Re: (file-error "writing to process" "bad address" #<process imap>) when Gcc-ing a group

[David Engster <deng@randomsample.de>]

David Engster <deng@randomsample.de> writes:
> Tassilo Horn <tassilo@member.fsf.org> writes:
>> David Engster <deng@randomsample.de> writes:
>>> I have no idea if this is a problem with Dovecot or maybe a bug in
>>> process-send-region or in send-region (I don't see how any other Gnus
>>> or Emacs code could be involved in this).
>>
>> `send-region' is only an alias for `process-send-region'.
>
> Sorry, I should have said "send-region in process.c". The file-error is
> thrown there, in the C source.

Make that "send_process"...

>> Maybe we could create an isolated test case which doesn't involve gnus
>> and dovecot. I tried to create such a case, but I don't have enough
>> time right now.  Basically it should be possible to load a big file
>> into a temp buffer and use it as input to a `cat' process, or
>> something like that and then compare if the result equals the input.
>
> I'd be surprised if the error is that general; much more people would
> have to see it in this case.

Well, color me surprised. I was just able to provoke the error with
the procedure you suggested:

(setq numlines 500000)

(progn
  (setq proctest 
	(start-process "cat" (get-buffer-create "cat") "/bin/cat"))
  (with-temp-buffer
    (dotimes (dummy numlines)
      (insert 
       (concat (number-to-string (random))
	       (number-to-string (random))
	       (number-to-string (random))
	       (number-to-string (random))
	       "\n")))
    (process-send-region proctest (point-min) (point-max)))
  (delete-process proctest))

And sometimes(!) I get:

Debugger entered--Lisp error: (file-error "writing to process" "bad address" #<process cat>)
  process-send-region(#<process cat> 1 18672117)

using Emacs from CVS (2009-02-04) on Darwin/Mac OS X. 

The error doesn't always happen. I usually have to repeat the procedure
several times until it occurs. You can increase 'numlines' to make it
more likely. It might also be that it depends on the load of the system
or something like that.

Maybe this

http://emacsbugs.donarmstrong.com/cgi-bin/bugreport.cgi?bug=471

might also be connected to this issue.

-David