`poetry export` generates wrong source flags

• Poetry version: 1.5.1
• Python version: 3.10
• OS version and name: Ubuntu 20.04.6
• pyproject.toml:

[tool.poetry]
name = "mypkg"
version = "0.1.0"
description = ""
authors = [""]
readme = "README.md"
packages = []

[tool.poetry.dependencies]
python = "~3.10"
torch-scatter = { version = "2.1.1", source = "pyg-cuda" }
torch-sparse = { version = "0.6.17", source = "pyg-cuda" }


[[tool.poetry.source]]
name = "PyPI"
priority = "primary"


[[tool.poetry.source]]
name = "pyg-cuda"
url = "https://data.pyg.org/whl/torch-2.0.0+cu118.html"
priority = "primary"


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

• 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

The poetry export command can not distinguish between --extra-index-url and --find-links as their source definitions are the same.
To be specific, when I run poetry export --without-hashes > requirements.txt, this is what it generates:

--extra-index-url https://data.pyg.org/whl/torch-2.0.0+cu118.html

numpy==1.25.0 ; python_version >= "3.10" and python_version < "3.11"
scipy==1.11.1 ; python_version >= "3.10" and python_version < "3.11"
torch-scatter==2.1.1+pt20cu118 ; python_version >= "3.10" and python_version < "3.11"
torch-sparse==0.6.17+pt20cu118 ; python_version >= "3.10" and python_version < "3.11"

Then, pip install -r requirements.txt gives the following error:

ERROR: Could not find a version that satisfies the requirement torch-scatter==2.1.1+pt20cu118 (from versions: 0.3.0, 1.0.2, 1.0.3, 1.0.4, 1.1.0, 1.1.1, 1.1.2, 1.2.0, 1.3.0, 1.3.1, 1.3.2, 1.4.0, 2.0.2, 2.0.3, 2.0.4, 2.0.5, 2.0.6, 2.0.7, 2.0.8, 2.0.9, 2.1.0, 2.1.1)
ERROR: No matching distribution found for torch-scatter==2.1.1+pt20cu118

This is because the https://data.pyg.org/whl/torch-2.0.0+cu118.html is supposed to be a --find-links url rather than --extra-index-url or --index-url. Apparently, poetry does not tell the difference due to their same definition.

Start with the poetry export --without-hashes reproduction and the provided pyproject.toml; compare the generated requirements.txt source flag with the configured pyg-cuda source. Done means the export distinguishes a find-links source from an extra index and the resulting requirements file installs the listed packages with pip.