Re: Extensions Dependency Checking

Aidan Van Dyk <aidan@highrise.ca> writes:
> On Mon, Apr 4, 2011 at 6:06 PM, Robert Haas <robertmhaas@gmail.com> wrote:
>> Oh, really? �How can you possibly get by without it? �Dependencies of
>> this type are all over the place.

> I think the general movement is toward *feature* dependancies.  So for
> intstance, an extension can specify what *feature* it requires, and
> difference "versions" of an extension can provide different
> "features".

Right.

> But checking http://developer.postgresql.org/pgdocs/postgres/extend-extensions.html,
> I don't see any "provides" mechanism.

Yes, some sort of manual Provides: (in addition to automatically
extracted Provides:) would likely be part of any serious solution.
We're not there yet, and we're not going to get there in time for 9.1.
But in any case, mechanisms that involve version ordering comparisons
seem to be on their way out for deciding whether package A is
compatible with package B.
        regards, tom lane