Prohibit default pickling of classes with non-Python-convertable members.

Cython/Compiler/ParseTreeTransforms.py

@@ -1568,39 +1568,58 @@ if VALUE is not None:
         return node
 
     def _inject_pickle_methods(self, node):
+        env = self.current_env()
         all_members = []
         cls = node.entry.type
         while cls is not None:
             all_members.extend(cls.scope.var_entries)
             cls = cls.base_type
-        all_members.sort(key=lambda e: e.name)
-        all_members_names = [e.name for e in all_members]
-        unpickle_func_name = '__pyx_unpickle_%s' % node.class_name
-
-        unpickle_func = TreeFragment(u"""
-            def %(unpickle_func_name)s(%(args)s):
-                cdef %(class_name)s result
-                result = %(class_name)s.__new__(%(class_name)s)
-                %(assignments)s
-                return result
-            """ % {
-                'unpickle_func_name': unpickle_func_name,
-                'class_name': node.class_name,
-                'assignments': '; '.join('result.%s = %s' % (v, v) for v in all_members_names),
-                'args': ','.join(all_members_names),
-            }, level='module', pipeline=[NormalizeTree(None)]).substitute({})
-        unpickle_func.analyse_declarations(node.entry.scope)
-        self.visit(unpickle_func)
-        self.extra_module_declarations.append(unpickle_func)
-
-        pickle_func = TreeFragment(u"""
-            def __reduce__(self):
-                return %s, (%s)
-            """ % (unpickle_func_name, ', '.join('self.%s' % v for v in all_members_names)),
-            level='c_class', pipeline=[NormalizeTree(None)]).substitute({})
-        pickle_func.analyse_declarations(node.scope)
-        self.visit(pickle_func)
-        node.body.stats.append(pickle_func)
+            all_members.sort(key=lambda e: e.name)
+
+        non_py = [
+            e for e in all_members
+            if not e.type.is_pyobject and (not e.type.create_from_py_utility_code(env)
+                                           or not e.type.create_to_py_utility_code(env))]
+
+        if non_py:
+            msg = "%s cannot be converted to a Python object" % ','.join("self.%s" % e.name for e in non_py)
+            pickle_func = TreeFragment(u"""
+                def __reduce__(self):
+                    raise TypeError("%s")
+                """ % msg,
+                level='c_class', pipeline=[NormalizeTree(None)]).substitute({})
+            pickle_func.analyse_declarations(node.scope)
+            self.visit(pickle_func)
+            node.body.stats.append(pickle_func)
+
+        else:
+            all_members_names = [e.name for e in all_members]
+            unpickle_func_name = '__pyx_unpickle_%s' % node.class_name
+
+            unpickle_func = TreeFragment(u"""
+                def %(unpickle_func_name)s(%(args)s):
+                    cdef %(class_name)s result
+                    result = %(class_name)s.__new__(%(class_name)s)
+                    %(assignments)s
+                    return result
+                """ % {
+                    'unpickle_func_name': unpickle_func_name,
+                    'class_name': node.class_name,
+                    'assignments': '; '.join('result.%s = %s' % (v, v) for v in all_members_names),
+                    'args': ','.join(all_members_names),
+                }, level='module', pipeline=[NormalizeTree(None)]).substitute({})
+            unpickle_func.analyse_declarations(node.entry.scope)
+            self.visit(unpickle_func)
+            self.extra_module_declarations.append(unpickle_func)
+
+            pickle_func = TreeFragment(u"""
+                def __reduce__(self):
+                    return %s, (%s)
+                """ % (unpickle_func_name, ', '.join('self.%s' % v for v in all_members_names)),
+                level='c_class', pipeline=[NormalizeTree(None)]).substitute({})
+            pickle_func.analyse_declarations(node.scope)
+            self.visit(pickle_func)
+            node.body.stats.append(pickle_func)
 
     def _handle_fused_def_decorators(self, old_decorators, env, node):
         """

tests/run/reduce_pickle.pyx

@@ -96,3 +96,14 @@ cdef class DefaultReduceSubclass(DefaultReduce):
 
     def __repr__(self):
         return "DefaultReduceSubclass(i=%s, s=%r, x=%s)" % (self.i, self.s, self.x)
+
+
+cdef class NoReduceDueToIntPtr(object):
+    """
+    >>> import pickle
+    >>> pickle.dumps(NoReduceDueToIntPtr())
+    Traceback (most recent call last):
+    ...
+    TypeError: self.int_ptr cannot be converted to a Python object
+    """
+    cdef int* int_ptr