poetry export requirements.txt produces an invalid constraint file

[shadycuz]

• Poetry version: 1.2.1
• Python version: 3.9.14
• OS version and name: 20.04
• pyproject.toml: update poetry version DontShaveTheYak/cloud-radar#160

• 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

Before upgrading to poetry 1.2.1, I was using 1.1.4. In my CICD pipeline I had nox installing my dependencies by having poetry export a requirements.txt. This was the command nox would run.

$ poetry export --with dev --format=requirements.txt --without-hashes --output=/tmp/tmpzi691uyz

It then ran this command:

$ python -m pip install --constraint=/tmp/tmpke1yt5pq flake8 flake8-black flake8-bugbear flake8-import-order

This used to work correctly but now I get this:

$ nox > Command python -m pip install --constraint=/tmp/tmpke1yt5pq flake8 flake8-black flake8-bugbear flake8-import-order failed with exit code 1:
DEPRECATION: Constraints are only allowed to take the form of a package name and a version specifier. Other forms were originally permitted as an accident of the implementation, but were undocumented. The new implementation of the resolver no longer supports these forms. A possible replacement is replacing the constraint with a requirement. Discussion can be found at https://github.com/pypa/pip/issues/8210
ERROR: Constraints cannot have extras
nox > Session lint-3.9 failed.

When I cat the requirements file I see coverage twice (its the only dependency I have where I use an "extra").

coverage==6.4.4 ; python_version >= "3.8" and python_version < "4.0"
coverage[toml]==6.4.4 ; python_version >= "3.8" and python_version < "4.0"

I don't know why its listed twice. I do know that the generated file does install correctly from a new venv, so its only broken when used as a constraint file.

[Secrus]

Moved the issue to export plugin repo, as it belongs here. As far as I am aware, export produces valid requirements.txt file, not constraint file. See #125.

@dimbleby you know more about export plugin. Could you confirm?

[dimbleby]

yeah, I think this just duplicates #125

[shadycuz]

Even more surprising, I have removed all instances of coverage[toml] and replaced it with coverage and yet I still end up with the coverage[toml] in the poetry.lock file. I even removed and reinstalled my poetry virtual environment. =/

[Secrus]

Even more surprising, I have removed all instances of coverage[toml] and replaced it with coverage and yet I still end up with the coverage[toml] in the poetry.lock file. I even removed and reinstalled my poetry virtual environment. =/

You have pytest-cov in your dependencies and it requires coverage[toml] itself.

[shadycuz]

I will close this as its a duplicate of #125 as mentioned above. If you are trying to do what I am doing, which is to get only the dev dependencies installed then you can now use poetry --only dev, which is what I switched to in my export command poetry export --only dev. More details for nox users here.

[neersighted]

Worth noting (obviously, this is also stated on the linked issues) that constraints.txt is not requirements.txt, for those that come here in the future. There are differences in what is allowed in the format, and proper support will require a new exporter. sed is a workaround in the mean time for most cases.