On 06/10/2021 17:23, Jon Turney wrote:
On 06/10/2021 13:01, Ken Brown via Cygwin-apps wrote:
This seems to work, with one caveat. Suppose package P requires
feature f, and packages Q, R, S,... provide f. If the user selects P
and one or more of Q, R, S,..., setup is happy. But if the user
simply selects P, then setup/libsolv will choose among Q, R, S,... the
one whose name is alphabetically first. In the emacs case, this would
be emacs-lucid, which is a stupid default. The default ought to be
emacs-nox. So I can make it work if I call that package emacs-basic
instead of emacs-nox.
Yeah, I think what's wanted here is for the solver to output a problem
with the choices, rather than picking one. I'm not sure how to get it
to do that.
(Ofc, then we need some UI for picking problem solutions, rather than
just always using the default)
Thinking about this some more, that's probably not how it wants to work,
since just installing emacs-common would then require user interaction
to solve the problem, rather than just installing emacs-nox as well...
(and I'm not sure how we'd encode "emacs-basic" should be the default
provider of "emacs-bin" as the input into the solver; presumably there'd
by some scheme with weights attached to provide names to set the order
rather than alphabetic)
So all that's left is to fix that.
This is discussed somewhat in [1], and it seems that having emacs-common
suggest: or weak-dep: on emacs-nox would cause that to be the preferred
provide:r by the solver (in the absence of other provide:ing packages
being selected or installed)
So I guess we'd need to add something like that to setup.ini and feed
that data into the solver as well.
[1] https://github.com/openSUSE/libsolv/issues/66
