Hello,

I think I found a bug in debbugs, however I am not sure if the bug is in
documentation or in the code.  Steps to reproduce (in emacs -Q):

In *scratch* buffer:
   (require 'debbugs-gnu)
   (debbugs-gnu-bugs 66531)

In the new buffer open the message and navigate cursor to last message from Mike
Gran (47: ).  Now, when I want to reply, I press S v and it opens a buffer with
(addresses are censored):

    To: Mike Gran <xxx>
    Cc: Tomas Volf <xxx>,  "xxx@debbugs-gnu-org" <xxx>
    Subject: Re: bug#66531: [PATCH] ftw: Fix getuid-or-false, getgid-or-false macros.
    From: me@hostname.mail-host-address-is-not-set
    --text follows this line--

So far that is expected.  However when I want to quote the original message, I can, based on the reading of the manual, use C-u S v:

> If prefix argument YANK is non-nil, the original article(s) will be yanked
> automatically.

However while that does work, additional undocumented (and unwanted) changes are
done as well,producing a following message:

    To: Mike Gran <xxx>
    Cc: Tomas Volf <xxx>,  Tomas Volf <xxx>,  control@debbugs-gnu-org,  xxx@debbugs-gnu-org
    Subject: Re: bug#66531: [PATCH] ftw: Fix getuid-or-false, getgid-or-false macros., bug#66531: [PATCH] ftw: Fix getuid-or-false, getgid-or-false macros., bug#66531: [PATCH] ftw: Fix getuid-or-false, getgid-or-false macros., bug#66531: [PATCH] ftw: Fix getuid-or-false, getgid-or-false macros., control message for bug #66531, control message for bug #66531
    From: me@hostname.mail-host-address-is-not-set
    --text follows this line--
    Mike Gran <xxx> writes:
    
    [..]

Notice that the subject is pretty weird, and for some reason there is a control
server in the CC list.  I do not know if this is expected (well, at least I did
not expect it), but it at the very least does not seem to be documented.  Based
on my reading of the C-h k S v I would have expected just the "Mike Gran
<xxx> writes:" change.

Thank you and have a nice day,
Tomas Volf

-- 
There are only two hard things in Computer Science:
cache invalidation, naming things and off-by-one errors.