plugin_error: output to stderr

Author: blueyed

mypy/build.py

@@ -352,7 +352,7 @@ def load_plugins(options: Options,
 
     def plugin_error(message: str) -> None:
         errors.report(line, 0, message)
-        errors.raise_error()
+        errors.raise_error(use_stdout=False)
 
     custom_plugins = []  # type: List[Plugin]
     errors.set_file(options.config_file, None)

mypy/errors.py

@@ -399,15 +399,15 @@ def is_errors_for_file(self, file: str) -> bool:
         """Are there any errors for the given file?"""
         return file in self.error_info_map
 
-    def raise_error(self) -> None:
+    def raise_error(self, use_stdout: bool = True) -> None:
         """Raise a CompileError with the generated messages.
 
         Render the messages suitable for displaying.
         """
         # self.new_messages() will format all messages that haven't already
         # been returned from a file_messages() call.
         raise CompileError(self.new_messages(),
-                           use_stdout=True,
+                           use_stdout=use_stdout,
                            module_with_blocker=self.blocker_module())
 
     def format_messages(self, error_info: List[ErrorInfo],