Re: DEPENDS semantics (was: removing useless dependencies)

[David Brownlee <abs%absd.org@localhost>]

On 12 July 2015 11:18:41 BST, "Edgar Fuß" <ef%math.uni-bonn.de@localhost> wrote:
>DH> ...which is a bug.
>Well, one could argue it's not a bug because it doesn't violate the
>spec.
>Because there's no explicit spec, I guess.
>Of course, it's surprising behaviour and should be prominently
>documented.
>
>JS> Please stop asserting that random things are bugs without
>understanding
>JS> both the big picture and the details, thanks.
>
>DH> How does it make sense to compare version numbers of unrelated
>DH> packages?
>
>I'm afraid that, in the binary case, where you have no more information
>
>than "foo>=47.11 of bar>=0.8.15", it's the most un-unsensial
>tie-breaker 
>to choose. It's the only thing, that, at least in some cases like 
>"libfoo1>=1.11 or libfoo2>=2.22" may make sense.
>Any suggestion for a better way of tie-breaking? It would make sense to
>
>think of a way of expressing the tie-breaking rule inside the DEPENDS
>line, 
>but you would need a syntax expressing all common rules first.

If the possible dependencies are specified as an ordered list, then a reasonable expectation would be that the first one which is present is used. 

So {foo>=5.00, bar>=8.00} if there is a foo>=5 present then bar would never be even checked