1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
|
# flake8-cognitive-complexity
[](https://travis-ci.org/Melevir/flake8-cognitive-complexity)
[](https://codeclimate.com/github/Melevir/flake8-cognitive-complexity/maintainability)
[](https://codeclimate.com/github/Melevir/flake8-cognitive-complexity/test_coverage)
[](https://badge.fury.io/py/flake8-cognitive-complexity)
An extension for flake8 that validates cognitive functions complexity.
Cognitive complexity is analog of cyclomatic complexity, that measure
how difficult to understand piece of code. Introduced by [G. Ann Campbell](https://github.com/ganncamp)
and currently used by SonarSource, CodeClimate and others.
You can find more readings about cognitive complexity in
[cognitive-complexity readme file](https://github.com/Melevir/cognitive_complexity/blob/master/README.md#what-is-cognitive-complexity).
Default complexity is 7, can be configured via `--max-cognitive-complexity` option.
## Installation
```terminal
pip install flake8-cognitive-complexity
```
## Example
```python
def f(a, b):
if a:
for i in range(b):
if b:
return 1
```
Usage:
```terminal
$ flake8 --max-cognitive-complexity=3 test.py
text.py:1:5: CCR001 Cognitive complexity is too high (6 > 3)
```
Tested on Python 3.7.x and flake8 3.7.8.
## Error codes
| Error code | Description |
|:----------:|:----------------------------------------:|
| CCR001 | Cognitive complexity is too high (X > Y) |
|
