Task::Weaken - Ensure that a platform has weaken support
One recurring problem in modules that use Scalar::Util's "weaken"
function is that it is not present in the pure-perl variant.
While this isn't necesarily always a problem in a straight CPAN-based
Perl environment, some operating system distributions only include the
pure-Perl versions, don't include the XS version, and so weaken is then
"missing" from the platform, despite passing a dependency on
Most notably this is RedHat Linux at time of writing, but other come and
go and do the same thing, hence "recurring problem".
The normal solution is to manually write tests in each distribution to
ensure that "weaken" is available.
This restores the functionality testing to a dependency you do once in
your Makefile.PL, rather than something you have to write extra tests
for each time you write a module.
It should also help make the package auto-generators for the various
operating systems play more nicely, because it introduces a dependency
that they have to have a proper weaken in order to work.
How this Task works
Part of the problem seems to stem from the fact that some distributions
continue to include modules even if they fail some of their tests.
To get around that for this module, it will do a few dirty tricks.
If Scalar::Util is not available at all, it will issue a normal
dependency on the module. However, if Scalar::Util is relatively new (
it is >= 1.19 ) and the module does not have weaken, the install will
bail out altogether with a long error encouraging the user to seek
support from their vendor (this problem happens most often in
vendor-packaged Perl versions).
This distribution also contains tests to ensure that weaken is available
using more normal methods.
So if your module uses "weaken", you can just add the following to your
Module::Install-based Makefile.PL (or equivalent).
requires 'Task::Weaken' => 0;
Adam Kennedy <email@example.com>, <http://ali.as/>
Task, Scalar::Util, <http://ali.as/>
Copyright 2006 - 2009 Adam Kennedy.
This program is free software; you can redistribute it and/or modify it
under the same terms as Perl itself.
The full text of the license can be found in the LICENSE file included
with this module.