bug#17190: 24.4.50; fill-flow checks quoted lines after deleting leading space

bug#17190: 24.4.50; fill-flow checks quoted lines after deleting leading space

[Kazuhiro Ito]

When I evaluate the below code, I receive unexpected result.

(with-temp-buffer
  (require 'flow-fill)
  (insert " > ABC \nDEF\n")
  (fill-flowed)
  ;; (mime-display-text/plain-flowed)
  (buffer-string))

->
"> ABC 
DEF
"
But I expect the below result.

"> ABC DEF
"

-- 
Kazuhiro Ito

bug#17190: 24.4.50; fill-flow checks quoted lines after deleting leading space

[Lars Ingebrigtsen]

Kazuhiro Ito <kzhr@d1.dion.ne.jp> writes:

> When I evaluate the below code, I receive unexpected result.
>
> (with-temp-buffer
>   (require 'flow-fill)
>   (insert " > ABC \nDEF\n")
>   (fill-flowed)
>   ;; (mime-display-text/plain-flowed)
>   (buffer-string))
>
> ->
> "> ABC 
> DEF
> "
> But I expect the below result.
>
> "> ABC DEF
> "

If I'm reading

https://tools.ietf.org/html/rfc2646

right, that's not how this is supposed to work, and `fill-flowed' does
it correctly -- it's supposed to flow together lines that have the same
quotation level, like this:

(with-temp-buffer
  (require 'flow-fill)
  (insert " > ABC \n> DEF\n")
  (fill-flowed)
  (buffer-string))


-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no

bug#17190: 24.4.50; fill-flow checks quoted lines after deleting leading space

[Kazuhiro Ito]

> > When I evaluate the below code, I receive unexpected result.
> >
> > (with-temp-buffer
> >   (require 'flow-fill)
> >   (insert " > ABC \nDEF\n")
> >   (fill-flowed)
> >   ;; (mime-display-text/plain-flowed)
> >   (buffer-string))
> >
> > ->
> > "> ABC 
> > DEF
> > "
> > But I expect the below result.
> >
> > "> ABC DEF
> > "
> 
> If I'm reading
> 
> https://tools.ietf.org/html/rfc2646
> 
> right, that's not how this is supposed to work, and `fill-flowed' does
> it correctly -- it's supposed to flow together lines that have the same
> quotation level, like this:

Please beware Space-Stuffing at the first line.  The first line is not
quoted one.  " > ABC " and "DEF" have the same quotation level.

-- 
Kazuhiro Ito

bug#17190: 24.4.50; fill-flow checks quoted lines after deleting leading space

[Lars Ingebrigtsen]

Kazuhiro Ito <kzhr@d1.dion.ne.jp> writes:

> Please beware Space-Stuffing at the first line.  The first line is not
> quoted one.  " > ABC " and "DEF" have the same quotation level.

Ah, I missed that bit.  And:

4.4.  Space-Stuffing

   In order to allow for unquoted lines which start with ">", and to
   protect against systems which "From-munge" in-transit messages
   (modifying any line which starts with "From " to ">From "),
   Format=Flowed provides for space-stuffing.

   Space-stuffing adds a single space to the start of any line which
   needs protection when the message is generated.  On reception, if the
   first character of a line is a space, it is logically deleted.  This
   occurs after the test for a quoted line, and before the test for a
   flowed line.

So `fill-flowed' is definitely doing this wrong -- it just deletes the
space stuffing before it does any of the processing, which is the
opposite of what it should do, really.

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no

bug#17190: 24.4.50; fill-flow checks quoted lines after deleting leading space

[Lars Ingebrigtsen]

Lars Ingebrigtsen <larsi@gnus.org> writes:

> So `fill-flowed' is definitely doing this wrong -- it just deletes the
> space stuffing before it does any of the processing, which is the
> opposite of what it should do, really.

I've now reimplemented the function to follow the algorithm proposed by
the RFC more closely in Emacs 27.

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no

bug#17190: 24.4.50; fill-flow checks quoted lines after deleting leading space

[Kazuhiro Ito]

> > So `fill-flowed' is definitely doing this wrong -- it just deletes the
> > space stuffing before it does any of the processing, which is the
> > opposite of what it should do, really.
> 
> I've now reimplemented the function to follow the algorithm proposed by
> the RFC more closely in Emacs 27.

I confirmed the problem was fixed.
Thank you!

-- 
Kazuhiro Ito