Fix inspect.getsource for classes created in PyREPL.

Lib/inspect.py

@@ -818,11 +818,12 @@ def getfile(object):
         raise TypeError('{!r} is a built-in module'.format(object))
     if isclass(object):
         if hasattr(object, '__module__'):
+            # Protect against fetching the wrong source in PyREPL
+            if object.__module__ == '__main__':
+                raise OSError('source code not available')
             module = sys.modules.get(object.__module__)
             if getattr(module, '__file__', None):
                 return module.__file__
-            if object.__module__ == '__main__':
-                raise OSError('source code not available')
         raise TypeError('{!r} is a built-in class'.format(object))
     if ismethod(object):
         object = object.__func__

Lib/test/test_pyrepl/test_pyrepl.py

@@ -1318,6 +1318,12 @@ def test_null_byte(self):
         self.assertEqual(exit_code, 0)
         self.assertNotIn("TypeError", output)
 
+    def test_inspect_getsource(self):
+        code = "import inspect\nclass A: pass\nprint(inspect.getsource(A))"
+        output, exit_code = self.run_repl(code)
+        self.assertNotEqual(exit_code, 0)
+        self.assertIn("OSError('source code not available')", output)
+
     def test_readline_history_file(self):
         # skip, if readline module is not available
         readline = import_module('readline')