No, it's not a bug. check carefully what's the difference between \z and \Z. and check the following samples: 
perl -e 'print "match\n" if "foo\n" =~ /.*\z/'
perl -e 'print "match\n" if "foo\n" =~ /.*\Z/'
perl -e 'print "match\n" if "foo\n\n\n" =~ /.*\Z/'

[download]
Update: the third one matches just coz of .* in use. \Z can not keep multiple newlines.

Regards,
Xicheng

In reply to Re^2: Strange regex to test for newlines: /.*\z/ by xicheng
in thread Strange regex to test for newlines: /.*\z/ by betterworld

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