1  # gh-91321: Build a basic C++ test extension to check that the Python C API is
       2  # compatible with C++ and does not emit C++ compiler warnings.
       3  import os.path
       4  import shutil
       5  import sys
       6  import unittest
       7  import subprocess
       8  import sysconfig
       9  from test import support
      10  from test.support import os_helper
      11  
      12  
      13  MS_WINDOWS = (sys.platform == 'win32')
      14  SOURCE = os.path.join(os.path.dirname(__file__), 'extension.cpp')
      15  SETUP = os.path.join(os.path.dirname(__file__), 'setup.py')
      16  
      17  
      18  @support.requires_subprocess()
      19  class ESC[4;38;5;81mTestCPPExt(ESC[4;38;5;149munittestESC[4;38;5;149m.ESC[4;38;5;149mTestCase):
      20      @support.requires_resource('cpu')
      21      def test_build_cpp11(self):
      22          self.check_build(False, '_testcpp11ext')
      23  
      24      @support.requires_resource('cpu')
      25      def test_build_cpp03(self):
      26          self.check_build(True, '_testcpp03ext')
      27  
      28      # With MSVC, the linker fails with: cannot open file 'python311.lib'
      29      # https://github.com/python/cpython/pull/32175#issuecomment-1111175897
      30      @unittest.skipIf(MS_WINDOWS, 'test fails on Windows')
      31      # Building and running an extension in clang sanitizing mode is not
      32      # straightforward
      33      @unittest.skipIf(
      34          '-fsanitize' in (sysconfig.get_config_var('PY_CFLAGS') or ''),
      35          'test does not work with analyzing builds')
      36      # the test uses venv+pip: skip if it's not available
      37      @support.requires_venv_with_pip()
      38      def check_build(self, std_cpp03, extension_name):
      39          venv_dir = 'env'
      40          with support.setup_venv_with_pip_setuptools_wheel(venv_dir) as python_exe:
      41              self._check_build(std_cpp03, extension_name, python_exe)
      42  
      43      def _check_build(self, std_cpp03, extension_name, python_exe):
      44          pkg_dir = 'pkg'
      45          os.mkdir(pkg_dir)
      46          shutil.copy(SETUP, os.path.join(pkg_dir, os.path.basename(SETUP)))
      47          shutil.copy(SOURCE, os.path.join(pkg_dir, os.path.basename(SOURCE)))
      48  
      49          def run_cmd(operation, cmd):
      50              env = os.environ.copy()
      51              env['CPYTHON_TEST_CPP_STD'] = 'c++03' if std_cpp03 else 'c++11'
      52              env['CPYTHON_TEST_EXT_NAME'] = extension_name
      53              if support.verbose:
      54                  print('Run:', ' '.join(cmd))
      55                  subprocess.run(cmd, check=True, env=env)
      56              else:
      57                  proc = subprocess.run(cmd,
      58                                        env=env,
      59                                        stdout=subprocess.PIPE,
      60                                        stderr=subprocess.STDOUT,
      61                                        text=True)
      62                  if proc.returncode:
      63                      print(proc.stdout, end='')
      64                      self.fail(
      65                          f"{operation} failed with exit code {proc.returncode}")
      66  
      67          # Build and install the C++ extension
      68          cmd = [python_exe, '-X', 'dev',
      69                 '-m', 'pip', 'install', '--no-build-isolation',
      70                 os.path.abspath(pkg_dir)]
      71          run_cmd('Install', cmd)
      72  
      73          # Do a reference run. Until we test that running python
      74          # doesn't leak references (gh-94755), run it so one can manually check
      75          # -X showrefcount results against this baseline.
      76          cmd = [python_exe,
      77                 '-X', 'dev',
      78                 '-X', 'showrefcount',
      79                 '-c', 'pass']
      80          run_cmd('Reference run', cmd)
      81  
      82          # Import the C++ extension
      83          cmd = [python_exe,
      84                 '-X', 'dev',
      85                 '-X', 'showrefcount',
      86                 '-c', f"import {extension_name}"]
      87          run_cmd('Import', cmd)
      88  
      89  
      90  if __name__ == "__main__":
      91      unittest.main()