Issue with Unicode identifier

[michal-josef-spacek]

I found the issue with Unicode identifiers in Graph (See michal-josef-spacek/Map-Tube-Sofia#4).
This is a regression between Graph 0.9715 and 0.9716.

Reproducer:

#!/usr/bin/env perl

use strict;
use warnings;

use Graph;
use Unicode::UTF8 qw(decode_utf8 encode_utf8);

my $g = Graph->new;
$g->add_edge('A', decode_utf8('Říp'));
$g->add_edge(decode_utf8('Říp'), 'B');

print encode_utf8($g)."\n";

print 'is_weakly_connected: '.$g->is_weakly_connected."\n";

Output:

A-Říp,Říp-B
is_weakly_connected:

Expected value of is_weakly_connected() is 1.

I found that the issue is random. Sometimes returns 1.

The same issue is with the Encode Perl module usage or use utf8 usage.