From 9f19ec9eef86bd6301ce02fde3aa4c3b5a213cc6 Mon Sep 17 00:00:00 2001
From: Brendan Dahl <brendan.dahl@gmail.com>
Date: Tue, 16 Apr 2024 10:28:07 -0700
Subject: [PATCH] [tsgen] Fix modularize definition for sync compilation.
 (#21766)

Fixes #21760
---
 test/other/test_emit_tsd_sync.d.ts | 21 +++++++++++++++++++++
 test/other/test_tsd_sync.ts        |  5 +++++
 test/test_other.py                 | 11 +++++++++++
 tools/emscripten.py                |  5 ++++-
 4 files changed, 41 insertions(+), 1 deletion(-)
 create mode 100644 test/other/test_emit_tsd_sync.d.ts
 create mode 100644 test/other/test_tsd_sync.ts

diff --git a/test/other/test_emit_tsd_sync.d.ts b/test/other/test_emit_tsd_sync.d.ts
new file mode 100644
index 0000000000000..37d370ec26a46
--- /dev/null
+++ b/test/other/test_emit_tsd_sync.d.ts
@@ -0,0 +1,21 @@
+// TypeScript bindings for emscripten-generated code.  Automatically generated at compile time.
+declare namespace RuntimeExports {
+    let HEAPF64: any;
+    let HEAP_DATA_VIEW: any;
+    let HEAP8: any;
+    let HEAPU8: any;
+    let HEAP16: any;
+    let HEAPU16: any;
+    let HEAP32: any;
+    let HEAPU32: any;
+    let HEAP64: any;
+    let HEAPU64: any;
+}
+interface WasmModule {
+  _fooVoid(): void;
+  _fooInt(_0: number, _1: number): number;
+  _main(_0: number, _1: number): number;
+}
+
+export type MainModule = WasmModule & typeof RuntimeExports;
+export default function MainModuleFactory (options?: unknown): MainModule;
diff --git a/test/other/test_tsd_sync.ts b/test/other/test_tsd_sync.ts
new file mode 100644
index 0000000000000..49ef1381046d9
--- /dev/null
+++ b/test/other/test_tsd_sync.ts
@@ -0,0 +1,5 @@
+import moduleFactory from './test_emit_tsd_sync.js'
+
+const module = moduleFactory();
+module._fooVoid();
+module._fooInt(7, 8);
diff --git a/test/test_other.py b/test/test_other.py
index cd8da1fdbf628..941ede3b1016a 100644
--- a/test/test_other.py
+++ b/test/test_other.py
@@ -3307,6 +3307,17 @@ def test_emit_tsd(self):
     cmd = shared.get_npm_cmd('tsc') + [test_file('other/test_tsd.ts'), '--noEmit']
     shared.check_call(cmd)
 
+  def test_emit_tsd_sync_compilation(self):
+    self.run_process([EMCC, test_file('other/test_emit_tsd.c'),
+                      '--emit-tsd', 'test_emit_tsd_sync.d.ts',
+                      '-sMODULARIZE', '-sWASM_ASYNC_COMPILATION=0',
+                      '-o', 'test_emit_tsd_sync.js'] +
+                     self.get_emcc_args())
+    self.assertFileContents(test_file('other/test_emit_tsd_sync.d.ts'), read_file('test_emit_tsd_sync.d.ts'))
+    # Test that the output compiles with a TS file that uses the defintions.
+    cmd = shared.get_npm_cmd('tsc') + [test_file('other/test_tsd_sync.ts'), '--noEmit']
+    shared.check_call(cmd)
+
   def test_emit_tsd_wasm_only(self):
     err = self.expect_fail([EMCC, test_file('other/test_emit_tsd.c'),
                             '--emit-tsd', 'test_emit_tsd_wasm_only.d.ts', '-o', 'out.wasm'])
diff --git a/tools/emscripten.py b/tools/emscripten.py
index 3217c1d6d7eca..08356b8f0cd4b 100644
--- a/tools/emscripten.py
+++ b/tools/emscripten.py
@@ -664,7 +664,10 @@ def create_tsd(metadata, embind_tsd):
     export_interfaces += ' & EmbindModule'
   out += f'export type MainModule = {export_interfaces};\n'
   if settings.MODULARIZE:
-    out += 'export default function MainModuleFactory (options?: unknown): Promise<MainModule>;\n'
+    return_type = 'MainModule'
+    if settings.WASM_ASYNC_COMPILATION:
+      return_type = f'Promise<{return_type}>'
+    out += f'export default function MainModuleFactory (options?: unknown): {return_type};\n'
   return out