Unable to add flakeheaven dependency.

[lyz-code]

• I have searched the issue tracker and believe that this is not a duplicate.

Make sure you run commands with -v flag before pasting the output.

Steps to reproduce

virtualenv env
source env/bin/activate
git clone https://github.com/lyz-code/clinv
cd clinv
git checkout feat/add-resources
pdm add -G lint flakeheaven -v

Actual behavior

The dependency is not added, and it enters in an endless loop

Could it be due to their python specifier?

[tool.poetry.dependencies]
python = "^3.6.2"

It's similar to #627 but that one was supposed to be fixed

Expected behavior

Dependency is added

Environment Information

# Paste the output of `pdm info && pdm info --env` below:
PDM version:        1.12.8
Python Interpreter: /tmp/tmp.2tKueA2EmA/env/bin/python (3.9)
Project Root:       /tmp/tmp.2tKueA2EmA/clinv
Project Packages:   None
{
  "implementation_name": "cpython",
  "implementation_version": "3.9.8",
  "os_name": "posix",
  "platform_machine": "x86_64",
  "platform_release": "4.19.0-5-amd64",
  "platform_system": "Linux",
  "platform_version": "#1 SMP Debian 4.19.37-5+deb10u1 (2019-07-19)",
  "python_full_version": "3.9.8",
  "platform_python_implementation": "CPython",
  "python_version": "3.9",
  "sys_platform": "linux"
}

[pawamoy]

Currently experiencing resolution loops as well with PDM 1.12.8. No further details yet.

[pawamoy]

We've been able to fix it on our side by removing upper bounds of internal projects' dependencies. We just fixed the symptom though!

[frostming]

It fails because flakeheaven sets a hard upper bound of importlib-metadata, causing conflicts:

Conflicts detected:
  importlib-metadata<2.0,>=1.0; python_version < "3.8" (from <Candidate flakeheaven 0.11.1 from https://pypi.org/simple/flakeheaven/>)
  importlib-metadata; python_version < "3.8" (from <Candidate click 8.0.3 from unknown>)
  importlib-metadata<4.3; python_version < "3.8" (from <Candidate flake8 4.0.1 from unknown>)
  importlib-metadata; python_version < "3.8" (from <Candidate flake8-comprehensions 3.7.0 from https://pypi.org/simple/flake8-comprehensions/>)
  importlib-metadata>=0.9; python_version < "3.8" (from <Candidate flake8-simplify 0.14.5 from https://pypi.org/simple/flake8-simplify/>)
  importlib-metadata>=0.9; python_version < "3.8" (from <Candidate flake8-typing-imports 1.11.0 from https://pypi.org/simple/flake8-typing-imports/>)
  importlib-metadata>=3.10 (from <Candidate mkdocs 1.2.3 from unknown>)
  importlib-metadata<2.0,>=1.0; python_version < "3.8" (from <Candidate flakeheaven 0.11.1 from https://pypi.org/simple/flakeheaven/>)
  importlib-metadata; python_version < "3.8" (from <Candidate click 8.0.3 from unknown>)
  importlib-metadata<4.3; python_version < "3.8" (from <Candidate flake8 4.0.1 from unknown>)
  importlib-metadata; python_version < "3.8" (from <Candidate flake8-comprehensions 3.7.0 from https://pypi.org/simple/flake8-comprehensions/>)
  importlib-metadata>=0.9; python_version < "3.8" (from <Candidate flake8-simplify 0.14.5 from https://pypi.org/simple/flake8-simplify/>)
  importlib-metadata>=0.9; python_version < "3.8" (from <Candidate flake8-typing-imports 1.11.0 from https://pypi.org/simple/flake8-typing-imports/>)
  importlib-metadata>=3.10 (from <Candidate mkdocs 1.2.3 from https://pypi.org/simple/mkdocs/>)
  importlib-metadata<2.0,>=1.0; python_version < "3.8" (from <Candidate flakeheaven 0.11.1 from https://pypi.org/simple/flakeheaven/>)
  importlib-metadata; python_version < "3.8" (from <Candidate click 8.0.3 from unknown>)
  importlib-metadata<4.3; python_version < "3.8" (from <Candidate flake8 4.0.1 from unknown>)
  importlib-metadata; python_version < "3.8" (from <Candidate flake8-comprehensions 3.7.0 from https://pypi.org/simple/flake8-comprehensions/>)
  importlib-metadata>=0.9; python_version < "3.8" (from <Candidate flake8-simplify 0.14.5 from https://pypi.org/simple/flake8-simplify/>)
  importlib-metadata>=0.9; python_version < "3.8" (from <Candidate flake8-typing-imports 1.11.0 from https://pypi.org/simple/flake8-typing-imports/>)
  importlib-metadata>=3.10 (from <Candidate mkdocs 1.2.3 from https://pypi.org/simple/mkdocs/>)
Candidate rejected: flake8-typing-imports 1.11.0

Currently, the resolver has to traverse the dependency tree back and try every older version until it can't find one satisfying the version constraints or the maximum resolution round(10000) is reached. So it looks like an infinite loop.

As a workaround, you can manually set the resolution of importlib-metadata with [tool.pdm.overrides] table. See the doc for how to do this.

[lyz-code]

Thanks for the solution @frostming