pytest_make_parametrize_id hook

[palaviv]

This PR is implementing @nicoddemus suggestion in issue #930.

[nicoddemus]

I thought it would be useful to also receive the config object. Some plugin might add some custom options that might affect this.

[nicoddemus]

Thanks @palaviv for taking the time to work on this!

[palaviv]

I added the config object to the hook.

[nicoddemus]

If nobody else wants to chime in, I will merge this tomorrow. 😁

[RonnyPfannschmidt]

since this is a new hook, can we mark it as "experimental" ?
i don't suspect much change at first glance, but we that's also why its a good chance to experiment with such a concept/tool

[nicoddemus]

since this is a new hook, can we mark it as "experimental" ?

I'm not totally against that, but could you clarify exactly what you want "experimental" to mean here in this context? For example, we might remove arguments or the hook itself in the future?

I ask because hooks are forward compatible, and if in the future we realize we need some other argument, we can just add that and not break anything.

I think we should define exactly what we mean by "experimental", like what might happen in the future with that feature, and when a feature should be no longer considered experimental. Marking something as "experimental" usually discourages people from using a feature, specially if we don't exactly define what "experimental" means.

[RonnyPfannschmidt]

i see, i better do a discussion on the ml then

also currently only hook receivers are forward compatible

[nicoddemus]

OK, thanks!

Regarding this PR, are you OK for us to merge it? If your only concern is if we should mark it as experimental or not, we can always do it later.

only hook receivers are forward compatible

What do you mean by "hook receiver" exactly?

[RonnyPfannschmidt]

receiver is the called hook function within a plugin
the caller is the function invoking the hook
an example of a hook that needs a new argument but cant be changed is the hook for deselected test items since deselecting modifyitems hooks are are supposed to invoke it

[nicoddemus]

I now see what you mean, thanks! 😄

Just to make sure I'm not missing anything then, the new pytest_make_parametrize_id is forward compatible then right?

[RonnyPfannschmidt]

yes

[nicoddemus]

OK 👍

[coveralls]

Coverage increased (+0.009%) to 92.476% when pulling 9733127 on palaviv:parametrize-test-ids-hook into 52babba on pytest-dev:features.