Devel::SimpleTrace (3pm)

Version 0.08

On the command-line:

    perl -wMDevel::SimpleTrace program_with_strange_errors.pl

Inside a module:

use Devel::SimpleTrace;

This module can be used to more easily spot the place where a program or a module generates errors. Its use is extremely simple, reduced to just \*(C`use\*(C'ing it.

This is achieved by modifying the functions \*(C`warn()\*(C' and \*(C`die()\*(C' in order to replace the standard messages by complete stack traces that precisely indicates how and where the error or warning occurred. Other than this, their use should stay unchanged, even when using \*(C`die()\*(C' inside \*(C`eval()\*(C'.

Options can be set at import time using:

perl -wMDevel::SimpleTrace=option1,option2

or

use Devel::SimpleTrace qw(option1 option2);

Available options are: Using this option will tell \*(C`Devel::SimpleTrace\*(C' to stringify objects and references passed in argument to \*(C`die()\*(C'. This option is disabled by default in order to leave objects and references untouched.

For example, \*(C`HTTP::Proxy\*(C' 0.14 suffered from strange warnings, and its author Philippe Bruhat had a hard time trying to understand where they could come from.

getsockname() on closed socket Symbol::GEN7 at /System/Library/Perl/darwin/IO/Socket.pm line 186. Use of uninitialized value in numeric ne (!=) at /Library/Perl/HTTP/Daemon.pm line 53.

Hmm.. There's obviously something wrong here, but spotting the right line is not easy.

Re-running the same script, unchanged, by just adding \*(C`-MDevel::SimpleTrace\*(C' to \*(C`perl\*(C' arguments produces the following output:

getsockname() on closed socket Symbol::GEN7 at IO::Socket::sockname(/System/Library/Perl/darwin/IO/Socket.pm:186) at IO::Socket::INET::sockport(/System/Library/Perl/IO/Socket/INET.pm:231) at HTTP::Daemon::url(/Library/Perl/HTTP/Daemon.pm:52) at HTTP::Daemon::ClientConn::get_request(/Library/Perl/HTTP/Daemon.pm:139) at HTTP::Proxy::serve_connections(/Library/Perl/HTTP/Proxy.pm:500) at HTTP::Proxy::start(/Library/Perl/HTTP/Proxy.pm:392) at t::Utils::fork_proxy(t/Utils.pm:72) at main::(t/50standard.t:138) Use of uninitialized value in numeric ne (!=) at HTTP::Daemon::url(/Library/Perl/HTTP/Daemon.pm:53) at HTTP::Daemon::ClientConn::get_request(/Library/Perl/HTTP/Daemon.pm:139) at HTTP::Proxy::serve_connections(/Library/Perl/HTTP/Proxy.pm:500) at HTTP::Proxy::start(/Library/Perl/HTTP/Proxy.pm:392) at t::Utils::fork_proxy(t/Utils.pm:72) at main::(t/50standard.t:138)

Aha! Much better. Finding the bug is now a trivial task \*(C`;-)\*(C'

(W) This warning occurs if you try to set an unknown option.

This module is currently not compatible with other modules that also work by overriding \*(C`die()\*(C' and \*(C`warn()\*(C', like \*(C`CGI::Carp\*(C'.

Se\*'bastien Aperghis-Tramoni <[email protected]>

Please report any bugs or feature requests to \*(C`[email protected]\*(C', or through the web interface at <https://rt.cpan.org/Public/Dist/Display.html?Name=Devel-SimpleTrace>. I will be notified, and then you'll automatically be notified of progress on your bug as I make changes.

Devel::SimpleTrace is Copyright (C)2004-2011 Se\*'bastien Aperghis-Tramoni.

This program is free software. You can redistribute it and/or modify it under the same terms as Perl itself.