feat: allow specifying whether you want sdists or not

[baszalmstra]

This adds the option to specify whether you want to use sdists, prefer them or only use sdists.

[notatallshaw]

you want to use sdists, prefer them or only use sdists

Sorry, I've not quite got the hang of reading Rust PRs yet, but please make sure there's an option for "prefer not to use them",and IMO that should be the default option), if that in fact is not already the case here (perhaps that is what is meant implictly by "you want to use sdists").

[baszalmstra]

This PR adds the following options:

• Normal (the default): this means we consider any version that has wheels and/or sdists and we sort them based on version.
• PreferWheels: this means we still consider both sdists and wheels but only if no version could be found that has wheels we consider versions with an sdist.
• PreferSdists: this is the opposite of the above. We consider versions with both artifacts but select a version with a sdist over that with a wheel.
• OnlyWheels: dont take sdists into consideration at all, only wheels. No solution is found if there are no wheels.
• OnlySDists: dont take wheels into consideration at all, only sdists. No solution is found if there are no sdists.

Do you think that suffices?

[notatallshaw]

Options seem great, but the default comes with a lot of nuance and introduces backwards compatability issues if you need to change much later down the road.

I would personally suggest PreferWheels, a wheel is less likely to have issues than an sdist, and this option is only going to go wrong if a project goes from publishing wheels to only publishing sdists, which would be highly unusual.

There's bewen a discussion in Pip world about changing the default and the problem with backwards compatability for them: pypa/pip#9140 (sorry long discussion)

[tdejager]

Hi @notatallshaw thanks for your input! I don't mind preferring wheels if you (as the expert :)) says it's a better idea!

[tdejager]

wheels to only publishing sdists, which would be highly unusual.

Like here 😢 : https://pypi.org/simple/pysdl2/

[baszalmstra]

@tdejager I added thorough docs to the SDistResolution struct. WDYT?

[baszalmstra]

@pradyunsg what do you think of these options? What do you think should be the default here?

[notatallshaw]

Like here 😢 : https://pypi.org/simple/pysdl2/

Oh wow, 🙁, well Normal is definetly universally safe for rip. But the common example of user pain is when there's a new release and wheels are not released along side sdists immediatly.

Bas has fixed the wording

[pradyunsg]

what do you think of these options?

They're reasonable, although given that you have low backwards compatibility costs; I suggest using more granular control (eg: enabling people to say "get me X, Y&Z from an sdist with everything else being wheels".

What do you think should be the default here?

Matching pip's default semantic of "use a wheel if available for a version, otherwise sdist for that version" is likely going to be the most compatible with existing user workflows.