Feature request: activate extras in group dependencies

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• I have searched the FAQ and general documentation and believe that my question is not already covered.

Feature Request

Hello! I cannot believe someone did not ask it before, but I really couldn't find, so here is my question / feature question: is it possible to activate extra dependencies in groups?

To my knowledge, it seems like it is not possible, but I would love to see this feature (but maybe this is not possible due to how pip and Poetry are implemented).

Example

Let say a have some package with extras dependencies. I also have a test group, that must activate all extras since I want to test the main package with all its features.

[tool.poetry.dependencies]
a = "1"
b = {version = "1", optional = true}

[tool.poetry.extras]
extra-feature = ["b"]

[tool.poetry.group]
optional = true

[tool.poetry.group.test.dependencies]
pytest = "1"
b = "1"

Instead of duplicating all my extra dependencies, I'd love to just say that group test needs extra-feature.

For example:

[tool.poetry.dependencies]
a = "1"
b = {version = "1", optional = true}

[tool.poetry.extras]
extra-feature = ["b"]

[tool.poetry.group]
optional = true
extras = ["extra-feature"]

[tool.poetry.group.test.dependencies]
pytest = "1"

For people that know, Rust actually does that (extras are called features) very well.

Start by reviewing how Poetry represents dependency groups and extras, then inspect the related dependency-resolution and packaging tests. Compare the proposed group configuration with the existing TOML behavior and define how activating an extra through a group should affect resolution and installation. Done means the behavior is specified, implemented, and covered by tests.