bug#6343: Log-edit font lock changes lead to loop

bug#6343: Log-edit font lock changes lead to loop

[Chong Yidong]

I had the following text in my kill ring:

  * cedet/semantic/lex-spp.el
  (semantic-lex-spp-table-write-slot-value): Instead of erroring on
  invalid values during save, just save a nil (Bug#6324).

From VC-dir, I marked some files and typed "v" to commit them.  In the
log edit buffer, I type "C-y" to attempt to yank into the buffer.  Emacs
became unresponsive to all keyboard input.  According to the debugger,
Emacs is looping on `jit-lock-fontify-now'.


If I revert the following change, the problem goes away.

22010-06-02  Dan Nicolaescu  <dann@ics.uci.edu>

  * log-edit.el (log-edit-font-lock-keywords): Make group 4 match lax.

This is on an up-to-date trunk build:

GNU Emacs 24.0.50.1 (i686-pc-linux-gnu, GTK+ Version 2.20.1)
 of 2010-06-03 on furry

bug#6343: Log-edit font lock changes lead to loop

[Dan Nicolaescu]

Chong Yidong <cyd@stupidchicken.com> writes:

> I had the following text in my kill ring:
>
>   * cedet/semantic/lex-spp.el
>   (semantic-lex-spp-table-write-slot-value): Instead of erroring on
>   invalid values during save, just save a nil (Bug#6324).
>
> From VC-dir, I marked some files and typed "v" to commit them.  In the
> log edit buffer, I type "C-y" to attempt to yank into the buffer.  Emacs
> became unresponsive to all keyboard input.  According to the debugger,
> Emacs is looping on `jit-lock-fontify-now'.
>
>
> If I revert the following change, the problem goes away.
>
> 22010-06-02  Dan Nicolaescu  <dann@ics.uci.edu>
>
>   * log-edit.el (log-edit-font-lock-keywords): Make group 4 match lax.

The motivation for the above change was that the *Messages* would get a lot of errors of the form:
(from memory, so the wording is not exactly this)

Error in redisplay, could not match (4 font-lock-warning-face)

bug#6343: Log-edit font lock changes lead to loop

[Juanma Barranquero]

On Thu, Jun 3, 2010 at 19:17, Chong Yidong <cyd@stupidchicken.com> wrote:

> In the
> log edit buffer, I type "C-y" to attempt to yank into the buffer.  Emacs
> became unresponsive to all keyboard input.

I've seen the same problem just by typing

  bla bla blah

then moving the point to the beginning of line and trying to add
"somefile: ", i.e.

 somefile[ ]blah blah blah

[ ] marks the point. Emacs blocks when trying to type `:'.

> If I revert the following change, the problem goes away.

Same here.

    Juanma

bug#6343: Log-edit font lock changes lead to loop

[Lennart Borgman]

On Fri, Jun 4, 2010 at 3:40 AM, Juanma Barranquero <lekktu@gmail.com> wrote:
> On Thu, Jun 3, 2010 at 19:17, Chong Yidong <cyd@stupidchicken.com> wrote:
>
>> In the
>> log edit buffer, I type "C-y" to attempt to yank into the buffer.  Emacs
>> became unresponsive to all keyboard input.
>
> I've seen the same problem just by typing

A little bit off-topic: you mean you can't even stop with C-g?

How do you normally handle that? (I put some limit on all font lock
loops in my code ... ;-) )

bug#6343: Log-edit font lock changes lead to loop

[Juanma Barranquero]

On Fri, Jun 4, 2010 at 04:12, Lennart Borgman <lennart.borgman@gmail.com> wrote:

> A little bit off-topic: you mean you can't even stop with C-g?

C-g acts weird. It stops, sort of, but then moving around makes Emacs
loop again.

> How do you normally handle that? (I put some limit on all font lock
> loops in my code ... ;-) )

You'll have to be a bit more specific.

    Juanma

bug#6343: Log-edit font lock changes lead to loop

[Lennart Borgman]

On Fri, Jun 4, 2010 at 12:15 PM, Juanma Barranquero <lekktu@gmail.com> wrote:
> On Fri, Jun 4, 2010 at 04:12, Lennart Borgman <lennart.borgman@gmail.com> wrote:
>
>> A little bit off-topic: you mean you can't even stop with C-g?
>
> C-g acts weird. It stops, sort of, but then moving around makes Emacs
> loop again.


I did not notice that it stops first. Strange.


>> How do you normally handle that? (I put some limit on all font lock
>> loops in my code ... ;-) )
>
> You'll have to be a bit more specific.


I just do something like this in case I make a stupid error somewhere:

(defsubst visual-indent-while (limit counter where)
  (let ((count (symbol-value counter)))
    (if (= count limit)
        (progn
          (message "Reached (while limit=%s, where=%s)" limit where)
          nil)
      (set counter (1+ count)))))

        (while (and (visual-indent-while 200 'n-while
"visual-indent-jit-lock-fun")
                    (< (point) bound)) ;; Max bound = (point-max)

bug#6343: Log-edit font lock changes lead to loop

[Glenn Morris]

Looks like this was fixed by your 2010-06-12 change to log-edit.