On Wed, Jul 21, 2010 at 01:37:28PM -0700, Russ Allbery wrote: > >> <p> > >> When one binary package declares a conflict with another > >> using a <tt>Conflicts</tt> field, <prgn>dpkg</prgn> will > >> - refuse to allow them to be installed on the system at the > >> + refuse to allow them to be unpacked on the system at the > >> same time. This is a stronger restriction than <tt>Breaks</tt>, > >> which just prevents both packages from being configured at the > >> same time. Conflicting packages cannot be unpacked on the > > Whoops. > > This is a stronger restriction than <tt>Breaks</tt>, > > which only prevents the broken package from being configured at > > the same time as the breaking package is unpacked. > I believe what I wrote is more correct than what you wrote. What do you > think is wrong about it which prompts the "whoops"? Breaks allows both > packages to be unpacked at the same time, but only one of the two packages > can be configured at the same time. Configuring one package will result > in deconfiguring the other. (At least. I think under normal > circumstances the broken package is then removed, although I'm not sure > since Policy never says that. All Policy says will happen is that it will > be deconfigured.) I don't think it's a "whoops", but it is true that Breaks is asymmetric and it's specifically the /broken/ package that is deconfigured when the /breaking/ package is unpacked, and I think Policy should be clear about this. (Yes, the fact that the package manager normally proceeds to remove the broken package is an apt policy, not Policy.) So I think it's better to say: This is a stronger restriction than <tt>Breaks</tt>, which just prevents the package listed in the Breaks field from being configured while the package with the Breaks field is present on the system. Avoids referring to packages listed in Breaks as 'broken', which it seems we're trying to do even though we use the common English verbs throughout Policy for the other relationship fields; and avoids the ambiguous "is unpacked" where what we really mean is the much more bulky "is in an unpacked state". The whole thing comes out pretty awkward for all that, but I have no ideas on further improving it. -- Steve Langasek Give me a lever long enough and a Free OS Debian Developer to set it on, and I can move the world. Ubuntu Developer http://www.debian.org/ slangasek@ubuntu.com vorlon@debian.org
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