Re: New package dependency field format
On Tue, 2 Sep 2003, Jason Gunthorpe wrote:
> Well, APT can't support this without huge amounts of effort. There are
> many places where it relies on being able to quicky look at a single
> dependency element to see if it is making progress. There are a whole
> bunch of optimizations that rely on this, and the 3sat approximation is
> based on this as well.
>
> Further, the dependency chains use the most memory out of everything, and
> they have been seriously space optimized. Adding all sorts of additional
> dynamic information is going to have a nasty overhead both for space and
> execution time. The dependency calculations are a major performance
> consideration in APT.
Well, {} is rather needed.
Brainstorming: There could be a bootup script that builds a cache of some
sort, that contains the list of runtime features that are available. This
could be based on the kernel and cpu. apt and dpkg could then read this
cache.
> > An astute observer will note that, strictly speaking, arch predicates
> > are superflous. One could just generate a unique dependency line for
> > the target arch when the deb is generated.
>
> So why should the baggage be carried into APT/DPKG?
I said it, so that someone might try to convince me that it's not needed. It
doesn't take much. I'll remove [] predicate.
However, the {} is needed. () may not be needed(it could be optimized
out). ! is probably needed.
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