bug#29767: 26.0.90; Failing auto-fill in message-mode because of bad state (comment-skip-end)

[Katsumi Yamaoka]

On Tue, 19 Dec 2017 18:16:23 +0200, Eli Zaretskii wrote:
>> "Jose A. Ortega Ruiz" <jao@gnu.org> writes:

>>>   - sometimes, when composing a reply to an email in gnus (major mode is
>>>     message-mode there, auto-fill-mode is enabled), when a line is
>>>     auto-filled and broken in two, do-auto-fill incorrectly thinks that
>>>     it is inside a comment and adds a `> ' prefix to it.

>> This has bugged me for a long time.  I also don't have a recipe, the
>> issue has a Heisenbug-like behavior.  But it happens quite often - it
>>>     even happens right now, I didn't comment this line.

> What does "C-h l" show immediately after this happens?

I found a way to reproduce this bug.  It requires there are two
or more quoted lines just above the unquoted line to be filled,
and the last quoted line has two or more >'s.  Interesting.

> The quick brown fox jumps over the lazy dog.
>> The quick brown fox jumps over the lazy dog.
The quick brown fox jumps over the lazy dog.  The quick brown fox jumps over 
the lazy dog.