[3.14] pythongh-136251: Improvements to WASM demo REPL (pythonGH-136252) (pythonGH-136977)

(cherry picked from commit d1d526a)

Co-authored-by: adam j hartz <[email protected]>
Co-authored-by: Hood Chatham <[email protected]>

Author: 3 people

Makefile.pre.in

@@ -1096,7 +1096,7 @@ $(DLLLIBRARY) libpython$(LDVERSION).dll.a: $(LIBRARY_OBJS)
 # wasm32-emscripten browser web example
 
 WEBEX_DIR=$(srcdir)/Tools/wasm/emscripten/web_example/
-web_example/python.html: $(WEBEX_DIR)/python.html
+web_example/index.html: $(WEBEX_DIR)/index.html
 	@mkdir -p web_example
 	@cp $< $@
 
@@ -1124,7 +1124,7 @@ web_example/python.mjs web_example/python.wasm: $(BUILDPYTHON)
 	cp python.wasm web_example/python.wasm
 
 .PHONY: web_example
-web_example: web_example/python.mjs web_example/python.worker.mjs web_example/python.html web_example/server.py $(WEB_STDLIB)
+web_example: web_example/python.mjs web_example/python.worker.mjs web_example/index.html web_example/server.py $(WEB_STDLIB)
 
 ############################################################################
 # Header files

Misc/NEWS.d/next/Tools-Demos/2025-07-05-15-10-42.gh-issue-136251.GRM6o8.rst

@@ -0,0 +1 @@
+Fixes and usability improvements for ``Tools/wasm/emscripten/web_example``

Python/emscripten_syscalls.c

@@ -100,7 +100,7 @@ EM_JS_MACROS(void, _emscripten_promising_main_js, (void), {
         return;
     }
     const origResolveGlobalSymbol = resolveGlobalSymbol;
-    if (!Module.onExit && process?.exit) {
+    if (!Module.onExit && globalThis?.process?.exit) {
         Module.onExit = (code) => process.exit(code);
     }
     // * wrap the main symbol with WebAssembly.promising,

Tools/wasm/README.md

@@ -22,7 +22,7 @@ https://github.com/psf/webassembly for more information.
 ### Build
 
 To cross compile to the ``wasm32-emscripten`` platform you need
-[the Emscripten compiler toolchain](https://emscripten.org/), 
+[the Emscripten compiler toolchain](https://emscripten.org/),
 a Python interpreter, and an installation of Node version 18 or newer.
 Emscripten version 4.0.2 is recommended; newer versions may also work, but all
 official testing is performed with that version. All commands below are relative
@@ -86,11 +86,11 @@ CLI you will need to write your own alternative to `node_entry.mjs`.
 
 ### The Web Example
 
-When building for Emscripten, the web example will be built automatically. It is
-in the ``web_example`` directory. To run the web example, ``cd`` into the
+When building for Emscripten, the web example will be built automatically. It
+is in the ``web_example`` directory. To run the web example, ``cd`` into the
 ``web_example`` directory, then run ``python server.py``. This will start a web
-server; you can then visit ``http://localhost:8000/python.html`` in a browser to
-see a simple REPL example.
+server; you can then visit ``http://localhost:8000/`` in a browser to see a
+simple REPL example.
 
 The web example relies on a bug fix in Emscripten version 3.1.73 so if you build
 with earlier versions of Emscripten it may not work. The web example uses