Appendix: Converting existing configurations
The tools we have seen in the tutorial can read their configuration from
a variety of file formats.
Before pyproject.toml became standard, many projects used different files,
and some continue to do so.
This appendix has you migrate from older-style configurations to using
pyproject.toml. It also discusses some additional tools which were
not mentioned in the main tutorial.
The starter code comes with some sample configurations in the old-configs
directory.
Packaging
The dependencies and other project metadata are provided in setup.py.
Move that to the [project] table of pyproject.toml.
The setup.py format is not deprecated, although commands like
python setup.py install and python setup.py develop are no longer favoured.
Instead, you should use pip to install a package from source.
PyPA has a guide for modernizing setup.py-based projects.
Linting
Ruff uses TOML files for configuration (either its own ruff.toml
or pyproject.toml), but older linters look for a number of filenames.
Two sample configurations are provided in pylintrc and .flake8,
for Pylint and Flake8 respectively.
Pylint supports pyproject.toml, so you can recreate the same configuration
in that file.
On the other hand, Flake8 cannot be configured in pyproject.toml.
However, Ruff supports the whole set of Flake8 rules in
its own rules, so you can construct an equivalent configuration
for Ruff.
Formatting
The black formatter can be configured only in pyproject.toml.
The isort utility can be configured with various files,
including pyproject.toml and .isort.cfg (as in the sample config).
The formats are very similar.
If using Ruff for linting, you may also want to use it for auto-formatting.
Currently, Ruff implements the isort rules under its linter, in the "I"
rules category. You can recreate the configuration from .isort.cfg
in Ruff, as indicated in its docs.
Type checking
Mypy can store configuration in pyproject.toml or an ini file.
The two formats are very similar, with the main difference being the name
of the sections, particularly for overrides.
You should therefore be able to recreate the configuration from mypy.ini.
You can read more on the differences in the mypy docs,
which also contain an example pyproject.toml.