Bug #27713 for Cwd: Two discrepancies with realpath() utility

I discovered two discrepancies between Cwd::realpath() and the realpath utility. IMHO, the behaviour of the utility is correct and that of Cwd::realpath() wrong in both cases. The inclusion of 'use strict;' etc. in the examples below is to make the point that the returned value is 'undef', not merely the empty string, which would be at least as bad, of course. Versions of perl and Cwd: ------------------------- $ uname -a Linux scrat 2.6.20-16-generic #2 SMP Thu Jun 7 19:00:28 UTC 2007 x86_64 GNU/Linux $ perl --version | grep ^This This is perl, v5.8.8 built for x86_64-linux-gnu-thread-multi $ perl -MCwd -e 'print "$Cwd::VERSION\n"' 3.12 $ # END Discrepancies: -------------- 1. If Cwd::realpath() is invoked with an argument which is an unsearchable (execute bit clear) directory, it returns undef. This is contrary to expectation and the behaviour of the realpath utility which (correctly IMO) returns the full path of the directory. The full path of a directory has nothing to do with the searchability of that directory itself, so Cwd is wrong and the utility is right in this case. Reproduce with: $ cd /tmp $ mkdir foo $ chmod u-x foo $ realpath ./foo /tmp/foo $ perl -MCwd -we 'use strict; my $p=Cwd::realpath("./foo"); print "$p\n";' Use of uninitialized value in concatenation (.) or string at -e line 1. $ # END 2. If Cwd::realpath is invoked on a dangling symlink where the directory name of the target exists, it returns the (non-existant) target of the symlink. This is contrary to the behaviour of the realpath utility, which returns an error for all dangling symlinks, and is inconsistent with Cwd::realpath()'s own behaviour when the "dirname" of the target does not exist. IMHO, Cwd::realpath() should return 'undef' or the (non-existant) target consistently for all dangling symlinks and not return different results depending on whether the directory-part of the symlink target exists or not. Reproduce with: $ cd /tmp $ rm -f bar $ ln -s bar foo $ realpath ./foo ./foo: No such file or directory $ perl -MCwd -we "use strict; my \$p=Cwd::realpath('./foo'); print \"\$p\n\";" /tmp/bar $ # END However, when the "dirname" of the target does not exist, the behaviour is different: $ ln -sf /this/does/not/exist foo $ realpath ./foo ./foo: No such file or directory $ perl -MCwd -we "use strict; my \$p=Cwd::realpath('./foo'); print \"\$p\n\";" Use of uninitialized value in concatenation (.) or string at -e line 1. $ # END