Flake8 plugin to validate annotations complexity

Last update: Dec 28, 2022

Overview

flake8-annotations-complexity

An extension for flake8 to report on too complex type annotations.

Complex type annotations often means bad annotations usage, wrong code decomposition or improper data structure choice. They are also hard to read and make code look java-like.

Annotation complexity is maximum annotation nesting level. So List[int] complexity is 2 and Tuple[List[Optional[str]], int] is 4.

Default max annotation complexity is 3 and can be configured via --max-annotations-complexity option.

Installation

pip install flake8-annotations-complexity

Example

Sample file:

# test.py

def foo() -> List[int]:
    return [1]

Usage:

$ flake8 --max-annotations-complexity=1 test.py
test.py:4:14: TAE002 too complex annotation (2 > 1)

Contributing

We would love you to contribute to our project. It's simple:

Create an issue with bug you found or proposal you have. Wait for approve from maintainer.
Create a pull request. Make sure all checks are green.
Fix review comments if any.
Be awesome.

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Comments

0.0.6 release

Hi, thank you for this awesome plugin! Please consider creatng a new release that contains the changes introduced in the PR #14. Otherwise, the latest release on PyPI (0.0.5) raises on Python 3.9, forcing us to resort to install from source repo.

Привет, ребята! Спасибо за отличный плагин к flake8! К сожалению, текущая версия на PyPI (0.0.5) кидает исключение в связке с Python 3.9 - фикс уже есть в основной ветке (PR #14). Прошу выпустить новую версию 0.0.6, содержащую этот фикс - пока приходится устанавливать плагин с мастер-ветки репозитория.
enhancement

opened by hoefling 10
Variable annotations are ignored
Here you only check function annotations: https://github.com/best-doctor/flake8-annotations-complexity/blob/master/flake8_annotations_complexity/ast_helpres.py#L17-L20

However, it is still possible to use really complex variable annotations:

some_value: List[Union[List[str], Dict[str, Dict[str, str]]]] = ...
opened by sobolevn 2

Exception with Literal[""]

An exception is thrown if running flake8 and it finds an empty string in a Literal definition.

To Reproduce I wrote the test for it, so see that: https://github.com/best-doctor/flake8-annotations-complexity/pull/11

Output:

Traceback (most recent call last):
  File "/home/ubuntu/.local/bin/flake8", line 8, in <module>
    sys.exit(main())
  File "/home/ubuntu/.local/lib/python3.8/site-packages/flake8/main/cli.py", line 22, in main
    app.run(argv)
  File "/home/ubuntu/.local/lib/python3.8/site-packages/flake8/main/application.py", line 360, in run
    self._run(argv)
  File "/home/ubuntu/.local/lib/python3.8/site-packages/flake8/main/application.py", line 348, in _run
    self.run_checks()
  File "/home/ubuntu/.local/lib/python3.8/site-packages/flake8/main/application.py", line 262, in run_checks
    self.file_checker_manager.run()
  File "/home/ubuntu/.local/lib/python3.8/site-packages/flake8/checker.py", line 334, in run
    self.run_serial()
  File "/home/ubuntu/.local/lib/python3.8/site-packages/flake8/checker.py", line 318, in run_serial
    checker.run_checks()
  File "/home/ubuntu/.local/lib/python3.8/site-packages/flake8/checker.py", line 598, in run_checks
    self.run_ast_checks()
  File "/home/ubuntu/.local/lib/python3.8/site-packages/flake8/checker.py", line 505, in run_ast_checks
    for (line_number, offset, text, _) in runner:
  File "/home/ubuntu/.local/lib/python3.8/site-packages/flake8_annotations_complexity/checker.py", line 23, in run
    too_difficult_annotations = validate_annotations_in_ast_node(
  File "/home/ubuntu/.local/lib/python3.8/site-packages/flake8_annotations_complexity/ast_helpres.py", line 31, in validate_annotations_in_ast_node
    complexity = get_annotation_complexity(annotation)
  File "/home/ubuntu/.local/lib/python3.8/site-packages/flake8_annotations_complexity/ast_helpres.py", line 12, in get_annotation_complexity
    return 1 + get_annotation_complexity(annotation_node.slice.value)  # type: ignore
  File "/home/ubuntu/.local/lib/python3.8/site-packages/flake8_annotations_complexity/ast_helpres.py", line 8, in get_annotation_complexity
    annotation_node = ast.parse(annotation_node.s).body[0].value  # type: ignore
IndexError: list index out of range

bug

opened by Dreamsorcerer 1

String expression in annotations

According PEP 3107 we can use any expression in annotations. Annotations like this:

def foo() -> 'String Annontation':
    pass

raises syntax error due to impossibility AST parsing this string:

