Poetry add does not resolve the correct package version given the project constraints

[snejus]

• Poetry version: 1.2.2
• Python version: 3.9.13
• OS version and name: Arch Linux
• pyproject.toml: https://github.com/snejus/rich-tables/blob/main/pyproject.toml

• 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.
• If an exception occurs when executing a command, I executed it again in debug mode (-vvv option) and have included the output below.

Issue

Currently, an attempt to add a dependency

• without a version constraint and
• which does not anymore support the lowest python version that the project supports

produces an error:

$ poetry add multimethod                                                                        
Using version ^1.9 for multimethod

Updating dependencies
Resolving dependencies... (0.0s)

The current project's Python requirement (>=3.6.3,<4) is not compatible with some of the required packages Python requirement:
  - multimethod requires Python >=3.7, so it will not be satisfied for Python >=3.6.3,<3.7

Because multimethod (1.9) requires Python >=3.7
 and no versions of multimethod match >1.9,<2.0, multimethod is forbidden.
So, because rich-tables depends on multimethod (^1.9), version solving failed.
...

In this case,

• the project requires python = ">=3.6.3,<4"
• the dependency requires python >= 3.7 (one of the recent releases)
• the dependency used to support python3.6

Given that poetry add documentation says

If you do not specify a version constraint, poetry will choose a suitable one based on the available package versions.

I would expect poetry to check all previous dependency versions and use the one that fits my project constraints, if it exists. Instead, now it implicitly looks for a recent version: Using version ^1.9 for multimethod.

This can now be achieved by adding multimethod = "*" and running poetry update and I'd expect poetry add to match this behaviour when the dependency version is not specified.

[dimbleby]

duplicate #707, among others

[snejus]

I thought this must have been mentioned somewhere, but failed use the right search terms! Thanks

[github-actions]

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