[Templates] Template::Plugin::Class & use diagnostics

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My application just fell over with long error messages like that at the 
bottom of the message. I think I've tracked the problem down to the most 
excellent Template::Plugin::Class (v0.12). It tries to load the class 
you've asked to use and decides whether it found an error with an RE:

   12  # stolen from base.pm
   13  eval "require $arg";
   14  # Only ignore "Can't locate" errors from our eval require.
   15  # Other fatal errors (syntax etc) must be reported.
   16  die if $@ && $@ !~ /^Can't locate .*? at \(eval /;

My immediate problem is that I'd just included something in my 
application that included a 'use diagnostics' statement. Now this 
reformats normal error messgaes so that

Can't locate QD1/BioDatabase.pm in @INC (@INC contains: 
/home/dhoworth/progs/modules /home/dhoworth/progs/maypole 
/usr/local/lib/perl/5.6.1 /usr/local/share/perl/5.6.1 /usr/lib/perl5 
/usr/share/perl5 /usr/lib/perl/5.6.1 /usr/share/perl/5.6.1 
/usr/local/lib/site_perl .) at (eval 48) line 3.

becomes

Uncaught exception from user code:
	Can't locate QD1/BioDatabase.pm in @INC (@INC contains: 
/home/dhoworth/progs/modules /home/dhoworth/progs/maypole 
/usr/local/lib/perl/5.6.1 /usr/local/share/perl/5.6.1 /usr/lib/perl5 
/usr/share/perl5 /usr/lib/perl/5.6.1 /usr/share/perl/5.6.1 
/usr/local/lib/site_perl .) at (eval 48) line 3.

and consequently T-P-C's RE fails to match it and T-P-C dies. It could 
be fixed just by removing the start of string anchor '^' but I think it 
could also be improved a little further using some code I adapted from 
Class::DBI:

--- Template/Plugin/Class.pm
+++ Template/Plugin/Class-new.pm
@@ -13,7 +13,8 @@
      eval "require $arg";
      # Only ignore "Can't locate" errors from our eval require.
      # Other fatal errors (syntax etc) must be reported.
-    die if $@ && $@ !~ /^Can't locate .*? at \(eval /;
+    (my $filename = $arg) =~ s!::!/!g;
+    die if $@ && $@ !~ /Can't locate \Q$filename\E\.pm/;
      no strict 'refs';
      unless (%{"$arg\::"}) {
          require Carp;

That removes the start of string anchor so it works with use diagnostics 
and it also checks which module failed so that a disaster in a use 
statement within the required class is not ignored.

Cheers, Dave

The error message was:

Uncaught exception from user code:
	file error - Uncaught exception from user code:
	undef error - Uncaught exception from user code:
	undef error - Uncaught exception from user code:
	file error - Uncaught exception from user code:
	undef error - Uncaught exception from user code:
	undef error - Uncaught exception from user code:
	plugin error - Uncaught exception from user code:
	Uncaught exception from user code:
	Can't locate QD1/BioDatabase.pm in @INC (@INC contains: 
/home/dhoworth/progs/modules /home/dhoworth/progs/maypole 
/usr/local/lib/perl/5.6.1 /usr/local/share/perl/5.6.1 /usr/lib/perl5 
/usr/share/perl5 /usr/lib/perl/5.6.1 /usr/share/perl/5.6.1 
/usr/local/lib/site_perl .) at (eval 48) line 3.
	eval 'require QD1::BioDatabase
;' called at /usr/local/share/perl/5.6.1/Template/Plugin/Class.pm line 13
	Template::Plugin::Class::new('Template::Plugin::Class', 
'Template::Context=HASH(0x88a1044)', 'QD1::BioDatabase') called at 
/usr/local/lib/perl/5.6.1/Template/Plugins.pm line 119
	eval {...} called at /usr/local/lib/perl/5.6.1/Template/Plugins.pm line 113
	Template::Plugins::fetch('Template::Plugins=HASH(0x88a1164)', 'Class', 
'ARRAY(0x8a1f5bc)', 'Template::Context=HASH(0x88a1044)') called at 
/usr/local/lib/perl/5.6.1/Template/Context.pm line 191
	Template::Context::plugin('Template::Context=HASH(0x88a1044)', 'Class', 
'ARRAY(0x8a1f5bc)') called at /var/www/qd1/custom/addnew.tt line 7
	eval {...} called at /var/www/qd1/custom/addnew.tt line 7
MANY MORE LINES DELETED


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