Now, two things have happened since this. The first, I mentioned in my post on the latest release of MooseX::AttributeCloner, about the fact that 'passthrough' is being deprecated as an option for dist producing a Makefile.PL.
I won't go into that one now, but the second is potentially more disastrous.
Before I go any further, I would like to make it clear that this is not an attempt to slag off the people who write/maintain Module::Build. The tool is extremely useful, and I got a very helpful response from David Golden about my RT ticket. I would like to say Thankyou for producing the tool. The below is possibly more our abuse of it than their failings with it.
We use Test::Perl::Critic to monitor our coding standards. (OK, I accept that it is a set of guidelines, and is in no way compulsory, but it is a start.) Perlcritic wants $VERSION to be a constant, and to do this within the code, we use (as for all constants)
Readonly::Scalar our $VERSION => do { my ($r) = q$LastChangedRevision: 8362 $ =~ /(\d+)/mxs; $r; };
(Again, yes, taking the version number from a version control system is supposedly 'not good', but it works for us, and others I know)
When I run perl Makefile.PL, I get the following:
(note, I use the passthrough or small Makefile.PL and perl Makefile.PL to run Build.PL)
Creating new 'MYMETA.yml' with configuration results
Error evaling version line 'BEGIN { q# Hide from _packages_inside()
#; package Module::Build::ModuleInfo::_version::p56;
use Module::Build::Version;
no strict;
local $VERSION;
$VERSION=undef;
$vsub = sub {
Readonly::Scalar our $VERSION => do { my ($r) = q$LastChangedRevision: 8362 $ =~ /(\d+)/mxs; $r; };;
$VERSION
};
}' in /this/package/lib/module.pm: syntax error at (eval 92) line 9, near "Readonly::Scalar our "
BEGIN not safe after errors--compilation aborted at (eval 92) line 11,
failed to build version sub for /this/package/lib/module.pm at /Users/ajb/dev/perl/5.10.1/lib/5.10.1/Module/Build/ModuleInfo.pm line 332,
WARNING: Possible missing or corrupt 'MANIFEST' file.
Nothing to enter for 'provides' field in metafile.
Creating new 'Build' script for 'my_project' version '8391.'
OK, in this case, it's a warning, but the Build file is created, and I can do what I need to.
However, updating the Build.PL 'requires' to include some other package libs, the problem becomes more serious.
Error evaling version line 'BEGIN { q# Hide from _packages_inside()
#; package Module::Build::ModuleInfo::_version::p5;
use Module::Build::Version;
no strict;
local $VERSION;
$VERSION=undef;
$vsub = sub {
Readonly::Scalar our $VERSION => do { my ($r) = q$LastChangedRevision: 8212 $ =~ /(\d+)/mxs; $r; };;
$VERSION
};
}' in /another/package/lib/module.pm: syntax error at (eval 28) line 9, near "Readonly::Scalar our "
BEGIN not safe after errors--compilation aborted at (eval 28) line 11,
failed to build version sub for /another/package/lib/module.pm at /Users/ajb/dev/perl/5.10.1/lib/5.10.1/Module/Build/ModuleInfo.pm line 332,
Couldn't run Build.PL: No such file or directory at /Users/ajb/dev/perl/5.10.1/lib/5.10.1/Module/Build/Compat.pm line 335.
Here, because it can't identify the version of the 'external' module, it has croaked out.
I submitted a bug report, and David Golden (Big thanks to him for responding) suggested that before the line could perhaps be made
use Readonly; Readonly::Scalar our $VERSION => do { my ($r) = q$LastChangedRevision: 8212 $ =~ /(\d+)/mxs; $r; };
since the problem is in the eval block.
This is fine to do for internal modules, but a problem for anything we install centrally from CPAN (maintenance of code, root access, etc).
I tried using Module::Install as an alternative. This carps errors in both cases, but in both cases doesn't cause the Makefile not to be created.
This post therefore comes down to 2 things.
1) Information to anyone who really cares or reads this blog.
2) Are we the only people who use Readonly::Scalar to declare 'our $VERSION'? (in which case, MooseX::AttributeCloner is possibly the only module on CPAN which does this)
Thoughts and comments welcome, although I would appreciate people not calling us Idiots (or stronger) for using Readonly::Scalar to 'constant'ify the variable (or at least not without good reason). We have looked at use version;, but it doesn't seem to be right with using a version control value.
Again, thanks to the authors/maintainers of Module::Build and Module::Install for these wonderful tools.
