Flake8 Extension to enforce better comma placement.
Note: Black, the uncompromising Python code formatter, or add-trailing-comma can do all this comma insertion automatically. We recommend you use one of those tools instead.
Usage
If you are using flake8 it's as easy as:
pip install flake8-commasNow you can avoid those annoying merge conflicts on dictionary and list diffs.
Errors
Different versions of python require commas in different places. Ignore the errors for languages you don't use in your flake8 config:
| Code | message |
|---|---|
| C812 | missing trailing comma |
| C813 | missing trailing comma in Python 3 |
| C814 | missing trailing comma in Python 2 |
| C815 | missing trailing comma in Python 3.5+ |
| C816 | missing trailing comma in Python 3.6+ |
| C818 | trailing comma on bare tuple prohibited |
| C819 | trailing comma prohibited |
Examples
lookup_table = {
'key1': 'value',
'key2': 'something' # <-- missing a trailing comma
}
json_data = json.dumps({
"key": "value",
}), # <-- incorrect trailing comma. json_data is now a tuple. Likely by accident.