gh-157649: Merge test_cppext into test_cext (#158176)

* test_cext now uses a single virtual environment for all tests.
  It makes the test way faster since creating a virtual environment
  is quite slow.
* Add Py_TARGET_ABI3T test on C++.
* Move macro tests from module exec function to test_macros().
* Call Py_BEGIN_CRITICAL_SECTION() on a fresh dictionary object,
  rather than on the module.
* Rename some environment variables to always use "CPYTHON_TEST_"
  prefix.
* Replace support.MS_WINDOWS with MSVC to be more explicit.
* Move macro tests to test_macros().
* On macOS, use C++11 by default.

Author: vstinner

Lib/test/pythoninfo.py

@@ -917,18 +917,17 @@ def collect_support_threading_helper(info_add):
     copy_attributes(info_add, threading_helper, 'support_threading_helper.%s', attributes)
 
 
-def collect_cc(info_add):
+def get_compiler_version(sysconfig_var):
     import sysconfig
-
-    CC = sysconfig.get_config_var('CC')
-    if not CC:
+    program = sysconfig.get_config_var(sysconfig_var)
+    if not program:
         return
 
     try:
         import shlex
-        args = shlex.split(CC)
+        args = shlex.split(program)
     except ImportError:
-        args = CC.split()
+        args = program.split()
     args.append('--version')
 
     stdout = run_command(args)
@@ -942,7 +941,21 @@ def collect_cc(info_add):
 
     text = first_line(stdout)
     text = normalize_text(text)
-    info_add('CC.version', text)
+    if text:
+        text = f'[{program}] {text}'
+    return text
+
+
+def collect_cc(info_add):
+    # C compiler
+    version = get_compiler_version('CC')
+    if version:
+        info_add('CC.version', version)
+
+    # C++ compiler
+    version = get_compiler_version('CXX')
+    if version:
+        info_add('CXX.version', version)
 
 
 def collect_gdbm(info_add):

Lib/test/test_cext/__init__.py

@@ -1,28 +1,37 @@
-# gh-116869: Build a basic C test extension to check that the Python C API
-# does not emit C compiler warnings.
+# gh-116869: Build a C/C++ test extension to check that the Python C API does
+# not emit compiler warnings.
 #
 # The Python C API must be compatible with building
 # with the -Werror=declaration-after-statement compiler flag.
 
 import os.path
+import platform
 import shlex
 import shutil
 import subprocess
-import sysconfig
 import sys
+import sysconfig
 import unittest
 from test import support
+from test.support import os_helper
+
+
+if not support.has_subprocess_support:
+    raise unittest.SkipTest("requires subprocess support")
 
 
+SOURCE_DIR = os.path.dirname(__file__)
 SOURCES = [
-    os.path.join(os.path.dirname(__file__), 'extension.c'),
+    os.path.join(SOURCE_DIR, 'extension.c'),
+    os.path.join(SOURCE_DIR, 'extension.cpp'),
+    os.path.join(SOURCE_DIR, 'setup.py'),
 ]
-SETUP = os.path.join(os.path.dirname(__file__), 'setup.py')
+MSVC = support.MS_WINDOWS
 
 
 # With MSVC on a debug build, the linker fails with: cannot open file
 # 'python311.lib', it should look 'python311_d.lib'.
-@unittest.skipIf(support.MS_WINDOWS and support.Py_DEBUG,
+@unittest.skipIf(MSVC and support.Py_DEBUG,
                  'test fails on Windows debug build')
 # Building and running an extension in clang sanitizing mode is not
 # straightforward
@@ -34,41 +43,38 @@
 @support.requires_resource('cpu')
 class BaseTests:
     TEST_INTERNAL_C_API = False
-
-    # Default build with no options
-    def test_build(self):
-        self.check_build('_test_cext')
+    LANGUAGE = None
 
