Make RPCError subclasses unpicklable again (#1387)

telethon_generator/generators/errors.py

@@ -26,13 +26,16 @@ def generate_errors(errors, f):
 
     # Error classes generation
     for error in errors:
-        f.write('\n\nclass {}({}):\n'
+        f.write('\n\nclass {}({}):\n    '.format(error.name, error.subclass))
-                '    def __init__(self, **kwargs):\n'
-                '        '.format(error.name, error.subclass))
 
         if error.has_captures:
-            f.write("self.{} = int(kwargs.get('capture', 0))\n        "
+            f.write('def __init__(self, request, capture=0):\n    '
+                    '    self.request = request\n    ')
+            f.write('    self.{} = int(capture)\n        '
                     .format(error.capture_name))
+        else:
+            f.write('def __init__(self, request):\n    '
+                    '    self.request = request\n        ')
 
         f.write('super(Exception, self).__init__('
                 '{}'.format(repr(error.description)))
@@ -40,7 +43,12 @@ def generate_errors(errors, f):
         if error.has_captures:
             f.write('.format({0}=self.{0})'.format(error.capture_name))
 
-        f.write(" + self._fmt_request(kwargs['request']))\n")
+        f.write(' + self._fmt_request(self.request))\n\n')
+        f.write('    def __reduce__(self):\n        ')
+        if error.has_captures:
+            f.write('return type(self), (self.request, self.{})\n'.format(error.capture_name))
+        else:
+            f.write('return type(self), (self.request,)\n')
 
     # Create the actual {CODE: ErrorClassName} dict once classes are defined
     f.write('\n\nrpc_errors_dict = {\n')

tests/telethon/test_pickle.py

@@ -0,0 +1,35 @@
+import pickle
+
+from telethon.errors import RPCError, BadRequestError, FileIdInvalidError, NetworkMigrateError
+
+
+def _assert_equality(error, unpickled_error):
+    assert error.code == unpickled_error.code
+    assert error.message == unpickled_error.message
+    assert type(error) == type(unpickled_error)
+    assert str(error) == str(unpickled_error)
+
+
+def test_base_rpcerror_pickle():
+    error = RPCError("request", "message", 123)
+    unpickled_error = pickle.loads(pickle.dumps(error))
+    _assert_equality(error, unpickled_error)
+
+
+def test_rpcerror_pickle():
+    error = BadRequestError("request", "BAD_REQUEST", 400)
+    unpickled_error = pickle.loads(pickle.dumps(error))
+    _assert_equality(error, unpickled_error)
+
+
+def test_fancy_rpcerror_pickle():
+    error = FileIdInvalidError("request")
+    unpickled_error = pickle.loads(pickle.dumps(error))
+    _assert_equality(error, unpickled_error)
+
+
+def test_fancy_rpcerror_capture_pickle():
+    error = NetworkMigrateError(request="request", capture=5)
+    unpickled_error = pickle.loads(pickle.dumps(error))
+    _assert_equality(error, unpickled_error)
+    assert error.new_dc == unpickled_error.new_dc