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Dpkg::Deps(3perl)                 libdpkg-perl                Dpkg::Deps(3perl)

NAME
       Dpkg::Deps - parse and manipulate dependencies of Debian packages

DESCRIPTION
       The Dpkg::Deps module provides classes implementing various types of
       dependencies.

       The most important function is deps_parse(), it turns a dependency line
       in a set of Dpkg::Deps::{Simple,AND,OR,Union} objects depending on the
       case.

FUNCTIONS
       All the deps_* functions are exported by default.

       deps_eval_implication($rel_p, $v_p, $rel_q, $v_q)
           ($rel_p,  $v_p)  and  ($rel_q,  $v_q)  express  two  dependencies as
           (relation, version). The relation variable can  have  the  following
           values  that  are exported by Dpkg::Version: REL_EQ, REL_LT, REL_LE,
           REL_GT, REL_GT.

           This functions returns 1 if  the  "p"  dependency  implies  the  "q"
           dependency.  It  returns 0 if the "p" dependency implies that "q" is
           not satisfied. It returns undef when there's no implication.

           The $v_p and $v_q parameter should be Dpkg::Version objects.

       $dep = deps_concat(@dep_list)
           This function concatenates multiple dependency lines into  a  single
           line,  joining them with ", " if appropriate, and always returning a
           valid string.

       $dep = deps_parse($line, %opts)
           This function parses the dependency  line  and  returns  an  object,
           either a Dpkg::Deps::AND or a Dpkg::Deps::Union. Various options can
           alter the behavior of that function.

           use_arch (defaults to 1)
               Take  into  account  the  architecture  restriction  part of the
               dependencies.  Set to 0 to completely ignore that information.

           host_arch (defaults to the current architecture)
               Define   the   host   architecture.   By   default    it    uses
               Dpkg::Arch::get_host_arch() to identify the proper architecture.

           build_arch (defaults to the current architecture)
               Define    the   build   architecture.   By   default   it   uses
               Dpkg::Arch::get_build_arch()    to    identify    the     proper
               architecture.

           reduce_arch (defaults to 0)
               If set to 1, ignore dependencies that do not concern the current
               host  architecture.  This implicitly strips off the architecture
               restriction list so that the resulting dependencies are directly
               applicable to the current architecture.

           use_profiles (defaults to 1)
               Take  into  account  the  profile  restriction   part   of   the
               dependencies. Set to 0 to completely ignore that information.

           build_profiles (defaults to no profile)
               Define  the  active  build  profiles.  By  default no profile is
               defined.

           reduce_profiles (defaults to 0)
               If set to 1, ignore dependencies that do not concern the current
               build  profile.  This  implicitly   strips   off   the   profile
               restriction  formula  so  that  the  resulting  dependencies are
               directly applicable to the current profiles.

           reduce_restrictions (defaults to 0)
               If set to 1, ignore dependencies that do not concern the current
               set of restrictions. This implicitly strips off any architecture
               restriction list or restriction formula so  that  the  resulting
               dependencies are directly applicable to the current restriction.
               This  currently implies "reduce_arch" and "reduce_profiles", and
               overrides them if set.

           union (defaults to 0)
               If  set  to  1,  returns  a  Dpkg::Deps::Union  instead   of   a
               Dpkg::Deps::AND.   Use  this  when parsing non-dependency fields
               like Conflicts.

           virtual (defaults to 0)
               If set to 1, allow only virtual package version relations,  that
               is  none,  or  "=".   This  should  be set whenever working with
               Provides fields.

           build_dep (defaults to 0)
               If set to 1, allow  build-dep  only  arch  qualifiers,  that  is
               ":native".  This should be set whenever working with build-deps.

           tests_dep (defaults to 0)
               If set to 1, allow tests-specific package names in dependencies,
               that  is  "@" and "@builddeps@" (since dpkg 1.18.7). This should
               be  set   whenever   working   with   dependency   fields   from
               debian/tests/control.

               This   option  implicitly  (and  forcibly)  enables  "build_dep"
               because test dependencies are based on build dependencies (since
               dpkg 1.22.1).

       $bool = deps_iterate($deps, $callback_func)
           This function visits all elements of the dependency object,  calling
           the callback function for each element.

           The  callback function is expected to return true when everything is
           fine, or false if something went wrong, in which case the  iteration
           will stop.

           Return the same value as the callback function.

       deps_compare($a, $b)
           Implements  a  comparison  operator  between two dependency objects.
           This function is mainly used to implement the sort() method.

CLASSES - Dpkg::Deps::*
       There are several kind of dependencies. A Dpkg::Deps::Simple  dependency
       represents  a  single  dependency  statement  (it relates to one package
       only).  Dpkg::Deps::Multiple dependencies are built on top of this class
       and combine several dependencies in different  manners.  Dpkg::Deps::AND
       represents  the  logical "AND" between dependencies while Dpkg::Deps::OR
       represents the logical "OR". Dpkg::Deps::Multiple  objects  can  contain
       Dpkg::Deps::Simple object as well as other Dpkg::Deps::Multiple objects.

       In practice, the code is only meant to handle the realistic cases which,
       given Debian's dependencies structure, imply those restrictions: AND can
       contain Simple or OR objects, OR can only contain Simple objects.

       Dpkg::Deps::KnownFacts  is a special class that is used while evaluating
       dependencies and while trying to simplify them. It represents a  set  of
       installed  packages  along  with  the  virtual  packages that they might
       provide.

CHANGES
   Version 1.07 (dpkg 1.20.0)
       New option: Add virtual option to deps_parse().

   Version 1.06 (dpkg 1.18.7; module version bumped on dpkg 1.18.24)
       New option: Add tests_dep option to deps_parse().

   Version 1.05 (dpkg 1.17.14)
       New function: deps_iterate().

   Version 1.04 (dpkg 1.17.10)
       New  options:  Add  use_profiles,  build_profiles,  reduce_profiles  and
       reduce_restrictions to deps_parse().

   Version 1.03 (dpkg 1.17.0)
       New option: Add build_arch option to deps_parse().

   Version 1.02 (dpkg 1.17.0)
       New function: deps_concat()

   Version 1.01 (dpkg 1.16.1)
       <Used  to  document  changes  to  Dpkg::Deps::* modules before they were
       split.>

   Version 1.00 (dpkg 1.15.6)
       Mark the module as public.

1.22.21                            2025-06-30                 Dpkg::Deps(3perl)

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