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Postings from March 2007
On 3/7/07, demerphq <demerphq@gmail.com> wrote:
> The change required to lib/ExtUtils/Liblist/Kid.pm fixes a bug in it
> that was detected by the require_tie_mod() failures, but was not
> actually related to it. The cause was that m-[\w$\-]- matches the same
> as /[\w$-]/ and not /[\w$\-]/ as I guess the author expected.
- if (($locspec,$type) = $lib =~ m-^([\w$\-]+)(/\w+)?- and
$locspec =~ /perl/i) {
+ if (($locspec,$type) = $lib =~ m!^([\w$\-]+)(/\w+)?! and
$locspec =~ /perl/i) {
The code you changed in _vms_ext() has been as it was for many years
(like 9, 10, maybe more) and has never caused any trouble I'm aware
of, though I agree it does not seem to do what it was intended to.
After your change it now always generates the following warning:
Use of uninitialized value $\ in regexp compilation at
../../../../lib/ExtUtils/Liblist/Kid.pm line 392.
easily reproducible like so since $\ is undef by default:
$ perl -we "print $1 if 'foo$bar-baz' =~ m!([\w$\-]+)!;"
Use of uninitialized value $\ in regexp compilation at -e line 1.
foo
Replacing "-" with "!" as the match delimiter changed the
interpretation of C<$\-> so that the backslash no longer escapes the
minus sign but now sidles up to the dollar sign to function as the
special variable C<$\>. Whereas before we were inadvertently getting
the special variable C<$-> interpolated, we are now inadvertently
getting the special variable C<$\> interpolated. The default value of
C<$-> is zero, so there was no uninitialized value warning the old
way, but C<$\> defaults to undef and causes the warning. You can
confirm all this by running one-liners under -Dr and seeing what regex
you're really getting.
I'm pretty sure the original intention for the character class was to
match word characters, dollar signs and minus signs, not word
characters, a special variable, and minus signs. The clue is that
dollar signs appear quite frequently in system-supplied library names
on VMS, and that is what this bit of code is working with.
I think all we need is to escape the dollar sign and use a match
delimiter that doesn't appear in the regex:
$ perl -we "print qq/$1,$2\n/ if 'foo$bar-baz/share' =~ m|^([\w\$-]+)(/\w+)?|;"
foo$bar-baz,/share
I will test this in Kid.pm and see what else breaks as a result of
fixing it :-(.
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