Traceback (most recent call last):
  File "/Users/andrey/.envs/test/bin/flake8", line 8, in <module>
    sys.exit(main())
  File "/Users/andrey/.envs/test/lib/python3.8/site-packages/flake8/main/cli.py", line 18, in main
    app.run(argv)
  File "/Users/andrey/.envs/test/lib/python3.8/site-packages/flake8/main/application.py", line 393, in run
    self._run(argv)
  File "/Users/andrey/.envs/test/lib/python3.8/site-packages/flake8/main/application.py", line 381, in _run
    self.run_checks()
  File "/Users/andrey/.envs/test/lib/python3.8/site-packages/flake8/main/application.py", line 300, in run_checks
    self.file_checker_manager.run()
  File "/Users/andrey/.envs/test/lib/python3.8/site-packages/flake8/checker.py", line 331, in run
    self.run_serial()
  File "/Users/andrey/.envs/test/lib/python3.8/site-packages/flake8/checker.py", line 315, in run_serial
    checker.run_checks()
  File "/Users/andrey/.envs/test/lib/python3.8/site-packages/flake8/checker.py", line 598, in run_checks
    self.run_ast_checks()
  File "/Users/andrey/.envs/test/lib/python3.8/site-packages/flake8/checker.py", line 502, in run_ast_checks
    for (line_number, offset, text, check) in runner:
  File "/Users/andrey/.envs/test/lib/python3.8/site-packages/flake8_annotations_complexity/checker.py", line 23, in run
    too_difficult_annotations = validate_annotations_in_ast_node(
  File "/Users/andrey/.envs/test/lib/python3.8/site-packages/flake8_annotations_complexity/ast_helpres.py", line 28, in validate_annotations_in_ast_node
    complexity = get_annotation_compexity(annotation)
  File "/Users/andrey/.envs/test/lib/python3.8/site-packages/flake8_annotations_complexity/ast_helpres.py", line 7, in get_annotation_compexity
    annotation_node = ast.parse(annotation_node.s).body[0].value  # type: ignore
  File "/Users/andrey/.pyenv/versions/3.8.0/lib/python3.8/ast.py", line 47, in parse
    return compile(source, filename, mode, flags,
  File "<unknown>", line 1
    String Annontation
           ^
SyntaxError: invalid syntax

opened by leksuss 1

fails with AttributeError: 'Slice' object has no attribute 'value'

  File "/Users/ilebedev/.virtualenvs/amy/bin/flake8", line 8, in <module>
    sys.exit(main())
  File "/Users/ilebedev/.virtualenvs/amy/lib/python3.8/site-packages/flake8/main/cli.py", line 18, in main
    app.run(argv)
  File "/Users/ilebedev/.virtualenvs/amy/lib/python3.8/site-packages/flake8/main/application.py", line 393, in run
    self._run(argv)
  File "/Users/ilebedev/.virtualenvs/amy/lib/python3.8/site-packages/flake8/main/application.py", line 381, in _run
    self.run_checks()
  File "/Users/ilebedev/.virtualenvs/amy/lib/python3.8/site-packages/flake8/main/application.py", line 300, in run_checks
    self.file_checker_manager.run()
  File "/Users/ilebedev/.virtualenvs/amy/lib/python3.8/site-packages/flake8/checker.py", line 331, in run
    self.run_serial()
  File "/Users/ilebedev/.virtualenvs/amy/lib/python3.8/site-packages/flake8/checker.py", line 315, in run_serial
    checker.run_checks()
  File "/Users/ilebedev/.virtualenvs/amy/lib/python3.8/site-packages/flake8/checker.py", line 598, in run_checks
    self.run_ast_checks()
  File "/Users/ilebedev/.virtualenvs/amy/lib/python3.8/site-packages/flake8/checker.py", line 502, in run_ast_checks
    for (line_number, offset, text, check) in runner:
  File "/Users/ilebedev/.virtualenvs/amy/lib/python3.8/site-packages/flake8_annotations_complexity/checker.py", line 23, in run
    too_difficult_annotations = validate_annotations_in_ast_node(
  File "/Users/ilebedev/.virtualenvs/amy/lib/python3.8/site-packages/flake8_annotations_complexity/ast_helpres.py", line 28, in validate_annotations_in_ast_node
    complexity = get_annotation_compexity(annotation)
  File "/Users/ilebedev/.virtualenvs/amy/lib/python3.8/site-packages/flake8_annotations_complexity/ast_helpres.py", line 9, in get_annotation_compexity
    return 1 + get_annotation_compexity(annotation_node.slice.value)  # type: ignore
AttributeError: 'Slice' object has no attribute 'value'

Code:


