---
name: "CPAN::Meta::Prereqs"
section: "3p"
platform: "openbsd"
package: "man"
version: "8.0-current-20261101"
release: "OpenBSD 8.0-current (2026-11-01)"
platforms: ["openbsd"]
url: "https://new.carta.tech/CPAN::Meta::Prereqs"
---

# CPAN::Meta::Prereqs(3p)

a set of distribution prerequisites by phase and type

## NAME

CPAN::Meta::Prereqs - a set of distribution prerequisites by phase and type

## VERSION

version 2.150010

## DESCRIPTION

A CPAN::Meta::Prereqs object represents the prerequisites for a CPAN distribution or one of its optional features.  Each set of prereqs is organized by phase and type, as described in CPAN::Meta::Prereqs.

## METHODS

### new

```
  my $prereq = CPAN::Meta::Prereqs->new( \%prereq_spec );
```

This method returns a new set of Prereqs.  The input should look like the contents of the `"prereqs"` field described in CPAN::Meta::Spec, meaning something more or less like this:

```
  my $prereq = CPAN::Meta::Prereqs->new({
    runtime => {
      requires => {
        'Some::Module' => '1.234',
        ...,
      },
      ...,
    },
    ...,
  });
```

You can also construct an empty set of prereqs with:

```
  my $prereqs = CPAN::Meta::Prereqs->new;
```

This empty set of prereqs is useful for accumulating new prereqs before finally dumping the whole set into a structure or string.

### requirements\_for

```
  my $requirements = $prereqs->requirements_for( $phase, $type );
```

This method returns a CPAN::Meta::Requirements object for the given phase/type combination.  If no prerequisites are registered for that combination, a new CPAN::Meta::Requirements object will be returned, and it may be added to as needed.

If `$phase` or `$type` are undefined or otherwise invalid, an exception will be raised.

### phases

```
  my @phases = $prereqs->phases;
```

This method returns the list of all phases currently populated in the prereqs object, suitable for iterating.

### types\_in

```
  my @runtime_types = $prereqs->types_in('runtime');
```

This method returns the list of all types currently populated in the prereqs object for the provided phase, suitable for iterating.

### with\_merged\_prereqs

```
  my $new_prereqs = $prereqs->with_merged_prereqs( $other_prereqs );
  my $new_prereqs = $prereqs->with_merged_prereqs( \@other_prereqs );
```

This method returns a new CPAN::Meta::Prereqs objects in which all the other prerequisites given are merged into the current set.  This is primarily provided for combining a distribution's core prereqs with the prereqs of one of its optional features.

The new prereqs object has no ties to the originals, and altering it further will not alter them.

### merged\_requirements

```
    my $new_reqs = $prereqs->merged_requirements( \@phases, \@types );
    my $new_reqs = $prereqs->merged_requirements( \@phases );
    my $new_reqs = $prereqs->merged_requirements();
```

This method joins together all requirements across a number of phases and types into a new CPAN::Meta::Requirements object.  If arguments are omitted, it defaults to "runtime", "build" and "test" for phases and "requires" and "recommends" for types.

### as\_string\_hash

This method returns a hashref containing structures suitable for dumping into a distmeta data structure.  It is made up of hashes and strings, only; there will be no Prereqs, CPAN::Meta::Requirements, or `"version"` objects inside it.

### is\_finalized

This method returns true if the set of prereqs has been marked "finalized," and cannot be altered.

### finalize

Calling `"finalize"` on a Prereqs object will close it for further modification. Attempting to make any changes that would actually alter the prereqs will result in an exception being thrown.

### clone

```
  my $cloned_prereqs = $prereqs->clone;
```

This method returns a Prereqs object that is identical to the original object, but can be altered without affecting the original object.  Finalization does not survive cloning, meaning that you may clone a finalized set of prereqs and then modify the clone.

## BUGS

Please report any bugs or feature using the CPAN Request Tracker. Bugs can be submitted through the web interface at \<http://rt.cpan.org/Dist/Display.html?Queue=CPAN-Meta\>

When submitting a bug or request, please include a test-file or a patch to an existing test-file that illustrates the bug or desired feature.

## AUTHORS

- •

  David Golden \<dagolden@cpan.org\>

- •

  Ricardo Signes \<rjbs@cpan.org\>

- •

  Adam Kennedy \<adamk@cpan.org\>

## COPYRIGHT AND LICENSE

This software is copyright (c) 2010 by David Golden, Ricardo Signes, Adam Kennedy and Contributors.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.