[log4perl-devel] warning on uninitialized value when logging undef

[Kevin G. <cp...@go...>]

This is kind of annoying thing that I noticed recently, if you do $logger->info($msg) and $msg is 
undefined then you get a warning:

 perl -W -Ilib -e 'use Log::Log4perl qw(:easy); Log::Log4perl->easy_init($INFO); INFO(undef)'
Use of uninitialized value in join or string at lib/Log/Log4perl/Appender.pm line 167.

and it's not even a very helpful warning since it's buried in the guts of Log4perl.

Using git bisect (neat tool) I found while I (myself even!) had fixed the issue back in 
029d7df8 in 2002, I broke it (me again!) in afb95ef7e in 2003.

Anyway, this would be the correct fix for it now, if all we're going to do is make a 
string out of it, it's ok just to use the defined bits of the mssage.

Any opinion on this?  Or should we stay with the uninitialized warning, however unhelpful it is?

diff --git a/lib/Log/Log4perl/Appender.pm b/lib/Log/Log4perl/Appender.pm
index 923836f..455fd09 100644
--- a/lib/Log/Log4perl/Appender.pm
+++ b/lib/Log/Log4perl/Appender.pm
@@ -162,10 +162,13 @@ sub log {
             #not defined, the normal case
         if (! defined $self->{warp_message} ){
                 #join any message elements
-            $p->{message} = 
-                join($Log::Log4perl::JOIN_MSG_ARRAY_CHAR, 
-                     @{$p->{message}} 
-                     ) if ref $p->{message} eq "ARRAY";
+            if (ref $p->{message} eq "ARRAY"){
+               $p->{message} = 
+                    join($Log::Log4perl::JOIN_MSG_ARRAY_CHAR,
+                        grep { defined $_ }
+                            @{$p->{message}}
+                    ); 
+            }
             
             #defined but false, e.g. Appender::DBI
         } elsif (! $self->{warp_message}) {


If nobody objects I can make a unit test for it as well and push it to Mike via github.



--
Kevin G.