bug#5122: Mismatched parentheses when dealing with huge buffer content

bug#5122: Mismatched parentheses when dealing with huge buffer content

[Deniz Dogan]

In GNU Emacs 23.1.1 (i386-mingw-nt6.0.6002)
 of 2009-07-30 on SOFT-MJASON
Windowing system distributor `Microsoft Corp.', version 6.0.6002
configured using `configure --with-gcc (4.4)'

Important settings:
  value of $LC_ALL: nil
  value of $LC_COLLATE: nil
  value of $LC_CTYPE: nil
  value of $LC_MESSAGES: nil
  value of $LC_MONETARY: nil
  value of $LC_NUMERIC: nil
  value of $LC_TIME: nil
  value of $LANG: en
  value of $XMODIFIERS: nil
  locale-coding-system: cp1252
  default-enable-multibyte-characters: t

Major mode: Lisp Interaction

Minor modes in effect:
  shell-dirtrack-mode: t
  rcirc-track-minor-mode: t
  diff-auto-refine-mode: t
  yas/global-mode: t
  yas/minor-mode: t
  global-auto-complete-mode: t
  auto-complete-mode: t
  cua-mode: t
  tooltip-mode: t
  mouse-wheel-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  global-auto-composition-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  column-number-mode: t
  line-number-mode: t
  transient-mark-mode: t

Recent input:
C-v C-v C-v C-v C-v C-v C-v C-v C-v C-v C-v C-v C-v
C-v C-v C-v C-v C-v C-v C-v C-v C-v C-v C-v C-v C-v
C-v C-v C-v C-v C-v C-v C-v C-v C-v C-v C-v C-v C-v
C-v C-v C-v C-v C-v C-v C-v C-v C-v C-v C-v C-v C-v
M-k C-n <C-return> M-f C-g C-g <C-return> C-f C-f C-f
C-f C-f C-f C-f C-f C-f C-f C-f C-f C-f C-f C-f C-f
C-f C-f C-f C-f C-f C-f C-f C-f C-v C-v C-v C-v C-v
C-v C-v C-v C-v C-v C-v C-v C-v C-v C-v C-v C-v C-v
C-v C-v C-v C-v C-v C-v C-v C-v C-v C-v C-v C-v C-v
C-v C-v C-v C-v C-v C-v C-v C-v C-v C-v C-v C-v C-v
C-v C-v C-v C-v C-v C-v C-v C-v C-v C-v C-v C-v C-v
C-v C-v C-v C-v C-v C-v C-v C-v C-v C-v C-v C-v C-v
C-v C-v C-v C-v C-v C-v C-v M-v M-v M-v M-v M-v M-v
M-v M-v M-v M-v C-v C-n C-n C-n C-n C-n C-n C-n C-n
C-n C-n C-n C-n C-n C-n C-n C-n C-n C-n C-n C-n C-n
C-n C-n C-n C-n C-n C-n C-n C-n C-n C-n C-n C-n C-n
C-n C-n C-n C-n C-n C-n C-n C-n C-n C-n C-n C-n C-n
C-n C-n C-n C-n C-n C-n C-n M-k C-g M-< C-n C-p M-n
C-p C-e <backspace> ) C-t C-s M-< M-n M-v <down-mouse-1>
<mouse-movement> <down-mouse-4> <drag-mouse-1> C-t
o C-t C-g C-h v <up> <return> C-n C-n C-n C-t o C-n
C-n C-n C-n C-n C-n C-n C-SPC M-n M-w C-t o C-t u s
c r a <return> C-y M-< C-n C-n M-> C-p C-e <backspace>
) M-x r e p o r t - e m a c s <tab> <return>

When taking the value of ucs-completions given by C-h v
ucs-completions and inserting it in the scratch buffer, Emacs is
unable to determine that a correct parentheses match is made. (Pardon
my English.) I simply remove the last of the two trailing parentheses
of the expression and insert a new trailing parenthesis (making the
content identical to what it was initially), and I get "Mismatched
parentheses".

-- 
Deniz Dogan

bug#5122: Mismatched parentheses when dealing with huge buffercontent

[Drew Adams]

See option `blink-matching-paren-distance' and node Matching in the Emacs
manual.

