install_with_constraints fails with the new poetry 1.1.0

First of all big thanks for an excellent example for Python project tooling!

Have you also noticed this problem with latest poetry update? poetry 1.1.0 nox 2020.8.22

❯ nox -rs black
nox > Running session black
nox > Re-using existing virtual environment at .nox/black.
nox > poetry export --dev --format=requirements.txt --output=/var/folders/qj/sjb9y3s56sj1s60cwhmhln3cy765d7/T/tmp57tr87b4

  IndexError

  list index out of range

  at ~/.pyenv/versions/3.8.1/lib/python3.8/site-packages/poetry/utils/exporter.py:76 in _export_requirements_txt
       72│             if not dev
       73│             else self._poetry.package.all_requires,
       74│             with_nested=True,
       75│         ):
    →  76│             package = repository.find_packages(dependency=dependency)[0]
       77│
       78│             # If a package is optional and we haven't opted in to it, continue
       79│             if package.optional and package.name not in extra_package_names:
       80│                 continue
nox > Command poetry export --dev --format=requirements.txt --output=/var/folders/qj/sjb9y3s56sj1s60cwhmhln3cy765d7/T/tmp57tr87b4 failed with exit code 1
nox > Session black failed.

It works fine if downgrading poetry to 1.0.5. Strangely running below command directly i.e. not in nox session works with poetry 1.1.0.

❯ poetry export --dev --format=requirements.txt --output=/var/folders/qj/sjb9y3s56sj1s60cwhmhln3cy765d7/T/tmp57tr87b4

[villekr]

https://github.com/python-poetry/poetry/issues/3063. Not an issue with this repository code. Just to be aware of this if following atm.

[darth-veitcher]

I think this is still a problem. See https://github.com/python-poetry/poetry-plugin-export/issues/126

When you have dependencies such as pylama[lint] or coverage[toml] it will fail with the following error message:

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