Log::Dispatch::File should not explicitly close the filehandle; rely on garbage collection instead

[damil]

If a logger is cloned, it will hold a copy of the logging filehandle. When the clone is destroyed, Log::Dispatch::File should not close the filehandle, because the original logger object might still be alive. Instead of an explicit close, just rely on the garbage collector : it will automatically close the file when the last reference is destroyed.

Below is a simple demonstration of the problem :

use Log::Dispatch;
use Clone qw(clone);

my $obj = {log => Log::Dispatch->new(outputs => [
  ['Screen', min_level => 'debug', newline => 1                          ],
  ['File',   min_level => 'debug', newline => 1, filename => 'foobar.log'],
 ])};
my $clone = clone $obj;
$obj->{log}->info('cloned');
undef $clone;
$obj->{log}->info('after delete');

This produces an error "print() on closed filehandle"

[autarch]

I'm a little nervous about changing this after all these years. I wonder if any code out there somehow relies on the current behavior.

[damil]

Well, for clients who do not clone the logger, there should be no difference : when the garbage collector destroys the logger object, the filehandle will be closed automatically (if that was the last reference to that filehandle).

If that filehandle was copied somehow, but the logger closes the filehandle at DESTROY(), then that copy is useless, so I strongly doubt that any code out there would be affected.

However, to be on the safe side, maybe there could be an option at logger creation for controlling what will happen during DESTROY(), what do you think ?

For info, here is the dirty workaround that I'm using at the moment :

# ======================================================================
# HACK HACK comme solution temporaire en attendant la résolution de https://github.com/houseabsolute/Log-Dispatch/issues/73 :
# pour éviter que Log::Dispatch::File::DESTROY referme intempestivement la filehandle de logging ... on efface la méthode DESTROY!
# Le test sur la version de Log::Dispatch fait l'hypothèse que le bug sera résolu dans la prochaine version publiée (donc > 2.71)
use Log::Dispatch::File;
use version;
if (version->parse(Log::Dispatch->VERSION) <= version->parse(2.71)) {
  # warn "MONKEY PATCHING Log::Dispatch::File\n";
  no strict 'refs';
  undef *Log::Dispatch::File::DESTROY; # efface la méthode DESTROY dans la table des symboles de Log::Dispatch::File
}
# FIN DU HACK
# ======================================================================