• Poetry version: 1.3.1
• Python version: 3.9.15

• I am on the latest stable Poetry version, installed using a recommended method.
• I have searched the issues of this repo and believe that this is not a duplicate.
• I have consulted the FAQ and blog for any relevant entries or release notes.

Issue

To give an example, with a pyproject.toml like

[tool.poetry]
name = "test"

[tool.poetry.dependencies]
numpy = { version = "^1.20.0", optional = true }

[tool.poetry.extras]
my_extra = ["numpy "]

poetry lock, poetry check and poetry install -E my_extra all run without any error or anything. But they wouldn't install the numpy dependency. This is because there's an extra space in my_extra = ["numpy "] that means the extra isn't matched to the dependency. This would happen with any misspelling in the my_extra list. So poetry just silently ignores entries in extras that can't be matched to a dependency.

The poetry.lock file would just have a sections like

[extras]
my_extra = []

in this case.

It'd be nice to at least get a warning in poetry lock or poetry check when an extra item doesn't match a dependency. These types of errors can be hard to spot and can take a while to figure out.