fix the version check on CPython: on a failed version check, the brok…

…en module was left inside sys.modules, with the consequence that a second import seemed to succeed O_o

capnpy/compiler/request.py

@@ -119,7 +119,7 @@ def emit(self, m):
         #
         m.w('__capnpy_version__ = {version!r}', version=capnpy.__version__)
         if m.version_check:
-            m.w('_check_version(__capnpy_version__)')
+            m.w('_check_version(__name__, __capnpy_version__)')
         else:
             m.w('# schema compiled with --no-version-check, skipping the call to _check_version')
         self._declare_imports(m)

capnpy/testing/compiler/test_standalone.py

@@ -150,8 +150,12 @@ def test_version_check(self, monkeypatch):
         }
         """)
         monkeypatch.setattr(capnpy, '__version__', 'Fake 2.0')
-        exc = py.test.raises(ImportError, "self.import_('example')")
-        expected = ('Version mismatch: the module has been compiled with capnpy '
-                    'Fake 1.0, but the current version of capnpy is Fake 2.0. '
-                    'Please recompile.')
-        assert str(exc.value) == expected
+        # try to import it twice: we need to take extra case to make sure that
+        # when in PYX mode, the module is not left inside sys.modules in case
+        # of version mismatch
+        for i in range(2):
+            exc = py.test.raises(ImportError, "self.import_('example')")
+            expected = ('Version mismatch: the module has been compiled with '
+                        'capnpy Fake 1.0, but the current version of capnpy '
+                        'is Fake 2.0. Please recompile.')
+            assert str(exc.value) == expected

capnpy/util.py

@@ -73,8 +73,13 @@ def extend_module_maybe(globals, filename=None, modname=None):
     code = compile(src, str(extmod), 'exec')
     exec(code, globals)
 
-def check_version(version):
+def check_version(modname, version):
     if version != capnpy.__version__:
+        # explicitly remove modname from sys.modules: apparently, CPython does
+        # not do it automatically if the module is an extension (which happens
+        # in PYX mode). See also
+        # testing/compiler/test_standalone:test_version_check
+        sys.modules.pop(modname, None)
         msg = ('Version mismatch: the module has been compiled with capnpy '
                '{v1}, but the current version of capnpy is {v2}. '
                'Please recompile.').format(v1=version, v2=capnpy.__version__)