In a Perl distribution, what would be the recommended way to specify a "dependency" type that says: update these modules to at least these versions, if you have them installed?

I would do something like (untested):

In the Makefile.PL, list all dependencies along with their minimum required versions: 
...
my %min_version = (Some/Place/Foo.pm => 0.06, # need at least version 
+0.06 of Some::Place::Foo
                   Other/Spot/Bar.pm => 1.35, # need at least version 
+1.35 of Other::Spot::Bar
                   Baz.pm            => 2.72, # need at least version 
+2.72 of Baz
                   );  

my @prereqs;

for(keys(%min_version)) {
  eval {require $_};
  # Ignore modules that don't load.
  unless($@){
    my $m = $_;
    $m =~ s/\//::/g;
    $m =~ s/\.pm$//;
    my $v = $min_version{$_};
    push @prereqs($m, $v);
  }
}

my %h = @prereqs;
....

[download]
And then, in WriteMakefile() section of the Makefile.PL, I would specify: 
...
'PREREQ_PM' => \%h,
...

[download]
Cheers,
Rob

In reply to Re: Update these modules if installed? by syphilis
in thread Update dependants if installed (was: Update these modules if installed?) by perlancar

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