monorepo and version in dependencies

[paugier]

I have a very simple monorepo with two packages (fluidsim and fluidsim-core). The two packages are really twin packages and their versions always correspond, i.e. fluidsim 0.9.0 simply depends on fluidsim-core 0.9.0. They are always released together (first fluidsim-core 0.9.0 and just after fluidsim 0.9.0). There is only one tag per version in the repo.

I'd like to be able to write in fluidsim pyproject.toml:

version = '0.9.0'
dependencies = [
    "fluidsim-core==0.9.0",
    ...
]

[tool.pdm.dev-dependencies]
dev = [
   "-e fluidsim-core @ file:///${PROJECT_ROOT}/lib",
]

Unfortunately, PDM does not accept this since fluidsim-core 0.9.0 is not yet on PyPI and pdm lock gives me:

ERROR: Unable to find a resolution for fluidsim-core

However, this seems wrong since the version of fluidsim-core in the repo is indeed 0.9.0.

Is it expected? Is there a way to support this situation with PDM?