Item6375: Use of uninitialized value in string eq at .../TWikiUserMapping.pm

I'm getting the following error in my apache error_log file whenever I request any topic. But the topic displays just fine:

[Mon Dec 21 17:48:53 2009] [error] [client 10.84.125.100] [Mon Dec 21 17:48:53 2009] view: Use of uninitialized value
in string eq at /Library/WebServer/Documents/twiki/lib/TWiki/Users/TWikiUserMapping.pm line 471.

Then when I attempt to edit a topic, I'm taken to the edit screen, and the changes are accepted, so TWiki seems to be working. But we also get these two errors in the apache error_log file:

[Mon Dec 21 17:49:17 2009] [error] [client 10.84.125.100] Use of uninitialized value in
string eq at /Library/WebServer/Documents/twiki/lib/TWiki/Users/TWikiUserMapping.pm
line 471., referer: http://xxx.yyy.com/wiki/Myweb/MyTopic
[Mon Dec 21 17:49:18 2009] [error] [client 10.84.125.100] Use of uninitialized value in
string eq at /Library/WebServer/Documents/twiki/lib/TWiki/Users/TWikiUserMapping.pm
line 471., referer: http://xxx.yyy.com/wiki/bin/edit/Myweb/MyTopic?t=1261446533;nowysiwyg=0

FYI, this has been reported by at least two other users in http://twiki.org/cgi-bin/view/Support/SID-00663

-- TWiki:Main/BarryLake - 22 Dec 2009

You can fix this error by making a small change to the twiki/lib/TWiki/Users/TWikiUserMapping.pm file. The offending line, as reported in the Apache error_log, is line 471:

   return 1 if $cUID eq $this->{session}->{user};

Change that to:

   return 1 if (defined $this->{session}->{user} && $cUID eq $this->{session}->{user});

That certainly fixes the errors in the Apache log, but I'm not sure if it's the correct fix, as it simply masks what might be another potential problem elsewhere. It might be worth someone's while to determine why the $this->{session}->{user} variable is not defined when perhaps it should be.

-- TWiki:Main.BarryLake - 12 May 2010

Thank you Barry! Fix looks good. I checked in in SVN trunk and 4.3 branch.

-- TWiki:Main.PeterThoeny - 12 May 2010