Converted Module::Build to use Meta 2.0 inside

[Leont]

This converts Module::Build to use Meta 2.0 inside, closing #18. This fixes a number of issues such as #14. This has a number of backwards compatibility issues, in particular:

• get_meta now returns meta 2.0, so anything assuming 1.x may break
• meta_merge and meta_add are limited to items that can easily be upgraded to meta 2.0, unless they're declared to be 2.0. This includes prereqs (which is a stupid thing to meta add/merge anyway).

[Leont]

I just uploaded 0.40_09, which includes a rebased/squashed version of this. Testing is most welcome, this is a major change and the next stable release will be a version bump to 0.4200 to indicate this.

[kenahoo]

Fails for me on OS X 10.7.5, perl 5.18.0:

[Loblolly:/tmp/Module-Build-0.40_09] % perl Build.PL 
Could not get valid metadata. Error is: Invalid metadata structure. Errors: License 'Perl_5' is invalid (license -> Perl_5) [Validation: 2]
 at lib/Module/Build/Base.pm line 4544.

Can't call method "effective_prereqs" on an undefined value at lib/Module/Build/Base.pm line 1917.

[miyagawa]

Looks like it's missing Software::License.

[Leont]

Could not get valid metadata. Error is: Invalid metadata structure. Errors: License 'Perl_5' is invalid (license -> Perl_5) [Validation: 2] at lib/Module/Build/Base.pm line 4544.

Hmm. It seems the licenses for the conversion hash should be lowercased, 'Perl_5' isn't valid, but 'perl_5' is. Titlecased is for Software::License submodules.

Can't call method "effective_prereqs" on an undefined value at lib/Module/Build/Base.pm line 1917.

That seems to be a domino effect. The code assumed it can always create a mymeta object if there's a meta object.

Just pushed out 0.40_10, which should fix both issues.

[Leont]

Closed, as this this has been fixed in the 0.420X series of releases.