bpo-40280: Misc fixes for wasm32-emscripten (GH-30722)

Lib/test/test___all__.py

@@ -3,6 +3,12 @@
 from test.support import warnings_helper
 import os
 import sys
+import types
+
+try:
+    import _multiprocessing
+except ModuleNotFoundError:
+    _multiprocessing = None
 
 
 class NoAll(RuntimeError):
@@ -14,6 +20,17 @@ class FailedImport(RuntimeError):
 
 class AllTest(unittest.TestCase):
 
+    def setUp(self):
+        # concurrent.futures uses a __getattr__ hook. Its __all__ triggers
+        # import of a submodule, which fails when _multiprocessing is not
+        # available.
+        if _multiprocessing is None:
+            sys.modules["_multiprocessing"] = types.ModuleType("_multiprocessing")
+
+    def tearDown(self):
+        if _multiprocessing is None:
+            sys.modules.pop("_multiprocessing")
+
     def check_all(self, modname):
         names = {}
         with warnings_helper.check_warnings(

Lib/test/test_capi.py

@@ -26,6 +26,10 @@
     import _posixsubprocess
 except ImportError:
     _posixsubprocess = None
+try:
+    import _testmultiphase
+except ImportError:
+    _testmultiphase = None
 
 # Skip this test if the _testcapi module isn't available.
 _testcapi = import_helper.import_module('_testcapi')
@@ -798,6 +802,7 @@ def test_mutate_exception(self):
 
         self.assertFalse(hasattr(binascii.Error, "foobar"))
 
+    @unittest.skipIf(_testmultiphase is None, "test requires _testmultiphase module")
     def test_module_state_shared_in_global(self):
         """
         bpo-44050: Extension module state should be shared between interpreters
@@ -991,6 +996,7 @@ class PyMemDefaultTests(PyMemDebugTests):
     PYTHONMALLOC = ''
 
 
+@unittest.skipIf(_testmultiphase is None, "test requires _testmultiphase module")
 class Test_ModuleStateAccess(unittest.TestCase):
     """Test access to module start (PEP 573)"""
 

Lib/test/test_compileall.py

@@ -15,14 +15,14 @@
 import unittest
 
 from unittest import mock, skipUnless
-from concurrent.futures import ProcessPoolExecutor
 try:
     # compileall relies on ProcessPoolExecutor if ProcessPoolExecutor exists
     # and it can function.
+    from concurrent.futures import ProcessPoolExecutor
     from concurrent.futures.process import _check_system_limits
     _check_system_limits()
     _have_multiprocessing = True
-except NotImplementedError:
+except (NotImplementedError, ModuleNotFoundError):
     _have_multiprocessing = False
 
 from test import support

Lib/test/test_imp.py

@@ -23,7 +23,7 @@ def requires_load_dynamic(meth):
     """Decorator to skip a test if not running under CPython or lacking
     imp.load_dynamic()."""
     meth = support.cpython_only(meth)
-    return unittest.skipIf(not hasattr(imp, 'load_dynamic'),
+    return unittest.skipIf(getattr(imp, 'load_dynamic', None) is None,
                            'imp.load_dynamic() required')(meth)
 
 

Lib/test/test_pty.py

@@ -1,8 +1,9 @@
 from test.support import verbose, reap_children
 from test.support.import_helper import import_module
 
-# Skip these tests if termios is not available
+# Skip these tests if termios or fcntl are not available
 import_module('termios')
+import_module("fcntl")
 
 import errno
 import os

Lib/test/test_tracemalloc.py

@@ -346,7 +346,7 @@ def fork_child(self):
         # everything is fine
         return 0
 
-    @unittest.skipUnless(hasattr(os, 'fork'), 'need os.fork()')
+    @support.requires_fork()
     def test_fork(self):
         # check that tracemalloc is still working after fork
         pid = os.fork()

Tools/wasm/config.site-wasm32-emscripten

@@ -58,12 +58,14 @@ ac_cv_func_fchmodat=no
 ac_cv_func_dup3=no
 
 # Syscalls not implemented in emscripten
+# [Errno 52] Function not implemented
 ac_cv_func_preadv2=no
 ac_cv_func_preadv=no
 ac_cv_func_pwritev2=no
 ac_cv_func_pwritev=no
 ac_cv_func_pipe2=no
 ac_cv_func_nice=no
+ac_cv_func_setitimer=no
 
 # Syscalls that resulted in a segfault
 ac_cv_func_utimensat=no

configure

@@ -21323,7 +21323,7 @@ case $ac_sys_system/$ac_sys_emscripten_target in #(
    ;; #(
       Emscripten/node) :
 
-    py_stdlib_not_available="_ctypes _curses _curses_panel _dbm _gdbm _scproxy _tkinter nis ossaudiodev spwd syslog"
+    py_stdlib_not_available="_ctypes _curses _curses_panel _dbm _gdbm _scproxy _tkinter _xxsubinterpreters grp nis ossaudiodev spwd syslog"
    ;; #(
   *) :
     py_stdlib_not_available="_scproxy"

configure.ac

@@ -6384,6 +6384,8 @@ AS_CASE([$ac_sys_system/$ac_sys_emscripten_target],
       _gdbm
       _scproxy
       _tkinter
+      _xxsubinterpreters
+      grp
       nis
       ossaudiodev
       spwd