RPM Weak Dependencies and the install media compose process

[Neal Gompa]

On Fri, Jul 10, 2015 at 8:05 AM, Stephen Gallagher <sgallagh at redhat.com>
wrote:

>
> From my perspective, there are three ways that we could choose to go:
>
> 1) Follow the default DNF behavior: Requires: and Recommends: packages
> are included on the install media (and therefore also installed
> together onto the target system)
>
>
​I think this option makes the most sense, as it captures the current
behavior of DNF into the composition process. I honestly do not believe it
would make sense to allow the default behavior to differ from DNF,
especially as the vast majority of composes now are live images, making it
basically impossible to customize pre-install.​



> 2) Include *all* dependencies - Requires, Recommends and Suggests - on
> the install media. The installer would still follow DNF defaults, so
> the target system would get only the Requires and Recommends packages
> unless the Suggests: packages are explicitly selected (which will also
> require the creation of additional comps.xml changes to include the
> Suggests packages)
>
>
​While I appreciate the idea for completeness, I do not think this would go
over well as we update our packages to actually utilize weak dependencies
efficiently. However, I would be in favor of a kickstart parameter that
could switch on and off the inclusion of recommended and suggested packages
in a compose.

For example, in the %packages section, "--no_recommended_packages" and
"--add_suggested_packages" switches could be handy to alter the default
behavior to whatever a composer would want.



> 3) Include only Requires: dependencies by default and require spin
> -kickstarts owners to explicitly add any Recommends or Suggests
> packages that they also want to include. Packages added explicitly will
> be installed as described in 2) (requiring additional comps.xml changes
> to include Suggests stuff)
>
>
This is absolutely foolhardy, as we are fully deviating from ​how DNF
behaves and enshrining the hacks with comps that we simply do not need
anymore.
​


>
> Note that at the moment, DNF itself does not have a configuration
> option to tweak the default install behavior, so 'dnf install'
> effectively treats Recommends the same way as Requires (but 'dnf
> remove' will treat them differently, of course). I discussed this with
> the DNF developers this morning and they hope to have a configuration
> option and/or command-line argument available to change this behavior
> before Beta Freeze, so we should still be able to ship F23 with any of
> the above options.
>
>
​Excellent!​



> I think the best time to make these decisions is now, well in advance
> of the Alpha Freeze so we have time to make adjustments as needed.
> Thank you for reading to the end, I know the above has been a wall-o'
> -text.
>

​I completely agree, as the earlier we can decide on these things, the
better we'll all be. Thank you for bringing it up!



-- 
真実はいつも一つ！/ Always, there's only one truth!
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