Does increasing that variable's value resolve the problem? 

bug#5122: Mismatched parentheses when dealing with huge buffercontent

[Deniz Dogan]

2009/12/4 Drew Adams <drew.adams@oracle.com>:
> See option `blink-matching-paren-distance' and node Matching in the Emacs
> manual.
>
> Does increasing that variable's value resolve the problem?
>
>

Yes, it does solve the problem.

-- 
Deniz Dogan

bug#5122: Mismatched parentheses when dealing with huge buffercontent

[Drew Adams]

> > See option `blink-matching-paren-distance' and node 
> > Matching in the Emacs manual.
> > Does increasing that variable's value resolve the problem?
> 
> Yes, it does solve the problem.

It's not real obvious when you see mismatch highlighting (and are used to it
working) that the highlighting might not mean a mismatch at all, but just an
insufficiently large option value. Many (most?) users will not even guess that
there is such an option.

Perhaps we could use a :help-echo property along with the mismatch highlight
face, pointing to the option?

bug#5122: Mismatched parentheses when dealing with huge buffercontent

[Deniz Dogan]

2009/12/5 Drew Adams <drew.adams@oracle.com>:
>> > See option `blink-matching-paren-distance' and node
>> > Matching in the Emacs manual.
>> > Does increasing that variable's value resolve the problem?
>>
>> Yes, it does solve the problem.
>
> It's not real obvious when you see mismatch highlighting (and are used to it
> working) that the highlighting might not mean a mismatch at all, but just an
> insufficiently large option value. Many (most?) users will not even guess that
> there is such an option.
>
> Perhaps we could use a :help-echo property along with the mismatch highlight
> face, pointing to the option?
>
>

I'm not sure what the best solution would be, but it is indeed strange
that Emacs says that there was a parenthesis *mismatch*. Maybe it
would be better to say something along the lines of "Emacs was unable
to find a matching parenthesis in the previous X characters", but
obviously much more terse.

bug#5122: Mismatched parentheses when dealing with huge buffercontent

[Eli Zaretskii]

> From: "Drew Adams" <drew.adams@oracle.com>
> Date: Fri, 4 Dec 2009 16:31:51 -0800
> Cc: emacs-pretest-bug@gnu.org, 5122@emacsbugs.donarmstrong.com
> 
> It's not real obvious when you see mismatch highlighting (and are used to it
> working) that the highlighting might not mean a mismatch at all, but just an
> insufficiently large option value. Many (most?) users will not even guess that
> there is such an option.
> 
> Perhaps we could use a :help-echo property along with the mismatch highlight
> face, pointing to the option?

help-echo is not guaranteed to be seen, and could be tricky when
there's an important message in the echo area (especially if the
help-echo itself is displayed in the echo area).  Also, it will not
work on a text terminal.

I think it's better to modify the echo area message, such that if
Emacs hits the blink-matching-paren-distance limit (as opposed to
hitting point-min), the message says something like

  Mismatched parentheses (within blink-matching-paren-distance)

bug#5122: Mismatched parentheses when dealing with huge buffercontent

[Drew Adams]

> > It's not real obvious when you see mismatch highlighting 
> (and are used to it
> > working) that the highlighting might not mean a mismatch at 
> all, but just an
> > insufficiently large option value. Many (most?) users will 
> not even guess that
> > there is such an option.
> > 
> > Perhaps we could use a :help-echo property along with the 
> mismatch highlight
> > face, pointing to the option?
> 
> help-echo is not guaranteed to be seen, and could be tricky when
> there's an important message in the echo area (especially if the
> help-echo itself is displayed in the echo area).  Also, it will not
> work on a text terminal.
> 
> I think it's better to modify the echo area message, such that if
> Emacs hits the blink-matching-paren-distance limit (as opposed to
> hitting point-min), the message says something like
> 
>   Mismatched parentheses (within blink-matching-paren-distance)

Yes that sounds good too.

To be honest, I don't know if I ever noticed any message in the echo area for
this. Perhaps because the message was so expected I never paid any attention to
it.