feat: Create features and environments from extras

[olivier-lacroix]

fixes #1062

[olivier-lacroix]

Is this OK?

Or do we want to add it to the 'default' solve-group? That is, the following

[environments]
default = ["somefeature"]

Would be parsed as if the TOML contained

[environments]
default = { features = ["somefeature"], solve-group = "default" } 

[olivier-lacroix]

@ruben-arts @baszalmstra any thought on this PR?

[ruben-arts]

I like it, it relatively simple and small but behaves like the [project.dependencies] which I am for. The ability to overwrite and extend using the normal pixi feature tables is also nice.

[baszalmstra]

Also create a "default" solve group, associated to the default environment, as per comment.

Can you link that comment? I am unable to find it.

I dont think I agree with this because it feels weird to me that for all other environments you do always have to be explicit about solve-groups.

[olivier-lacroix]

@baszalmstra there you go: #1077 (comment)

[ruben-arts]

I'm sorry for the confusement @olivier-lacroix, @baszalmstra kinda convinced me outside of this thread. Lets put the default = {features = [], solve-group = "default"} back in. It's easier to make this implicit after having it explicit then the other way around.
As making this implicit is a breaking change. Because in theory user could already be using the "default" solve-group for non-default environments.

[olivier-lacroix]

@ruben-arts no worries, I reverted that bit. I also:

• Refactored the parsing of pyproject.toml in init.rs to take advantage of the new custom TomlError
• Added an info message about the created environments if any (to align with what was done re. the install of the package itself).
• Added an info message when pixi init is run against a pyproject.toml that contains a pixi section already
• Filtered unused features out
• Updated the flask example

[ruben-arts]

Thanks @olivier-lacroix !

[dhirschfeld]

With the above, is it correct that installing the test environment with pixi would install pytest from pypi rather than conda-forge?

If I wanted my pixi test environment to only install dependencies from conda-forge can I specify that?

[olivier-lacroix]

@dhirschfeld you are correct.

Currently, you would have to manually add them to the tool.pixi.feature.test.dependencies table. What you want is also on my wishlist :-) #532

[dhirschfeld]

So, if I did manually specify the test dependencies in [tool.pixi.feature.test.dependencies] table, then that would be used instead of mapping pypi dependencies from the [project.optional-dependencies] table?

[olivier-lacroix]

Yes. Pixi currently solves pypi dependencies after the conda ones. And if it detects a package is already provided by one of the conda packages requested, it is skipped.