Poetry requires version info in pyproject.toml when build tooling does this dynamically

[Evan0000000000]

Opening this as a discussion initially since I'm not really sure if this is a bug, new feature, or just ambiguity in how pyproject.toml is defined.

I'm using poetry in a corporate environment and have no control over the build pipeline. The pipeline expects my pyproject.toml to contain both of these:

[project]
dynamic = ["version"]
[tool.setuptools.dynamic]
version = { attr = "package_name.__version__" }

and then in the __init__.py of the package:

__version__ = '0.0.0'

(as far as I understand it from there the build system injects the version in that location as it builds the wheel but that's neither here nor there)

With this arrangement poetry gives the following error when I try to poetry lock

The Poetry configuration is invalid:
  - Either [project.version] or [tool.poetry.version] is required in package mode.

Now I could add either of those with a dummy version number and be done with it, but that seems less than ideal since this the whole point of this file is to have accurate metadata about the project. If I controlled the pipeline I imagine I could inject the version number into pyproject.toml as well, but I can't effect that change.

Has anyone else run into this, and if so what did you do?

[radoering]

As far as I know, defining project.version when you have declared it as dynamic is wrong. Thus, you should use tool.poetry.version to define a dummy version. Further, project.version may be picked up by your build-backend whereas tool.poetry.version will only be considered by Poetry / poetry-core.

Historically, poetry-core was the only build-backend supported by Poetry - and poetry-core requires one of both versions to be defined in the pyproject.toml. Although, with Poetry 2.2, altnernative build-backends are supported by poetry build, other commands still consider poetry-core as the build-backend. E.g., when running poetry install or poetry sync for a project with package-mode = true, which is the default, an editable install of the project is done - and this editable install does not consider the real build-backend to determine the version. Thus, it requires the version from the pyproject.toml. (The version is required to write the .dist-info directory.)