modules/python: detect debian distutils missing and show an error

Signed-off-by: Filipe Laíns <[email protected]>

mesonbuild/modules/python.py

@@ -282,6 +282,21 @@ def set_env(name, value):
 import sys
 import distutils.command.install
 
+def debian_distutils_missing():
+    # Debian partially splits the distutils module from the python3, they
+    # keep distutils and distutils.version in python3 and put the rest of
+    # the submodules in python3-distutils
+    try:
+        import distutils
+        import distutils.version
+        try:
+            import distutils.core
+        except ImportError:
+            return True
+    except ImportError:
+        return False
+    return False
+
 def get_distutils_paths(scheme=None, prefix=None):
     import distutils.dist
     distribution = distutils.dist.Distribution()
@@ -320,16 +335,23 @@ def links_against_libpython():
     cmd.ensure_finalized()
     return bool(cmd.get_libraries(Extension('dummy', [])))
 
-print(json.dumps({
-  'variables': sysconfig.get_config_vars(),
-  'paths': paths,
-  'install_paths': install_paths,
-  'sys_paths': sys.path,
-  'version': sysconfig.get_python_version(),
-  'platform': sysconfig.get_platform(),
-  'is_pypy': '__pypy__' in sys.builtin_module_names,
-  'link_libpython': links_against_libpython(),
-}))
+if debian_distutils_missing():
+    data = {
+        'error': 'Debian distutils is missing, please install python3-distutils',
+    }
+else:
+    data = {
+        'variables': sysconfig.get_config_vars(),
+        'paths': paths,
+        'install_paths': install_paths,
+        'sys_paths': sys.path,
+        'version': sysconfig.get_python_version(),
+        'platform': sysconfig.get_platform(),
+        'is_pypy': '__pypy__' in sys.builtin_module_names,
+        'link_libpython': links_against_libpython(),
+    }
+
+print(json.dumps(data))
 '''
 
 if T.TYPE_CHECKING:
@@ -390,13 +412,18 @@ def sanity(self) -> bool:
             mlog.debug('Program stderr:\n')
             mlog.debug(stderr)
 
-        if info is not None and self._check_version(info['version']):
-            variables = info['variables']
-            info['suffix'] = variables.get('EXT_SUFFIX') or variables.get('SO') or variables.get('.so')
-            self.info = T.cast('PythonIntrospectionDict', info)
-            self.platlib = self._get_path('platlib')
-            self.purelib = self._get_path('purelib')
-            return True
+        if info is not None:
+            if 'error' in info:
+                assert isinstance(info['error'], str)
+                mlog.error('Python interpreter introspection failed: %s' % info['error'])
+                return False
+            elif self._check_version(info['version']):
+                variables = info['variables']
+                info['suffix'] = variables.get('EXT_SUFFIX') or variables.get('SO') or variables.get('.so')
+                self.info = T.cast('PythonIntrospectionDict', info)
+                self.platlib = self._get_path('platlib')
+                self.purelib = self._get_path('purelib')
+                return True
         else:
             return False
 

unittests/pythontests.py

@@ -14,11 +14,13 @@
 
 import os
 import unittest
+import unittest.mock
 
 from run_tests import (
     Backend
 )
 
+from mesonbuild.modules.python import PythonExternalProgram
 from .baseplatformtests import BasePlatformTests
 
 class PythonTests(BasePlatformTests):
@@ -80,3 +82,11 @@ def test_versions(self):
         with self.assertRaises(unittest.SkipTest):
             self.init(testdir, extra_args=['-Dpython=dir'])
         self.wipe()
+
+    @unittest.mock.patch('mesonbuild.mesonlib.Popen_safe', return_value=(None, '{"error": "hello!"}', None))
+    @unittest.mock.patch('mesonbuild.mlog.error')
+    def test_introspection_error(self, mlog_error, Popen_safe):
+        python = PythonExternalProgram('some-python', ['some-python'])
+
+        assert python.sanity() is False
+        mlog_error.assert_called_with('Python interpreter introspection failed: hello!')