Editable installs fail when poetry.core is declared as build-system

I have created a minimal package to demonstrate this problem (which I have in a real library).

test_editable/
- test_editable/
-- __init__.py
- pyproject.toml #generated with poetry init
- setup.py # shim

The setup.py file is:

import setuptools

if __name__ == "__main__":
    setuptools.setup(name="test_editable")   # without the name the package is installed as UNKNOWN

The pyproject.toml file is:

[tool.poetry]
name = "test_editable"
version = "0.1.0"
description = "test poetry editable problem"
authors = ["albertogomcas"]
license = "mit"

[tool.poetry.dependencies]
python = "^3.6"

[tool.poetry.dev-dependencies]

[build-system]
#requires = ["poetry>=0.12"]
#build-backend = "poetry.masonry.api"
requires = ["poetry-core>=1.0.0a3"]
build-backend = "poetry.core.masonry.api"

As is above, pip install -e . fails with:

Looking in indexes: https://pypi.org/simple
Obtaining file:///C:/test_editable
  Installing build dependencies ... done
  Getting requirements to build wheel ... done
    Preparing wheel metadata ... done
Installing collected packages: test-editable
  Attempting uninstall: test-editable
    Found existing installation: test-editable 0.1.0
    Uninstalling test-editable-0.1.0:
      Successfully uninstalled test-editable-0.1.0
  Running setup.py develop for test-editable
    ERROR: Command errored out with exit status 1:
     command: 'c:\winpython64-master@66fb39fabeb\wpy64-3680\python-3.6.8.amd64\python.exe' -c 'import sys, setuptools, tokenize; sys.argv[0] = '"'"'C:\\test_editable\\setup.py'"'"'; __file__='"'"'C:\\test_editable\\setup.py'"'"';f=getattr(tokenize, '"'"'open'"'"', open)(__file__);code=f.read().replace('"'"'\r\n'"'"', '"'"'\n'"'"');f.close();exec(compile(code, __file__, '"'"'exec'"'"'))' develop --no-deps
         cwd: C:\test_editable\
    Complete output (3 lines):
    Traceback (most recent call last):
      File "<string>", line 1, in <module>
    ModuleNotFoundError: No module named 'setuptools'
    ----------------------------------------
  Rolling back uninstall of test-editable

However, if I comment the build system lines with core and use instead the upper two:

Looking in indexes: https://pypi.org/simple
Obtaining file:///C:/test_editable
  Installing build dependencies ... done
  Getting requirements to build wheel ... done
    Preparing wheel metadata ... done
Installing collected packages: test-editable
  Attempting uninstall: test-editable
    Found existing installation: test-editable 0.1.0
    Uninstalling test-editable-0.1.0:
      Successfully uninstalled test-editable-0.1.0
  Running setup.py develop for test-editable
Successfully installed test-editable

I believe the option that works is actually deprecated (?)

[finswimmer]

Editable installs for PEP-517 compliant backend wasn’t possible for a long time, because it wasn’t defined how to do this. This has changed with PEP 660. The hook is already implemented in poetry-core’s master branch.

[brechtm]

I couldn’t get this working. There are two issues with the suggestions described above:

1. The minimal setup.py does not register entry points (‘plugins’ in pyproject.toml)
2. python /path/to/another_project/setup.py develop does not result in a working editable installation of another_project (the CWD path is written to the .pth files in the virtualenv)

I miss being able to editable-install my Poetry-managed project into an arbitrary virtualenv for debugging purposes. I now need to fall back to installing in non-editable mode over and over.