Add back notes about editable install and pyproject metadata

On further examination, `pip` seems to fail if `setup.py` is missing.

1 files changed, 12 insertions, 0 deletions

diff --git a/docs/userguide/pyproject_config.rst b/docs/userguide/pyproject_config.rst
index a139fa73..3988db2f 100644
--- a/docs/userguide/pyproject_config.rst
+++ b/docs/userguide/pyproject_config.rst
@@ -12,6 +12,18 @@ Configuring setuptools using ``pyproject.toml`` files
    ``setuptools`` via ``pyproject.toml`` files is still experimental and might
    change (or be removed) in future releases.
 
+.. important::
+   For the time being, ``pip`` still might require a ``setup.py`` file
+   to support :doc:`editable installs <pip:cli/pip_install>`.
+
+   A simple script will suffice, for example:
+
+   .. code-block:: python
+
+       from setuptools import setup
+
+       setup()
+
 Starting with :pep:`621`, the Python community selected ``pyproject.toml`` as
 a standard way of specifying *project metadata*.
 ``Setuptools`` has adopted this standard and will use the information contained