[Module::Build] Module requirements (was: Module::Build and installing in non-standard locations)

[Randy W. S. <Ra...@Th...>]

Adam Kennedy wrote:
 >> There are a number of ways to do this. The most simple is:
 >>
 >> use strict;
 >> use warnings;
 >>
 >> use File::HomeDir;
 >> my $conf_dir = File::Spec->catdir( File::HomeDir->my_home, '.Foo' );
 >
 >
 > Not that I wish to be a pedant about this, but only so people keep it in
 > mind...
 >
 > This installer will crash with a non-useful error message if someone
 > tries to install of < 5.006, and has an implicit undeclared (still
 > unresolvable I believe) dependency on File::HomeDir.

How is this different from a Makefile.PL or any other perl script with a 
C<use> statement. If the C<use>d module can't be found, it says it can't 
be found. It doesn't crash.

Sure, the dependency should be listed in META.yml. And, there is a way 
to that so that CPAN.pm and other tools can see the dependency before 
running the Build.PL: You simply list it in C<requres> argument to the 
constructor. But this was just a simplified example to illustrate a 
different point...

 > (I'll shut up about the whole implicit undeclared unresolvable
 > dependency on Module::Build for a while, given it's now in the core and
 > I've had a good long chat about the issue with Tony.)

Again, how is this different from MakeMaker's Makefile.PL which, strange 
enough, requires MakeMaker to be present?

 > So if you use warnings in your Build.PL you should always do it as
 >
 > use 5.006;
 > use strict;
 > use warnings;

I agree, this is true of any script, not just Build.PL.

 > As for how to ensure File::HomeDir is installed before you actually know
 > what you dependencies are, well I dunno, but this problem is going to
 > keep coming back and haunting us till MB supports bundling of some kind.

Bundling is *a* solution to *some* problems *some* of the time. From 
what I understand there's a pretty good module out there that helps with 
that ;). But I'm not yet convinced that it should be the default method 
for every distribution. Authors should have a choice. For people who 
want to bundle Module::Build it's simple to do by hand, and it's been 
done by authors who decided that was best for their distribution.

Regards,
Randy.