PROJECTS_INFO: Final[List[Tuple[int, str, str, str]]] = [
]

opened by Melevir 1

Empty tuple annotation causes crash

I have some functions that deal with unions where one variant is the empty tuple. Per https://github.com/python/mypy/issues/4211, the way to represent the empty tuple type is typing.Tuple[()]. Using this annotation crashes flake8-annotations-complexity with the following traceback:

Traceback (most recent call last):
  File "/Users/maxchase/.pyenv/versions/structured-data/bin/flake8", line 10, in <module>
    sys.exit(main())
  File "/Users/maxchase/.pyenv/versions/3.7.4/envs/structured-data/lib/python3.7/site-packages/flake8/main/cli.py", line 18, in main
    app.run(argv)
  File "/Users/maxchase/.pyenv/versions/3.7.4/envs/structured-data/lib/python3.7/site-packages/flake8/main/application.py", line 393, in run
    self._run(argv)
  File "/Users/maxchase/.pyenv/versions/3.7.4/envs/structured-data/lib/python3.7/site-packages/flake8/main/application.py", line 381, in _run
    self.run_checks()
  File "/Users/maxchase/.pyenv/versions/3.7.4/envs/structured-data/lib/python3.7/site-packages/flake8/main/application.py", line 300, in run_checks
    self.file_checker_manager.run()
  File "/Users/maxchase/.pyenv/versions/3.7.4/envs/structured-data/lib/python3.7/site-packages/flake8/checker.py", line 331, in run
    self.run_serial()
  File "/Users/maxchase/.pyenv/versions/3.7.4/envs/structured-data/lib/python3.7/site-packages/flake8/checker.py", line 315, in run_serial
    checker.run_checks()
  File "/Users/maxchase/.pyenv/versions/3.7.4/envs/structured-data/lib/python3.7/site-packages/flake8/checker.py", line 598, in run_checks
    self.run_ast_checks()
  File "/Users/maxchase/.pyenv/versions/3.7.4/envs/structured-data/lib/python3.7/site-packages/flake8/checker.py", line 502, in run_ast_checks
    for (line_number, offset, text, check) in runner:
  File "/Users/maxchase/.pyenv/versions/3.7.4/envs/structured-data/lib/python3.7/site-packages/flake8_annotations_complexity/checker.py", line 25, in run
    self.max_annotations_complexity,
  File "/Users/maxchase/.pyenv/versions/3.7.4/envs/structured-data/lib/python3.7/site-packages/flake8_annotations_complexity/ast_helpres.py", line 28, in validate_annotations_in_ast_node
    complexity = get_annotation_compexity(annotation)
  File "/Users/maxchase/.pyenv/versions/3.7.4/envs/structured-data/lib/python3.7/site-packages/flake8_annotations_complexity/ast_helpres.py", line 9, in get_annotation_compexity
    return 1 + get_annotation_compexity(annotation_node.slice.value)  # type: ignore
  File "/Users/maxchase/.pyenv/versions/3.7.4/envs/structured-data/lib/python3.7/site-packages/flake8_annotations_complexity/ast_helpres.py", line 11, in get_annotation_compexity
    return max(get_annotation_compexity(n) for n in annotation_node.elts)
  File "/Users/maxchase/.pyenv/versions/3.7.4/envs/structured-data/lib/python3.7/site-packages/flake8_annotations_complexity/ast_helpres.py", line 11, in <genexpr>
    return max(get_annotation_compexity(n) for n in annotation_node.elts)
  File "/Users/maxchase/.pyenv/versions/3.7.4/envs/structured-data/lib/python3.7/site-packages/flake8_annotations_complexity/ast_helpres.py", line 9, in get_annotation_compexity
    return 1 + get_annotation_compexity(annotation_node.slice.value)  # type: ignore
  File "/Users/maxchase/.pyenv/versions/3.7.4/envs/structured-data/lib/python3.7/site-packages/flake8_annotations_complexity/ast_helpres.py", line 11, in get_annotation_compexity
    return max(get_annotation_compexity(n) for n in annotation_node.elts)
ValueError: max() arg is an empty sequence

I can put in a PR for this.

opened by mwchase 1

`if annotation_len > 7:`

annotation_len compares with constant 7 and not max_annotation_len :( But max_annotation_len is used in error message formatting.

https://github.com/best-doctor/flake8-annotations-complexity/blob/master/flake8_annotations_complexity/ast_helpers.py#L65
bug

opened by abcdenis 0
Add max complexity configuration from file

Is your feature request related to a problem? Please describe. The only documented method for configuring the max complexity is a command line switch. It is difficult to enforce a common standard in a shared codebase, or ensure CI is using the correct settings this way.

Describe the solution you'd like A configuration option I can put in pyproject.toml to ensure the setting I desire is respected for all callers of flake8 in my repo.

Describe alternatives you've considered Do nothing. Easiest, but it doesn't address the issue.

Additional context N/A
enhancement

opened by rpdelaney 0