Hello, On Fri 07 Jun 2019 at 10:50AM +01, Dominic Hargreaves wrote:
> diff --git a/policy/ch-relationships.rst b/policy/ch-relationships.rst > index 1d790e8..3b68420 100644 > --- a/policy/ch-relationships.rst > +++ b/policy/ch-relationships.rst > @@ -17,15 +17,16 @@ package names, separated by vertical bar (pipe) symbols > ``|``. In such a > case, that part of the dependency can be satisfied by any one of the > alternative packages. [#]_ > > -All of the fields except for ``Provides`` may restrict their > -applicability to particular versions of each named package. This is done > -in parentheses after each individual package name; the parentheses > -should contain a relation from the list below followed by a version > -number, in the format described in :ref:`s-f-Version`. > +All of the fields may restrict their applicability to particular versions > +of each named package. This is done in parentheses after each individual > +package name; the parentheses should contain a relation from the list > +below followed by a version number, in the format described in > +:ref:`s-f-Version`. > > The relations allowed are ``<<``, ``<=``, ``=``, ``>=`` and ``>>`` for > strictly earlier, earlier or equal, exactly equal, later or equal and > -strictly later, respectively. [#]_ > +strictly later, respectively. The exception is the Provides field, for > +which only ``=`` is allowed. [#]_ > > Whitespace may appear at any point in the version specification subject > to the rules in :ref:`s-controlsyntax`, and must appear > @@ -446,17 +447,43 @@ they can say: > and the ``bar-plus`` package will now also satisfy the dependency for > the ``foo`` package. > > -If a relationship field has a version number attached, only real > -packages will be considered to see whether the relationship is satisfied > -(or the prohibition violated, for a conflict or breakage). In other > -words, if a version number is specified, this is a request to ignore all > -``Provides`` for that package name and consider only real packages. The > -package manager will assume that a package providing that virtual > -package is not of the "right" version. A ``Provides`` field may not > -contain version numbers, and the version number of the concrete package > -which provides a particular virtual package will not be considered when > -considering a dependency on or conflict with the virtual package name. > -[#]_ > +A ``Provides`` field may contain version numbers, and such a version number > +will be considered when considering a dependency on or conflict with the > +virtual package name. [#]_ For example, given the following packages: > + > +:: > + > + Package: foo > + Depends: bar (>= 1.0) > + > + Package: bar > + Version: 0.9 > + > + Package: bar-plus > + Provides: bar (= 1.0) > + > +the ``bar-plus`` package will again satisfy the dependency for > +the ``foo`` package with the virtual package name. [#]_ If the ``Provides`` > +field does not specify a version number, it will not satisfy versioned > +dependencies or violate versioned ``Conflicts`` or ``Breaks``. For example, > +given the following packages: > + > +:: > + > + Package: foo > + Depends: bar (>= 1.0) > + > + Package: bar > + Version: 0.9 > + > + Package: bar-plus > + Provides: bar (= 1.0) > + > + Package: bar-clone > + Provides: bar > + > +the ``bar-plus`` package will satisfy the dependency for the ``foo`` > +package, but the ``bar-clone`` package will not. > > To specify which of a set of real packages should be the default to > satisfy a particular dependency on a virtual package, list the real > @@ -670,10 +697,8 @@ dependencies. > together and then configured in their dependency order. > > .. [#] > - It is possible that a future release of ``dpkg`` may add the ability > - to specify a version number for each virtual package it provides. > - This feature is not yet present, however, and is expected to be used > - only infrequently. > + This functionality was introduced in dpkg 1.17.11 and newer and > + full support has been provided in the Debian archive since 2018. > > .. [#] > To see why ``Breaks`` is normally needed in addition to ``Replaces``, Seconded. Thank you again. I've made some editorial changes (and fixed the introduction of a duplicate footnote reference) on branch bug761219-spwhitton of policy.git, but these do not need seconding. -- Sean Whitton
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