A flake8 plugin that enforces opinionated Python coding conventions for clean, maintainable code.
Stolid encourages:
Composition over inheritance
Dependency injection over mocking
Protocol-based typing over abstract base classes
Immutable dataclasses
Small, focused functions and classes
Installation
pip install stolid
Usage
Run stolid as a module to check your code:
python -m stolid your_package/
python -m stolid is the unified entry point. It runs the flake8 plugin (which emits every per-file SLDxxx code) and then the cross-file scanners that produce the SLD80x public-contract diagnostics, exiting with the worst of the two stages’ exit codes. Paths default to . if none are given.
Running flake8 directly still works and is fine for editor integration, but it only loads the in-file plugin — the SLD80x cross-file checks require the workspace-wide view that python -m stolid provides:
flake8 your_code.py # in-file SLDxxx only, no SLD80x
Error Codes
Every diagnostic is an SLDxxx code, grouped by leading digit so a whole family can be reasoned about — or silenced — together:
SLD1xx — testing and dynamic execution: no unittest.mock.patch, no exec / eval / __import__.
SLD2xx — abstract base classes: prefer Protocol over ABC, and keep any single module’s imported surface narrow.
SLD3xx — object-oriented design: boring constructors, no private methods, and real enums instead of stringly-typed values.
SLD4xx — inheritance: no subclassing of concrete classes.
SLD5xx — dataclass configuration: frozen, slots, and kw_only on every dataclass.
SLD6xx — code complexity: bounded function weight, argument and method counts, context-manager-friendly cleanup, and enumerate / iteration over manual range(len(...)) and while-index walks.
SLD7xx — naming: no vague words, no shadowing of stdlib names, no confusable near-duplicate names.
SLD8xx — cross-file contracts, documentation, and import-graph architecture: the checks that need a workspace-wide view and run via python -m stolid.
SLD9xx — privacy: the underscore-prefix convention across attributes, modules, and imports.
The full catalog — every code with its rationale and bad/good examples — lives in the documentation under doc/error-codes/ (one page per family).
Configuration
Stolid follows standard flake8 configuration. Add to your setup.cfg or .flake8:
[flake8]
extend-ignore = SLD301,SLD302
Or use per-file ignores:
[flake8]
per-file-ignores =
tests/*:SLD301,SLD302
Development
pip install nox
# Run all checks
nox
# Run specific sessions
nox -s tests # Run tests with coverage
nox -s lint # Run black and flake8
nox -s mypy # Run type checking
License
MIT License. See LICENSE for details.
Release files for stolid 2026.5.31.2051
For a detailed explanation of source distributions (sdists) and built distributions (wheels), please see the package formats documentation.
Source distribution (sdist)
| File | Size | Uploaded | |
|---|---|---|---|
| stolid-2026.5.31.2051.tar.gz | 95.0 kB | Details |
Built distribution (wheel)
| File | Interpreter | ABI | Platform | Reset |
|---|---|---|---|---|
| stolid-2026.5.31.2051-py3-none-any.whl | Python 3 | none | any | Details |
Total release size: 223.3 kB
Release files / stolid-2026.5.31.2051.tar.gz
| Download URL | stolid-2026.5.31.2051.tar.gz |
|---|---|
| Size | 95.0 kB |
| Tags | Source |
|
SHA-256 checksum How to use checksums |
231f14294e1c2f5d48d9624d60098f717da79b50e90a442001e3749271e6f8f4
|
|
BLAKE2b-256 checksum How to use checksums |
d321a155c50b0abf32c2a98d53dbf12c328997bad930363d0c6101355c8ac139
|
| Upload date | |
|
Uploaded using Trusted Publishing? What is trusted publishing? |
Yes |
| Uploaded via |
twine/6.1.0 CPython/3.13.13
|
Provenance
Provenance describes where a file came from. On PyPI, provenance is shared via attestations, which provide a verifiable record of the build or publishing details. View details, limitations and caveats.
PyPI Publish Attestation
PyPI verified that this artifact, at this checksum, originated from the publisher listed below.
Signed by GitHub Actions, verified by PyPI on May 31, 2026.
Transparency logRelease files / stolid-2026.5.31.2051-py3-none-any.whl
| Download URL | stolid-2026.5.31.2051-py3-none-any.whl |
|---|---|
| Size | 128.3 kB |
| Tags | Python 3 |
|
SHA-256 checksum How to use checksums |
4fb515ebc067349a7e7b5144f81ac53f70de035560a9e1e0fc6cd5c138a66394
|
|
BLAKE2b-256 checksum How to use checksums |
1ad4bccc4451eccfd3b4512a31efc9e0dee9bed14a5ecf868d10740baacd1b58
|
| Upload date | |
|
Uploaded using Trusted Publishing? What is trusted publishing? |
Yes |
| Uploaded via |
twine/6.1.0 CPython/3.13.13
|
Provenance
Provenance describes where a file came from. On PyPI, provenance is shared via attestations, which provide a verifiable record of the build or publishing details. View details, limitations and caveats.
PyPI Publish Attestation
PyPI verified that this artifact, at this checksum, originated from the publisher listed below.
Signed by GitHub Actions, verified by PyPI on May 31, 2026.
Transparency log