message-send-news-hook : external filter and "raw utf-8" body

[Andrzej A. Filip]

I am trying to deploy the answer regarding filtering typical usenet messages
„rewrite outgoing messages/posts by external program/filter”
http://stackoverflow.com/a/31451576/2139766

It fails to process message with "raw utf-8" bodies when deployed using
message-send-news-hook. It gives error:

Assertion failed: (save-excursion (goto-char (point-min)) (not 
(re-search-forward "^\000-\377]" nil t)))

[The error message is displayed slightly differently than defined in 
gnus/message.el.]

It seems that gnus threats legitimate "raw utf-8" characters in message
body as lack of proper encoding.

How to make the recipe process corectly "raw utf-8" message bodies?



Mime headers of the filtered message:

Mime-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: 8bit