pre-commit: Add configuration to check coding style on commit

Also document the usage in CONTRIBUTING.md.

Author: schodet

.pre-commit-config.yaml

@@ -0,0 +1,14 @@
+repos:
+-   repo: local
+    hooks:
+    -   id: codeformat_c
+        name: codeformat-c
+        language: system
+        entry: poetry run ./tools/codeformat.py -cf
+        types: [c]
+    -   id: codeformat_py
+        name: codeformat-py
+        language: system
+        entry: poetry run ./tools/codeformat.py -p
+        types: [python]
+        pass_filenames: false

CONTRIBUTING.md

@@ -215,6 +215,16 @@ Before committing your changes, be sure to run:
 This will automatically fix common problems in files that follow the MicroPython
 style.
 
+This can be run automatically before making a commit using [pre-commit][]. To
+enable it, run:
+
+    poetry run pre-commit install
+
+It will install a pre-commit git hook for this repository. On every commit,
+the coding style will be checked and fixed before the commit is done.
+
+[pre-commit]: https://pre-commit.com/
+
 
 ### Logical commits
 

poetry.lock

@@ -23,6 +23,7 @@ python-dotenv = "^0.15.0"
 python-socketio = "^5.7.2"
 scipy = "^1.8.1"
 sympy = "^1.10.1"
+pre-commit = ">=3.6.2"
 
 [tool.poetry.group.stats.dependencies]
 azure-data-tables = "^12.4.2"