Re: [Module-build-general] A better passthrough Makefile.PL

[Ken W. <ke...@ma...>]

On Thursday, October 31, 2002, at 09:33  PM, Ken Williams wrote:
> Actually, I just had an idea - would the following small change work 
> (note the 'touch' line, "open $0")?
>
>   unless (eval "use Module::Build::Compat 0.02; 1" ) {
>     # Workaround with old CPAN.pm and CPANPLUS.pm
>     require ExtUtils::MakeMaker;
>     ExtUtils::MakeMaker::WriteMakefile(
>       PREREQ_PM => { 'Module::Build::Compat' => 0.02 }
>     );
>     warn "Warning: prerequisite Module::Build::Compat is not found.\n";
>     sleep 2;  # Wait a couple seconds after writing Makefile
>     open my($fh), ">> $0"  # Change modification date
>       or warn "You may have to run 'perl Makefile.PL' again.";
>     exit(0);
>   }
>   Module::Build::Compat->run_build_pl(args => \@ARGV);
>   Module::Build::Compat->write_makefile();
>
> The idea is that it changes the modification time for Makefile.PL to be 
> after the Makefile's, so that Makefile.PL gets re-run.

I got this working, but only sort of.  I had to change the open() stuff 
to utime() (duh) to get an effective touch.  But the problem is that 
even though the Makefile is rebuilt, CPAN.pm doesn't notice.  See below.


> This is kind of tough to test out - Dave, how did you test this before?

I figured out a really kludgey way to test it.

To get CPAN to build from local tarballs, I did this:

  1) Disconnect from the network so CPAN can't reload its metafiles.
  2) Replace the Makefile.PL for Params::Validate with a pass-through 
Makefile.PL like the one above, and create a Build.PL for it.
  3) Make a tarball of Params::Validate and put it in 
~/.cpan/sources/authors/id/D/DR/DROLSKY/.
  4) Uninstall Module::Build and Module::Build::Compat from my system.
  5) Make a tarball of Module::Build and put it in 
~/.cpan/sources/authors/id/K/KW/KWILLIAMS/.
  6) Delete the checksums for Module::Build and Params::Validate from the 
CHECKSUMS files in ~/.cpan/sources/authors/id/... since they're no 
longer valid.

Then in the cpan shell I did 'install Params::Validate' to see what 
would happen.  CPAN successfully notices that Module::Build is a 
prerequisite and installs it.  Then when it goes back to install 
Params::Validate, 'make' notices that the Makefile is out of date and 
rebuilds it, returning an error status.  But then for some reason CPAN 
extracts the tarball *again*, and rebuilds the blib/ or something, and 
everything goes to hell (where it can stay, as far as I'm concerned).

This means that in order to install Params::Validate, I had to do 
'install Params::Validate', 'clean Params::Validate', 'install 
Params::Validate'.  Ish.

I think it also didn't get the prerequisites right - CPAN probably only 
registered a prereq of Module::Build, and not Attribute::Handlers.

So I think we'll indeed have to invoke CPAN->install if we want it to be 
all in one step.  I'll try that next.

  -Ken