| Subject: | Label with newline causes infinite loop |
Hello,
If I have a label with a newline I can cause an infinite loop which eventually uses up all the
memory available to the perl interpreter. I've tested this on both 5.14.2 and 5.12.3 though at
work there is an old 5.8 version which does not exhibit this behavior.
Here is the simplest test case:
----------
#!/usr/bin/perl
use strict;
use warnings;
use Graph::Easy;
my $graph = Graph::Easy->new();
$graph->add_edge('Test1', 'Test 2');
$graph->add_edge('Test 2', "Test 3\nTest 4\nTest 5");
print $graph->as_ascii_html();
----------
The infinite loop is in Graph::Easy::Node::_aligned_label in this while loop at line 593:
while ($name ne '')
{
$name =~ s/^(.*?([^\\]|))(\z|\\(n|r|l|c))//;
...
}
The problem is that the regular expression is not matching a new line character but the two
character combinations, \n, \r, \l, and \c. I'm not sure if that was intentional, but if it was I'd
recommend changing the regex to:
$name =~ s/^(.*?([^\\]|))(\z|\n|\\([nrlc]))//;
The modifications include adding \n as a character in the last section and simplifies the
n|r|l|c to [nrlc].
If it wasn't intentional and you wanted to check for newline characters I believe you could use
the regex class \n or you could change the regex to:
$name =~ s/^(.*?([^\\]|))(\z|([\n\r\l\c]))//;