[WWcvs] webwork2: check that a tex output actually exists before typesetting the correct answer.

[Mike G. v. a. <we...@ma...>]

Log Message:
-----------
check that a tex output actually exists before typesetting the correct answer.
This effort is still a hack.  Problem.pm needs to be written from the ground up.

Modified Files:
--------------
    webwork2/lib/WeBWorK/ContentGenerator:
        Problem.pm

Revision Data
-------------
Index: Problem.pm
===================================================================
RCS file: /webwork/cvs/system/webwork2/lib/WeBWorK/ContentGenerator/Problem.pm,v
retrieving revision 1.225
retrieving revision 1.226
diff -Llib/WeBWorK/ContentGenerator/Problem.pm -Llib/WeBWorK/ContentGenerator/Problem.pm -u -r1.225 -r1.226
--- lib/WeBWorK/ContentGenerator/Problem.pm
+++ lib/WeBWorK/ContentGenerator/Problem.pm
@@ -384,6 +384,8 @@
 	# so we'll just deal with each case explicitly here. there's some code
 	# duplication that can be dealt with later by abstracting out tth/dvipng/etc.
 	
+	return "" unless defined(  $answerResult->{correct_value} ) and ref( $answerResult->{correct_value} );
+	
 	my $tex = $answerResult->{correct_value}->TeX;
 	
 	return "" unless defined $tex and $tex ne "";