Bug#623291: Clarify that dependency loops involving relations like Suggests are ok
On Mon, Apr 18, 2011 at 08:57:26PM -0500, Jonathan Nieder wrote:
> Package: debian-policy
> Version: 3.9.2.0
> Severity: minor
>
> > Wouldn't that create a circular dependency?
> > pcscd Depends: libpcsclite1
> > libpcsclite1 Suggests: pcscd
> >
> > I fixed a similar problem in #612972 a few weeks ago.
>
> It seems that policy uses the term dependency for all package
> relationships declared in debian/control. So unless one pays close
> attention to the context, it is possible to read
>
> Packages should therefore avoid circular dependencies where
> possible, particularly if they have <prgn>postinst</prgn>
> scripts.
>
> as meaning that a Depends relation in one direction with a Suggests
> relation in the other direction is a circular dependency and something
> to be avoided.
>
> I do not think that is the intention. Potential fixes:
>
> - Use the term "relationship" instead of "dependency" throughout. It
> is confusing to call conflicts and Breaks relations dependencies
> anyway (I guess a conflict with X is a dependency on not-X).
>
> - Be more explicit that "circular dependencies" means chains of
> Depends relations starting and ending at the same package. While at
> it, mention that chains of Depends and Pre-Depends relationships
> starting and ending at the same package are not allowed (in
> addition to the existing text which says "Pre-Depends does not
> permit circular dependencies to be broken").
Circular dependencies occurs in the context of the section you are excerpting.
Specifically:
`Depends':
This declares an absolute dependency. A package will not be
configured unless all of the packages listed in its `Depends'
field have been correctly configured
However the discussion of circular dependencies is not directly normative: it is mostly a
consequence of other normative part of policy.
Maybe we should move the 'circular dependencies' content in the Depends section to a new section
entitled "Circular Dependencies" that define the concept and document dpkg behaviour.
Cheers,
--
Bill. <ballombe@debian.org>
Imagine a large red swirl here.
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