ecsd has asked for the wisdom of the Perl Monks concerning the following question: 

I get this (sort of thing):

cpan> install Bundle::CPAN

Recursive dependency detected:
    Bundle::CPAN
 => File::Spec
 => K/KW/KWILLIAMS/PathTools-3.03.tar.gz
 => Test
 => S/SB/SBURKE/Test-1.25.tar.gz
 => Test::Harness
 => P/PE/PETDANCE/Test-Harness-2.46.tar.gz
 => File::Spec.
Cannot continue.

"force install" does not fix it either.
How can I get past this? Tell it I don't care,
or break the chain of dependencies. Presumably there
aren't dependency loops for a real fact.

TIA

Replies are listed 'Best First'.
Re: CPAN, recursive dependency problem
by saintmike (Vicar) on Jan 28, 2005 at 01:16 UTC
    You could break the cycle by downloading individual tarballs, e.g: 
        cpan> get K/KW/KWILLIAMS/PathTools-3.03.tar.gz

    [download]
    hunt it down on disk (~/.cpan/sources/...), untar, build and install manually: 
        tar zxfv PathTools-3.03.tar.gz
    cd PathTools-3.03
    perl Makefile.PL
    make install

    [download]
[reply]
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      Where (or how) does CPAN's install figure that there is a dependency? I would like to be able to break stuff to lie to it,
      and I'd as soon break the "idea" that there is a dependency loop.

      Also, if this comes up with any frequency, I'd suggest enforcing some scheme to prevent such loops in the first place.
      I haven't seen any reference to this issue in any other FAQs (CPAN, Perl) but it bites often enough.

      Thanks for the information.
      -ecsd

[reply]
      It's worth pointing out that CPAN will also not allow a "get"
      of a module in a dependency chain, so that has to be done manually also.
[reply]
        It's worth pointing out that CPAN will also not allow a "get" of a module in a dependency chain ...

        Not true.

        Here's a quick way to verify dependencies (even circular ones): There's two modules on CPAN with the sole purpose of defining a circular dependency between each other: Acme::Prereq::A and Acme::Prereq::B.

        Acme::Prereq::A depends on Acme::Prereq::B and vice versa, see Acme::Prereq::A's Makefile.PL: 

            'PREREQ_PM'    => {
                         'Acme::Prereq::B' => 0,
                      }, # e.g., Module::Name => 1.1

        [download]

        Try it out, it works fine: 

            perl -MCPAN -eshell
    cpan> get Acme::Prereq::B

        [download]

        The CPAN shell's get command will fetch the requested module's tarball without checking dependencies.

        However, if you've run into a recursive dependency within a CPAN session, CPAN.pm will keep complaining, even if you switch to get. Restart the CPAN shell to get back to normal.

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Re: CPAN, recursive dependency problem
by Mr. Muskrat (Canon) on Jan 28, 2005 at 02:24 UTC

    Have you tried this?

    cpan> install File::Spec
[reply]
[d/l]

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