Fixes RT 70986 and provides test

Author: timlegge

Generator.pm

@@ -1390,7 +1390,7 @@ sub escape {
       $_[0] =~ s/\\>/>/g;
     }
     if ($f & ESCAPE_ATTR) {
-      $_[0] =~ s/([^\\]|^)"/$1"/g;
+      $_[0] =~ s/(?<!\\)"/&quot;/g;
       $_[0] =~ s/\\"/"/g;
       if ($f & ESCAPE_APOS) {
       $_[0] =~ s/([^\\]|^)'/$1&apos;/g;

t/Issue-70986.t

@@ -0,0 +1,42 @@
+use Test::More qw/ tests 12 /;
+
+use XML::Generator;
+$s=XML::Generator->new( qw/ escape unescaped conformance strict pretty 2 /);
+
+my $xml = $s->testme({ message => 'x"y'});
+ok($xml eq '<testme message="x&quot;y" />');
+
+$xml = $s->testme({ message => 'x\"y'});
+ok($xml eq '<testme message="x"y" />');
+
+$xml = $s->testme({ message => 'x""y' });
+ok($xml eq '<testme message="x&quot;&quot;y" />');
+
+$xml = $s->testme({ message => '"x""y' });
+ok($xml eq '<testme message="&quot;x&quot;&quot;y" />');
+
+$xml = $s->testme({message => 'x"\"y'});
+ok($xml eq '<testme message="x&quot;"y" />');
+
+$xml = $s->testme({message => 'x\"\"y'});
+ok($xml eq '<testme message="x""y" />');
+
+$s=XML::Generator->new( qw/ escape always conformance strict pretty 2 /);
+$xml = $s->testme({ message => 'x"y'});
+ok($xml eq '<testme message="x&quot;y" />');
+
+$xml = $s->testme({ message => 'x\"y'});
+ok($xml eq '<testme message="x\&quot;y" />');
+
+$xml = $s->testme({ message => 'x""y' });
+ok($xml eq '<testme message="x&quot;&quot;y" />');
+
+$xml = $s->testme({ message => '"x""y' });
+ok($xml eq '<testme message="&quot;x&quot;&quot;y" />');
+
+$xml = $s->testme({message => 'x"\"y'});
+ok($xml eq '<testme message="x&quot;\&quot;y" />');
+
+$xml = $s->testme({message => 'x\"\"y'});
+ok($xml eq '<testme message="x\&quot;\&quot;y" />');
+done_testing;