add precommit-yaml config

.pre-commit-config.yaml

@@ -0,0 +1,86 @@
+exclude: "^LICENSES"
+
+repos:
+  - repo: https://github.com/pre-commit/pre-commit-hooks
+    rev: v4.3.0
+    hooks:
+      - id: check-merge-conflict
+      - id: end-of-file-fixer
+      - id: fix-encoding-pragma
+      - id: mixed-line-ending
+      - id: trailing-whitespace
+      - id: check-added-large-files
+        args: ["--maxkb=2000"]
+
+  # Sort package imports alphabetically
+  - repo: https://github.com/PyCQA/isort
+    rev: 5.10.1
+    hooks:
+      - id: isort
+        args: ["--profile", "black", "--filter-files"]
+
+  # Convert relative imports to absolute imports
+  - repo: https://github.com/MarcoGorelli/absolufy-imports
+    rev: v0.3.1
+    hooks:
+      - id: absolufy-imports
+
+  # Find common spelling mistakes in comments and docstrings
+  - repo: https://github.com/codespell-project/codespell
+    rev: v2.2.1
+    hooks:
+      - id: codespell
+        args: [
+            '--ignore-regex="(\b[A-Z]+\b)"',
+          ] # Ignore capital case words, e.g. country codes
+        types_or: [python, rst, markdown]
+        files: ^(scripts|doc)/
+
+  # Make docstrings PEP 257 compliant
+  - repo: https://github.com/myint/docformatter
+    rev: v1.5.0
+    hooks:
+      - id: docformatter
+        args:
+          ["--in-place", "--make-summary-multi-line", "--pre-summary-newline"]
+
+  - repo: https://github.com/keewis/blackdoc
+    rev: v0.3.5
+    hooks:
+      - id: blackdoc
+
+  # Formatting with "black" coding style
+  - repo: https://github.com/psf/black
+    rev: 22.8.0
+    hooks:
+      # Format Python files
+      - id: black
+      # Format Jupyter Python notebooks
+      - id: black-jupyter
+
+  # Remove output from Jupyter notebooks
+  - repo: https://github.com/aflc/pre-commit-jupyter
+    rev: v1.2.1
+    hooks:
+      - id: jupyter-notebook-cleanup
+        args: ["--remove-kernel-metadata"]
+
+  # Do YAML formatting (before the linter checks it for misses)
+  - repo: https://github.com/macisamuele/language-formatters-pre-commit-hooks
+    rev: v2.4.0
+    hooks:
+      - id: pretty-format-yaml
+        args: [--autofix, --indent, "2", --preserve-quotes]
+
+  # Format Snakemake rule / workflow files
+  - repo: https://github.com/snakemake/snakefmt
+    rev: 0.4.4
+    hooks:
+      - id: snakefmt
+
+  # For cleaning jupyter notebooks
+  -   repo: https://github.com/aflc/pre-commit-jupyter
+      rev: v1.2.1
+      hooks:
+      -   id: jupyter-notebook-cleanup
+          exclude: examples/solve-on-remote.ipynb

doc/contributing.rst

@@ -16,7 +16,17 @@ to our `GitHub repository <https://github.com/PyPSA/PyPSA-Eur>`_.
 * If you start working on a feature in the code, let us know by opening an issue or a draft pull request.
   This helps all of us to keep an overview on what is being done and helps to avoid a situation where we
   are doing the same work twice in parallel.
-* We encourage you to use the `PEP 8 coding style <https://www.python.org/dev/peps/pep-0008/>`_.
+
+For linting, formatting and checking your code contributions
+against our guidelines (e.g. we use `Black <https://github.com/psf/black>`_ as code style
+use `pre-commit <https://pre-commit.com/index.html>`_:
+
+1. Installation ``conda install -c conda-forge pre-commit`` or ``pip install pre-commit``
+2. Usage:
+    * To automatically activate ``pre-commit`` on every ``git commit``: Run ``pre-commit install``
+    * To manually run it: ``pre-commit run --all``
+
+Note that installing `pre-commit` locally is not strictly necessary. If you create a Pull Request the `pre-commit CI` will be triggered automatically and take care of the checks.
 
 For all code contributions we follow the four eyes principle (two person principle), i.e. all suggested code
 including our own are reviewed by a second person before they are incoporated into our repository.