Poetry doesn't respect version specifiers in Requires-Dist for dependencies

• I am on the latest Poetry version.
• I have searched the issues of this repo and believe that this is not a duplicate.
• If an exception occurs when executing a command, I executed it again in debug mode (-vvv option).

• OS version and name: Windows 10 2004
• Poetry version: 1.0.10
• Link of a Gist with the contents of your pyproject.toml file: https://gist.github.com/f0ff886f/3178ffdf080e67a5fdfa3fcbd5503d31

Issue

poetry add rich@latest

...

[SolverProblemError]
The current project's Python requirement (^3.6) is not compatible with some of the required packages
Python requirement:
  - dataclasses requires Python >=3.6, <3.7

Because no versions of rich match >7.0.0,<8.0.0
 and rich (7.0.0) depends on dataclasses (>=0.7,<0.8), rich (>=7.0.0,<8.0.0) requires dataclasses (>=
0.7,<0.8).
Because dataclasses (0.7) requires Python >=3.6, <3.7
 and no versions of dataclasses match >0.7,<0.8, dataclasses is forbidden.
Thus, rich is forbidden.

This is related to but doesn’t seem to be directly addressed by the many “Python requirement (^3.6) is not compatible with some of the required packages” issues. Closest issue is https://github.com/python-poetry/poetry/issues/2840 and the solution https://github.com/python-poetry/poetry/issues/1930#issuecomment-653906544 doesn’t apply here.

My library is expressing it is compatible with Python ^3.6, which I understand as >=3.6.0, < 4.0.0.

It requires the https://github.com/willmcgugan/rich library which is compatible also with Python ^3.6. The issues starts with Rich’s dependency on dataclasses which started to throw a wrench in many people’s plans it seems by declaring its Python requirement as >=3.6, <3.7 (^3.7 has dataclasses built in).

Now Rich declares its dependency like so: Requires-Dist: dataclasses (>=0.7,<0.8); python_version >= "3.6" and python_version < "3.7"

When dataclasses is added as a dependency with python_version ~3.6 directly to this project, it resolves dataclasses just fine (which I understand is just shorthand for >=3.6, <3.7).

But now, when Rich tries to do the same, and I depend on Rich, everything breaks and cannot continue.

The posted solution says to use python_version specifiers, but I cannot do that for Rich, but Rich itself does that and Poetry seems to ignore it.

The workaround is to manually specify rich = "^7.0.0" in the [tool.poetry.dependencies] and then something like poetry update works just fine.

[f0ff886f]

Hello, thank you for the work in 1.1.0rc1! I can confirm this bug is gone and I have a fully working and perfectly working Poetry!

[f0ff886f]

@abn downgrading to 1.1.0b2 solved the dependency resolution! BUT… now I hit the exact same problem as in https://github.com/python-poetry/poetry/issues/2911 so that also does not work (every installation of a dependency fails).

So 1.1.0b3 doesn’t respect the dependency’s python_version, and 1.1.0b2 causes errors on every dependency installation.

I’ll just wait for 1.1.0b5… 👍 I really appreciate the help.