log4perl-devel

[log4perl-devel] Bug while using Log::Dispatch::File

[<Msc...@ao...>]

Hi Kevin and Dave,

there seems to be a weird bug with Log::Log4perl and Log::Dispatch::File. The 
application I'm using it with produces a lot of multi-line DEBUG messages and 
in certain circumstances this will overwrite (!) previously written (!) 
sections of the log file.
Looks like the file handle gets confused and suddenly jumps back. 
Using Log::Dispatch::Screen instead doesn't show the problem. 
Dave, is there any limitations to Log::Dispatch::File you can think of?

My suspicion is that this is caused by our closures holding references to the 
Log::Dispatch::File object(s) which is/are using a "local"ized filehandle 
instead of a $fh scalar variable (open my $fh, ">blah") to keep track of the 
opened file.

I don't have an easy-to-reproduce test case yet, just to give you guys a 
heads-up and maybe you already know where to look for? 

-- Mike

Mike Schilli
log...@pe...
http://perlmeister.com
http://log4perl.sourceforge.net

[log4perl-devel] Re: Bug while using Log::Dispatch::File

[Dave R. <au...@ur...>]

On Fri, 30 Aug 2002 Msc...@ao... wrote:

> Using Log::Dispatch::Screen instead doesn't show the problem.
> Dave, is there any limitations to Log::Dispatch::File you can think of?

Not that I know of.  This is the first I've heard of such a problem.

> My suspicion is that this is caused by our closures holding references to the
> Log::Dispatch::File object(s) which is/are using a "local"ized filehandle
> instead of a $fh scalar variable (open my $fh, ">blah") to keep track of the
> opened file.

Actually, the filehandle in Log::Dispatch::File is lexical.  The 'local'
bit in the code is just a Perl trick to get a filehandle into a scalar in
Perl 5.005 and earlier.

I can't imagine why closures would be a problem.

> I don't have an easy-to-reproduce test case yet, just to give you guys a
> heads-up and maybe you already know where to look for?

Without a test case I'm at a loss.  Log::Dispatch::File is barely 100
lines of code.  Not that I can't manage to fit a few bugs in there, but it
really is simple stuff so I don't see how this could be happening.


-dave

/*==================
www.urth.org
we await the New Sun
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Re: [log4perl-devel] Bug while using Log::Dispatch::File

[Erik W. S. <er...@se...>]

Could you have a \r in the log format? Without a \n after, it will cause 
the current line to be overwritten (or to appear overwritten when 
displayed in things like less and more).

-e


Msc...@ao... wrote:

> Hi Kevin and Dave,
>
> there seems to be a weird bug with Log::Log4perl and 
> Log::Dispatch::File. The application I'm using it with produces a lot 
> of multi-line DEBUG messages and in certain circumstances this will 
> overwrite (!) previously written (!) sections of the log file.
> Looks like the file handle gets confused and suddenly jumps back.
> Using Log::Dispatch::Screen instead doesn't show the problem.
> Dave, is there any limitations to Log::Dispatch::File you can think of?
>
> My suspicion is that this is caused by our closures holding references 
> to the Log::Dispatch::File object(s) which is/are using a "local"ized 
> filehandle instead of a $fh scalar variable (open my $fh, ">blah") to 
> keep track of the opened file.
>
> I don't have an easy-to-reproduce test case yet, just to give you guys 
> a heads-up and maybe you already know where to look for?
>
> -- Mike
>
> Mike Schilli
> log...@pe...
> http://perlmeister.com
> http://log4perl.sourceforge.net