Not sure I understand what you're saying here. What exactly Task has to do with this problem? I'm not trying to bundle the whole suite of modules in one distribution, I'm trying to find an easy way to prevent the modules dependent on Foo from upgrading it. Say, I publish Foo::Bar that depends on Foo 2.0; that will make cpanm install Foo 2.0 automagically whenever Foo::Bar itself is updated - just because cpanm will fetch the greatest version of Foo::Bar available without regard to the major versions.

If you're suggesting to use Task::Foo2x as a marker of sorts, then it can be done with an empty module instead. I think.

Also I'm not sure that the approach you're advocating will bode well with the CPAN testers. I really appreciate the reports and don't want to lose them; dying in Makefile.PL would most probably break the toolchain and require manual intervention. Which I really doubt anybody would do.

Regards,
Alex.