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Re: About the Breaks: field.

>>"Guy" == Guy Maor <maor@ece.utexas.edu> writes:

Guy> Guy Maor <maor@ece.utexas.edu> writes:
>> Conflicts is like a reverse Depends.  It affects package
>> configuration.
>> Breaks is like a reverse Pre-Depends.  It affects package
>> unpacking.

Guy> Some investigation reveals that I was wrong.  A package which
Guy> conflicts with a package whose state is unpacked or higher won't
Guy> even unpack.

	Under the current system ;-). 

Guy> One major problem with Conflicts is that dpkg doesn't detect if
Guy> the Conflicts can be resolved by reordering package unpacking.
Guy> In fact, dpkg doesn't reorder package unpacking, only package
Guy> configuration.

	Deity will hopefully be more aware.

Guy> Santiago's proposal said that Breaks would cause a reorder of
Guy> package unpacking.  I see no reason why it cannot be added for
Guy> Conflicts. Probably that's what Ian meant.

	I still like the symmetry of depends and predepends with
 conflicts and breaks. The stricter relationships require completion
 of tasks before unpacking dependant packages. So a mere conflicts
 relationship may not guarantee resolution before unpacking anymore;
 we have breaks for that.

	I think this improves efficiency of the massive upgrade

Guy> So the all too common case of: fooA_1 and fooB_1 are
Guy> installed. We'd like to upgrade to fooA_2 and fooB_2, but we MUST
Guy> upgrade fooA first. can't be done automatically!!

	I'd like to throw this against my simulator. This would be
 something that should be made to work.

Guy> Ideally, two things have to happen in dpkg:

Guy> 1. Unpacking is reordered according to Conflicts lines.

	Amongst other things, yes, I am thinking about this. Unpacking
 order also depends on other relationships as well ;-).

Guy> 2. New unpack-configure cycles are introduced to support
Guy> Pre-Depends. The current way of doing pre-dependencies is rather
Guy> crude (with --predep-package), and neither version of dpkg-ftp
Guy> even supports it!

	This is also going to be done (looking at pkg-order as a
 working prototype)

Guy> Unfortunately there's a nasty bout of Dpkg Programmer's Disease
Guy> going around.  Anyone that looks at the source long enough to
Guy> have a vague idea of what's going on instantly drops off the
Guy> planet.  I fear the worst...  ;-)

	I must increase my insurance policies ... ;-)

 "In the carriages of the past you can't go anywhere."  Maxim Gorkey
Manoj Srivastava               <url:mailto:srivasta@acm.org>
Mobile, Alabama USA            <url:http://www.datasync.com/%7Esrivasta/>

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