type-hint-checker 0.1.13

Check that all python files have type hints

Type hint checker

Checks that the parameters in functions and methods have type hints. Type hint checker is intended to be used as a pre-commit hook.

def f1(a):
    pass

> git commit 
type_hint_checker.......................................................Failed
    - hook id: type_hint_checker
    - duration: 0.33s
    - exit code: 1
    
    INFO:type_hint_checker:test.py: Missing type hint for parameter a (function f1), line 1
    INFO:type_hint_checker:test.py: Missing return type hint for function f1, line 1

Quick start

1. Install pre-commit hooks https://pre-commit.com/#install

   pip install pre-commit
   

2. Create a .pre-commit-config.yaml or use your existing config file. Add the following lines:

   repos:
   -   repo: https://github.com/PaulinaPacyna/type-hint-checker
       rev: latest
       hooks:
       - id: type_hint_checker
         name: type_hint_checker
         description: Check that all python functions have type hints
         entry: type_hint_checker
         language: python
         verbose: true
         files: ".py$"
         args: [
           #--exit_zero, # always exit with 0 code
           #--exclude_files=tests, #exclude all paths that have the string tests inside
           #--exclude_parameters=^self$, #don't throw warnings about self parameter
        ]
   

3. Install the pre-commit hook

   pre-commit install
   

4. Commit a file

    echo  'def f1(a): pass' > test.py
    git commit test.py -m "Test type_hint_checker pre-commit hook"
   

   The output should be similar to this:

    type_hint_checker.......................................................Failed
    - hook id: type_hint_checker
    - duration: 0.33s
    - exit code: 1
    
    INFO:type_hint_checker:test.py: Missing type hint for parameter a (function f1), line 1
    INFO:type_hint_checker:test.py: Missing return type hint for function f1, line 1
   

Run type hint checker from terminal

0. If you already have it installed in pre-commit hooks:

   pre-commit run type_hint_checker --all-files
   

1. Try the cli version out by running

   pip install type_hint_checker
   

2. Run the tool using

   type_hint_checker <path to file>
   

   or

   python -m type_hint_checker <path to file>
   

Arguments

It is understandable that there are different coding standards. You can customize the behavior of this pre-commit hook by adding the following options to your .pre-commit-config.yaml.

Argument	Usage	Default value	Example values
--exit_zero	If this flag is checked, the program always exits with 0 (success) code. It is strongly advised to use this flag together with verbose: true option in pre-commit options.	Not checked by default.	Either add "--exit_zero" to the args or don't.
--exclude_files	Regex specifying which files should not be checked.	Empty (all files are checked)	"--exclude_files=^test_"
--exclude_parameters	Regex specifying which parameters should not be checked.	^self$	"--exclude_parameters=''" (check all params) "--exclude_parameters='(^self$|logger)'"
--exclude_by_name	Regex specifying names of functions, methods and classes that should not be checked	Empty (all functions, classes and methods are checked).	"--exclude_by_name='^test_'"
--log-level	If set to DEBUG, displays more logs.	INFO	"--log-level=INFO","--log-level=DEBUG"
--ignore_comment	You can change the content of the comment that disables checking a given function or method. By default #no-check excludes the item from being checked. See below for more info.	no-check	"--ignore_comment='hint-no-check'"

If you have troubles setting those values, it may be due to how your system parses special characters in command line options. Add --log-level=DEBUG to you .pre-commit-config.yaml. The log message will show you what values are passed as command line arguments.

DEBUG:type_hint_checker:{'filenames': ['test.py'],
 'exit_zero': False, 
'exclude_files': 'tests/', 
'exclude_parameters': '^self$', 
'exclude_by_name': '', 
'log_level': 'DEBUG', 
'ignore_comment': 'no-check'}

Disable warnings

If you find type_hint_checker too restrictive, you are welcome to adjust its behavior. You can choose to ignore whole files, functions, parameters or single lines

Ignore a path

If you don't want to check a certain file or folder, add the path to the --exclude_files argument. The argument must be a valid regex. To omit checking the directory tests/ and the file setup.py use the following regex in your .pre-commit-config:

args: ["--exclude_files='(tests/|setup.py)'" ]

Ignore a function by name

You can disable checking functions that are named in a certain way. To disable checking all functions that begin with test_ prefix, use:

args: ["--exclude_by_name='^test_" ]

Then, for example this signature won't throw a warning:

def test_filepath_in_log(caplog):
    ...

Ignore a parameter by name

You can disable checking parameters with a regex, e.g. the self parameter

args: [ --exclude_parameters=^self$ ]

With the option shown above, this method signature won't throw any warnings:

class FileMaker:
    def read_file(self) -> str:
        ...

With a comment

In special cases, you can just put #no-check comment next to the function, and the function will be omitted by this pre-commit hook.

def func(a: int, b: int, n): #no-check
    pass

The pre-commit hook will not warn you about the missing type hint for the return and parameter n. You can customize the comment content using --ignore_comment option.

In case of fire

You can always commit without any pre-commit checks using

git commit --no-verify

Pep8 specification about type hints

The default formatting options were set in accordance to PEP8 484

Tests

To run the tests, run

python -m pytest tests/