u-boot/doc/develop/python_cq.rst
Simon Glass feafc61ea6 Makefile: Add a pylint checker to the build
At present the Python code in U-Boot is somewhat inconsistent, with some
files passing pylint quite cleanly and others not.

Add a way to track progress on this clean-up, by checking that no module
has got any worse as a result of changes.

This can be used with 'make pylint'.

Signed-off-by: Simon Glass <sjg@chromium.org>
[trini: Re-generate pylint.base]
2022-01-24 17:36:15 -05:00

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.. SPDX-License-Identifier: GPL-2.0+
Python code quality
===================
U-Boot has about 60k lines of Python code, mainly in the following areas:
- tests
- pytest hooks
- patman patch submission tool
- buildman build / analysis tool
- dtoc devicetree-to-C tool
- binman firmware packaging tool
`PEP 8`_ is used for the code style, with the single quote (') used by default for
strings and double quote for doc strings. All non-trivial functions should be
commented.
Pylint is used to help check this code and keep a consistent code style. The
build system tracks the current 'score' of the source code and detects
regressions in any module.
To run this locally you should use this version of pylint::
# pylint --version
pylint 2.11.1
astroid 2.8.6
Python 3.8.10 (default, Sep 28 2021, 16:10:42)
[GCC 9.3.0]
You should be able to select and this install other required tools with::
pip install pylint==2.11.1
pip install -r test/py/requirements.txt
pip install asteval pyopenssl
Note that if your distribution is a year or two old, you make need to use `pip3`
instead.
To configure pylint, make sure it has docparams enabled, e.g. with::
echo "[MASTER]" >> .pylintrc
echo "load-plugins=pylint.extensions.docparams" >> .pylintrc
Once everything is ready, use this to check the code::
make pylint
This creates a directory called `pylint.out` which contains the pylint output
for each Python file in U-Boot. It also creates a summary file called
`pylint.cur` which shows the pylint score for each module::
_testing 0.83
atf_bl31 -6.00
atf_fip 0.49
binman.cbfs_util 7.70
binman.cbfs_util_test 9.19
binman.cmdline 7.73
binman.control 4.39
binman.elf 6.42
binman.elf_test 5.41
...
This file is in alphabetical order. The build system compares the score of each
module to `scripts/pylint.base` (which must also be sorted and have exactly the
same modules in it) and reports any files where the score has dropped. Use
pylint to check what is wrong and fix up the code before you send out your
patches.
New or removed files results in an error which can be resolved by updating the
`scripts/pylint.base` file to add/remove lines for those files, e.g.::
meld pylint.cur scripts/pylint.base
If the pylint version is updated in CI, this may result in needing to regenerate
`scripts/pylint.base`.
.. _`PEP 8`: https://www.python.org/dev/peps/pep-0008/