Poetry transient extra dependency resolution bug

pyproject.toml

[tool.poetry]
name = "test"
version = "0.1.0"
description = ""
authors = ["a b <[email protected]>"]

[tool.poetry.dependencies]
python = "^3.8"
ufolib2 = "^0.6"
poetry-resolver-bug-test = "*"

[tool.poetry.dev-dependencies]
isort = {version = "^4.3.21", extras = ["pyproject"]}

[[tool.poetry.source]]
name = "test"
url = "https://test.pypi.org/simple/"
secondary = true

[build-system]
requires = ["poetry>=0.12"]
build-backend = "poetry.masonry.api"