gh-116869: Test the limited C API in test_cext (#116995)

Lib/test/test_cext/__init__.py

@@ -27,17 +27,24 @@ SETUP = os.path.join(os.path.dirname(__file__), 'setup.py')
 @support.requires_resource('cpu')
 class TestExt(unittest.TestCase):
     def test_build_c99(self):
-        self.check_build('c99', '_test_c99_ext')
+        self.check_build('_test_c99_ext', std='c99')
 
     def test_build_c11(self):
-        self.check_build('c11', '_test_c11_ext')
+        self.check_build('_test_c11_ext', std='c11')
 
-    def check_build(self, clang_std, extension_name):
+    def test_build_limited(self):
+        self.check_build('_test_limited_ext', limited=True)
+
+    def test_build_limited_c11(self):
+        self.check_build('_test_limited_c11_ext', limited=True, std='c11')
+
+    def check_build(self, extension_name, std=None, limited=False):
         venv_dir = 'env'
         with support.setup_venv_with_pip_setuptools_wheel(venv_dir) as python_exe:
-            self._check_build(clang_std, extension_name, python_exe)
+            self._check_build(extension_name, python_exe,
+                              std=std, limited=limited)
 
-    def _check_build(self, clang_std, extension_name, python_exe):
+    def _check_build(self, extension_name, python_exe, std, limited):
         pkg_dir = 'pkg'
         os.mkdir(pkg_dir)
         shutil.copy(SETUP, os.path.join(pkg_dir, os.path.basename(SETUP)))
@@ -45,7 +52,10 @@ class TestExt(unittest.TestCase):
 
         def run_cmd(operation, cmd):
             env = os.environ.copy()
-            env['CPYTHON_TEST_STD'] = clang_std
+            if std:
+                env['CPYTHON_TEST_STD'] = std
+            if limited:
+                env['CPYTHON_TEST_LIMITED'] = '1'
             env['CPYTHON_TEST_EXT_NAME'] = extension_name
             if support.verbose:
                 print('Run:', ' '.join(cmd))

Lib/test/test_cext/extension.c

@@ -6,12 +6,8 @@
 
 #include "Python.h"
 
-#if defined (__STDC_VERSION__) && __STDC_VERSION__ > 201710L
-#  define NAME _test_c2x_ext
-#elif defined (__STDC_VERSION__) && __STDC_VERSION__ >= 201112L
-#  define NAME _test_c11_ext
-#else
-#  define NAME _test_c99_ext
+#ifndef MODULE_NAME
+#  error "MODULE_NAME macro must be defined"
 #endif
 
 #define _STR(NAME) #NAME
@@ -25,11 +21,11 @@ PyDoc_STRVAR(_testcext_add_doc,
 static PyObject *
 _testcext_add(PyObject *Py_UNUSED(module), PyObject *args)
 {
-    long i, j;
+    long i, j, res;
     if (!PyArg_ParseTuple(args, "ll:foo", &i, &j)) {
         return NULL;
     }
-    long res = i + j;
+    res = i + j;
     return PyLong_FromLong(res);
 }
 
@@ -59,7 +55,7 @@ PyDoc_STRVAR(_testcext_doc, "C test extension.");
 
 static struct PyModuleDef _testcext_module = {
     PyModuleDef_HEAD_INIT,  // m_base
-    STR(NAME),  // m_name
+    STR(MODULE_NAME),  // m_name
     _testcext_doc,  // m_doc
     0,  // m_size
     _testcext_methods,  // m_methods
@@ -74,7 +70,7 @@ static struct PyModuleDef _testcext_module = {
 #define FUNC_NAME(NAME) _FUNC_NAME(NAME)
 
 PyMODINIT_FUNC
-FUNC_NAME(NAME)(void)
+FUNC_NAME(MODULE_NAME)(void)
 {
     return PyModuleDef_Init(&_testcext_module);
 }

Lib/test/test_cext/setup.py

@@ -27,24 +27,43 @@ else:
 
 
 def main():
-    std = os.environ["CPYTHON_TEST_STD"]
-    name = os.environ["CPYTHON_TEST_EXT_NAME"]
-    cflags = [*CFLAGS, f'-std={std}']
+    std = os.environ.get("CPYTHON_TEST_STD", "")
+    module_name = os.environ["CPYTHON_TEST_EXT_NAME"]
+    limited = bool(os.environ.get("CPYTHON_TEST_LIMITED", ""))
 
-    # Remove existing -std options to only test ours
-    cmd = (sysconfig.get_config_var('CC') or '')
-    if cmd is not None:
-        cmd = shlex.split(cmd)
-        cmd = [arg for arg in cmd if not arg.startswith('-std=')]
-        cmd = shlex.join(cmd)
-        # CC env var overrides sysconfig CC variable in setuptools
-        os.environ['CC'] = cmd
+    cflags = list(CFLAGS)
+    cflags.append(f'-DMODULE_NAME={module_name}')
+
+    if std:
+        cflags.append(f'-std={std}')
+
+        # Remove existing -std options to only test ours
+        cmd = (sysconfig.get_config_var('CC') or '')
+        if cmd is not None:
+            cmd = shlex.split(cmd)
+            cmd = [arg for arg in cmd if not arg.startswith('-std=')]
+            cmd = shlex.join(cmd)
+            # CC env var overrides sysconfig CC variable in setuptools
+            os.environ['CC'] = cmd
+
+    if limited:
+        version = sys.hexversion
+        cflags.append(f'-DPy_LIMITED_API={version:#x}')
+
+    for env_name in ('CC', 'CFLAGS'):
+        if env_name in os.environ:
+            print(f"{env_name} env var: {os.environ[env_name]!r}")
+        else:
+            print(f"{env_name} env var: <missing>")
+    print(f"extra_compile_args: {cflags!r}")
 
     ext = Extension(
-        name,
+        module_name,
         sources=[SOURCE],
         extra_compile_args=cflags)
-    setup(name='internal' + name, version='0.0', ext_modules=[ext])
+    setup(name=f'internal_{module_name}',
+          version='0.0',
+          ext_modules=[ext])
 
 
 if __name__ == "__main__":