poetry sync (editable mode) doesn't handle/allow custom *.pth files

Issue Kind

Brand new capability

Description

The wheel build via poetry build includes custom *.pth files, but they are not installed in editable mode, and there doesn't seem to be an option to enforce this (also couldn't find anything in the source that might do it).

Code references for editable wheel build (which is later installed to the virtualenv):

• https://github.com/python-poetry/poetry-core/blob/eee84d755cf3ac4573efa552cec283d4e7f8758e/src/poetry/core/masonry/builders/wheel.py#L127-L146
  • it creates a $PROJECT.pth-file linking the "editable" packages (actually their base directory, i.e. the "src" folder from the source) into the virtualenv (this works for finding *.py files, but not *.pth)
  • _build() doesn't do anything with the wheel in editable mode
  • _copy_file_scripts() only installs script files into a data/scripts subfolder.
  • dist-info / metadata is a subfolder too

Impact

I use *.pth-files to initialize the environment; this is an application and is always installed in its own virtualenv, so there is no downside, but it makes life much easier.

Workarounds

With hatch instead of poetry I can install *.pth-files using [tool.hatch.build.targets.wheel.force-include].

Start in poetry-core's src/poetry/core/masonry/builders/wheel.py, especially the editable wheel build references in _build() and _copy_file_scripts(). Compare how custom *.pth files are included by poetry build with the editable path, then determine how editable installation should preserve those files. Done means custom *.pth files are installed in editable mode as well as in the regular wheel.