poetry: Poetry 1.2 lockfiles can't always be installed by Poetry 1.1

For version details etc, see repro below.

Issue

Poetry 1.2 can create lockfiles that aren’t installable by Poetry 1.1 due to different handling of . characters in dependency names.

If the configured repository uses the “simple” repository API, Poetry 1.2 replaces . characters with - characters in the name field of dependencies in the lockfile. Poetry 1.1 fails to install from this lockfile with a SolverProblemError.

I’m not sure what guarantees, if any, Poetry makes about lockfile compatibility between Poetry versions. This isn’t a “breaking” change, as such, but makes interoperability painful in cases where the Poetry version can’t be upgraded “atomically”. It might be that this just isn’t supported, in which case a “fix” might be a quick note in the changelog or something.

I’ve got a Docker-based repro using ruamel.yaml:

# syntax=docker/dockerfile:1.3-labs
FROM python:3.8 as poetry1.2
RUN pip install poetry==1.2.1
COPY <<"EOF" /src/pyproject.toml
[tool.poetry]
name = "dotdash"
version = "0.1.0"
description = ""
authors = [""]

[tool.poetry.dependencies]
python = "^3.8"
"ruamel.yaml" = "*"

[[tool.poetry.source]]
name = 'simple'
url = 'https://pypi.org/simple'
default = true

EOF
RUN cd /src && poetry lock

FROM python:3.8 as poetry1.1
RUN pip install poetry==1.1.15
COPY --from=poetry1.2 /src/ /src/
RUN cd /src && poetry install

which produces:

 => ERROR [poetry1.1 4/4] RUN cd /src && poetry install                                                         1.9s
------
 > [poetry1.1 4/4] RUN cd /src && poetry install:
#15 0.995 Creating virtualenv dotdash-VsnhxLU2-py3.8 in /root/.cache/pypoetry/virtualenvs
#15 1.569 Installing dependencies from lock file
#15 1.706
#15 1.706   SolverProblemError
#15 1.706
#15 1.706   Because dotdash depends on ruamel.yaml (*) which doesn't match any versions, version solving failed.
#15 1.706
#15 1.707   at /usr/local/lib/python3.8/site-packages/poetry/puzzle/solver.py:241 in _solve
#15 1.732       237│             packages = result.packages
#15 1.732       238│         except OverrideNeeded as e:
#15 1.732       239│             return self.solve_in_compatibility_mode(e.overrides, use_latest=use_latest)
#15 1.733       240│         except SolveFailure as e:
#15 1.733     → 241│             raise SolverProblemError(e)
#15 1.733       242│
#15 1.733       243│         results = dict(
#15 1.733       244│             depth_first_search(
#15 1.734       245│                 PackageNode(self._package, packages), aggregate_package_nodes

Ignore the non-standard install method for Poetry - I’ve also tested with the recommended method, I’m just being lazy in the Dockerfile.