     def check_build(self, extension_name, std=None, limited=False,
-                    abi3t=False):
-        venv_dir = 'env'
-        with support.setup_venv_with_pip_setuptools(venv_dir) as python_exe:
-            self._check_build(extension_name, python_exe,
-                              std=std, limited=limited,
-                              abi3t=abi3t)
-
-    def _check_build(self, extension_name, python_exe, std, limited,
-                     abi3t):
+                    abi3t=False, extra_cflags=None):
+        if self.LANGUAGE == 'C++' and not std and sys.platform == 'darwin':
+            # Old Apple clang++ default C++ std is gnu++98, use C++11 instead
+            std = 'c++11'
+
         pkg_dir = 'pkg'
         os.mkdir(pkg_dir)
-        shutil.copy(SETUP, os.path.join(pkg_dir, os.path.basename(SETUP)))
+        self.addCleanup(os_helper.rmtree, pkg_dir)
+
         for source in SOURCES:
             dest = os.path.join(pkg_dir, os.path.basename(source))
             shutil.copy(source, dest)
 
         def run_cmd(operation, cmd):
             env = os.environ.copy()
+            env['CPYTHON_TEST_EXT_NAME'] = extension_name
+            env['CPYTHON_TEST_LANG'] = self.LANGUAGE
             if std:
                 env['CPYTHON_TEST_STD'] = std
             if limited:
                 env['CPYTHON_TEST_LIMITED'] = '1'
             if abi3t:
                 env['CPYTHON_TEST_ABI3T'] = '1'
-            if support.MS_WINDOWS and sysconfig.is_python_build():
-                env['CPYTHON_EXTRA_INCDIRS'] = os.path.split(sysconfig.get_config_h_filename())[0]
-                env['CPYTHON_EXTRA_LIBDIRS'] = os.path.split(sys.executable)[0]
-            env['CPYTHON_TEST_EXT_NAME'] = extension_name
-            env['TEST_INTERNAL_C_API'] = str(int(self.TEST_INTERNAL_C_API))
+            if MSVC and sysconfig.is_python_build():
+                env['CPYTHON_TEST_EXTRA_INCDIRS'] = os.path.split(sysconfig.get_config_h_filename())[0]
+                env['CPYTHON_TEST_EXTRA_LIBDIRS'] = os.path.split(sys.executable)[0]
+            env['CPYTHON_TEST_INTERNAL_C_API'] = str(int(self.TEST_INTERNAL_C_API))
+            if extra_cflags:
+                env['CPYTHON_TEST_EXTRA_CFLAGS'] = extra_cflags
             if support.verbose:
                 print('Run:', ' '.join(map(shlex.quote, cmd)))
                 subprocess.run(cmd, check=True, env=env)
@@ -85,6 +91,7 @@ def run_cmd(operation, cmd):
                         f"{operation} failed with exit code {proc.returncode}")
 
         # Build and install the C extension
+        python_exe = PYTHON_EXE
         cmd = [python_exe, '-X', 'dev',
                '-m', 'pip', 'install', '--no-build-isolation',
                os.path.abspath(pkg_dir)]
@@ -101,39 +108,109 @@ def run_cmd(operation, cmd):
                '-c', 'pass']
         run_cmd('Reference run', cmd)
 
-        # Import the C extension
+        # Import the C/C++ extension
         cmd = [python_exe,
                '-X', 'dev',
                '-X', 'showrefcount',
                '-c', f"import {extension_name}"]
         run_cmd('Import', cmd)
 
 
-class TestPublicCAPI(BaseTests, unittest.TestCase):
+class TestPublicC(BaseTests, unittest.TestCase):
+    LANGUAGE = 'C'
+
+    # Default build with no options
+    def test_build(self):
+        self.check_build('_test_cext')
+
+    @unittest.skipIf(MSVC, "MSVC doesn't support /std:c99")
+    def test_build_c99(self):
+        # In public docs, we say C API is compatible with C11. However,
+        # in practice we do maintain C99 compatibility in public headers.
+        # Please ask the C API WG before adding a new C11-only feature.
+        self.check_build('_test_cext_c99', std='c99')
+
+    def test_build_c11(self):
+        self.check_build('_test_cext_c11', std='c11')
+
     def test_build_limited(self):
-        self.check_build('_test_limited_cext', limited=True)
+        self.check_build('_test_cext_limited', limited=True)
 
     def test_build_limited_c11(self):
-        self.check_build('_test_limited_c11_cext', limited=True, std='c11')
+        self.check_build('_test_cext_limited_c11', limited=True, std='c11')
 
