On Mon, Feb 18, 2019 at 9:21 PM Ben Cotton <bcotton(a)redhat.com> wrote:
https://fedoraproject.org/wiki/Changes/BuildRequires_Generators
= BuildRequires Generators =
== Summary ==
Add possibility to generate build-time dependencies within RPM spec
file and teach RPM and mock how to handle this.
== Owner ==
* Name: [[User:ignatenkobrain|Igor Gnatenko]], [[User:ffesti|Florian
Festi]], [[User:msuchy|Miroslav SuchĂ˝]]
* Email: ignatenkobrain(a)fedoraproject.org, ffesti(a)redhat.com, miroslav(a)suchy.cz
== Detailed Description ==
For many languages (Rust, Golang, Node.Js, Ruby, Python),
BuildRequires can be automatically generated. All it takes, run some
special tool which will output dependencies in RPM format.
Q: How will it work under the hood?
A: When you build RPM, something like this will happen under the hood…
# rpm would perform %prep (which is supposed to abort if some
dependencies missing and print them)
# mock would install those dependencies and resume build
As of today, running %configure or %cmake is part of the %build step,
not the %prep step according to the guidelines.
Would it mean that we should move this kind of commands in the %prep
step? I think that's technically where they belong. However, focusing
on language stacks won't help for polyglot projects (for example when
using gcc in a Rust project).
Q: Will src.rpm contain all generated dependencies?
A: This is not known yet, we'll update page once it is known.
Q: Does this mean that package builds won't be reproducible anymore?
A: No, as long as you have same buildroot and tool which is generating
BuildRequires is doing so in reproducible manner, it should not affect
reproducibility.
== Benefit to Fedora ==
Packagers won't have to pre-generate BuildRequires in the spec file
which means it will be always updated (and correct) :
* Packagers can focus of making their packages better instead of
spending all their packaging time copying BuildRequires from
documentation and third party tools.
* BuildRequires are dropped as soon as they're no longer necessary
* Packages can be easily bumped without requiring a manual BuildRequires refresh
* BuildRequires and Requires generation can use similar utilities,
making sure that the deps packages declare can also be used for
second-level building. Packages no longer need to declare the deps of
their second and n-th dependencies because someone forgot to declare
them in the correct package.
== Scope ==
* Proposal owners: Implement support for a feature in RPM and mock (if
implemented properly, Koji should just work). Make use of it in Rust
ecosystem.
* Other developers: Maintainers of language stacks are advised to use
this feature.
* Release engineering: [
https://pagure.io/releng/issue/8129 #8129]
* Policies and guidelines: Packaging Guidelines need to be updated
with instructions how to use this feature.
* Trademark approval: N/A (not needed for this Change)
== Upgrade/compatibility impact ==
Packagers and users who use repoquery might be affected (src.rpm might
not contain generated dependencies).
== How To Test ==
TBD.
== User Experience ==
Users won't notice differences.
As a mock and RPM user on Fedora, outside of my Fedora endeavors, I
beg to differ ;-)
> == Dependencies ==
> Required feature needs to be implemented in RPM and mock.
>
> == Contingency Plan ==
> * Contingency mechanism: (What to do? Who will do it?) Proposal
> Owners might still ship feature disabled for Fedora buildsystem but
> have it available for end-users, and move full completion to the next
> release.
> * Contingency deadline: Beta Freeze
> * Blocks release? No.
> * Blocks product? No.
>
> == Documentation ==
> TBD.
>
> == Release Notes ==
> TBD.
>
> --
> Ben Cotton
> Fedora Program Manager
> TZ=America/Indiana/Indianapolis
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