promise object, instead of the instance. Use .then() to get called back with the instance, see the MODULARIZE docs in src/settings.js', out)
-    self.assertContained('You are setting onRuntimeInitialized on the Promise object, instead of the instance. Use .then() to get called back with the instance, see the MODULARIZE docs in src/settings.js', out)
-
   def test_modularize_assertions_on_reject_promise(self):
     # Check that there is an uncaught exception in modularize mode.
     # Once we added an `uncaughtException` handler to the global process