-    def test_build_c11(self):
-        self.check_build('_test_c11_cext', std='c11')
+    def test_build_abi3t(self):
+        # Test with Py_TARGET_ABI3T
+        self.check_build('_test_cext_abi3t', abi3t=True)
+
+
+class TestPublicCpp(BaseTests, unittest.TestCase):
+    LANGUAGE = 'C++'
+
+    def test_build(self):
+        self.check_build('_test_cppext')
+
+    def test_build_cpp03(self):
+        # In public docs, we say C API is compatible with C++11. However,
+        # in practice we do maintain C++03 compatibility in public headers.
+        # Please ask the C API WG before adding a new C++11-only feature.
+        self.check_build('_test_cppext_cpp03', std='c++03')
+
+    @unittest.skipIf(MSVC, "MSVC doesn't support /std:c++11")
+    def test_build_cpp11(self):
+        self.check_build('_test_cppext_cpp11', std='c++11')
+
+    # Only test C++14 on MSVC.
+    # On s390x RHEL7, GCC 4.8.5 doesn't support C++14.
+    @unittest.skipIf(not MSVC, "need MSVC")
+    def test_build_cpp14(self):
+        self.check_build('_test_cppext_cpp14', std='c++14')
+
+    # Test that headers compile with Intel asm syntax, which may conflict
+    # with inline assembly in free-threading headers that use AT&T syntax.
+    @unittest.skipIf(MSVC, "MSVC doesn't support -masm=intel")
+    @unittest.skipUnless(platform.machine() in ('x86_64', 'i686', 'AMD64'),
+                         "x86-specific flag")
+    def test_build_intel_asm(self):
+        self.check_build('_test_cppext_intel_asm', extra_cflags='-masm=intel')
+
+    def test_build_limited(self):
+        self.check_build('_test_cppext_limited', limited=True)
+
+    def test_build_limited_cpp03(self):
+        self.check_build('_test_cppext_limited_cpp03', std='c++03', limited=True)
 
     def test_build_abi3t(self):
         # Test with Py_TARGET_ABI3T
-        self.check_build('_test_abi3t', abi3t=True)
+        self.check_build('_test_cppext_abi3t', abi3t=True)
 
-    @unittest.skipIf(support.MS_WINDOWS, "MSVC doesn't support /std:c99")
-    def test_build_c99(self):
-        # In public docs, we say C API is compatible with C11. However,
-        # in practice we do maintain C99 compatibility in public headers.
-        # Please ask the C API WG before adding a new C11-only feature.
-        self.check_build('_test_c99_cext', std='c99')
+
+class TestInteralC(BaseTests, unittest.TestCase):
+    LANGUAGE = 'C'
+    TEST_INTERNAL_C_API = True
+
+    # Default build with no options
+    def test_build(self):
+        self.check_build('_test_cext_internal')
 
 
-class TestInteralCAPI(BaseTests, unittest.TestCase):
+class TestInteralCpp(BaseTests, unittest.TestCase):
+    LANGUAGE = 'C++'
     TEST_INTERNAL_C_API = True
 
+    def test_build(self):
+        self.check_build('_test_cppext_internal')
+
+
+def setUpModule():
+    global VENV_CONTEXT, PYTHON_EXE
+    VENV_CONTEXT = support.setup_venv_with_pip_setuptools('env')
+    PYTHON_EXE = VENV_CONTEXT.__enter__()
+
+
+def tearDownModule():
+    VENV_CONTEXT.__exit__(None, None, None)
+
 
 if __name__ == "__main__":
     unittest.main()