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Re: [RFC] calm, setup: per-version requires
- From: Jon Turney <jon dot turney at dronecode dot org dot uk>
- To: cygwin-apps at cygwin dot com
- Date: Tue, 5 Dec 2017 14:32:52 +0000
- Subject: Re: [RFC] calm, setup: per-version requires
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On 09/11/2017 18:18, Achim Gratz wrote:
Jon Turney writes:
On 05/11/2017 07:34, Achim Gratz wrote:
Yeah, I guess we could generate requires: line in each version section
now, and this might work with current setup. I don't think this did
anything useful prior to  being fixed.
Yes, and even though I think the parser would accept them they weren't
really expected anyway.
The libsolv branch implements per-version '[dD]epends:' headers as per
 (which may also contain a version relation)
I'd really prefer we'd come up with a solution that does not have us
repeat the common dependencies for each version present.
My current plan is to do the simplest thing:
- requires: remains the union of dependencies
- if the version has a depends: hint, use that for depends: (not
something cygport is currently capable of generating)
- otherwise, generate depends: from the requires: hint for the version
It's probably useful to bear in mind how various versions of setup will
behave if I was to turn on 'depends:' generation in calm. From staring
at the code (so subject to testing), I think it breaks down as follows:
prior to 2.880: Will ignore 'depends:', so 'requires:' needs to remain
the union of dependencies for the benefit of these versions of setup.
2.880 onwards: The curr: version will get the union of 'depends:' and
'requires:', other versions will get 'requires:'.
The prereq checker checks that the dependencies are satisfied (including
any version relation), but then installs the 'curr:' or 'test:' version
(depending on chooser preference) imagining that will satisfy it.
libsolv-based: 'depends:' supersedes 'requires:', installs the right
right thing (hopefully :))