reactive-python / reactpy-flake8

Flake8 plugin for enforcing the rules of hooks for IDOM

reactpy-flake8

A Flake8 plugin that enforces the "rules of hooks" for ReactPy.

The implementation is based on React's own ESLint plugin for hooks.

Install

pip install reactpy-flake8

Developer Installation

pip install -r requirements.txt
pip install -e .

Run the tests

nox -s test

Errors

Code	Message
RPY100	Hook is defined as a closure
RPY101	Hook was used outside component or hook definition
RPY102	Hook was used inside a conditional or loop statement
RPY103	Hook was used after an early return
RPY200	A hook's dependency is not destructured - dependencies should be refered to directly, not via an attribute or key of an object
RPY201	Hook dependency args should be a literal list, tuple or None
RPY202	Hook dependency is not specified

Options

All options my be used as CLI flags where _ characters are replaced with -. For example, exhaustive_hook_deps would become --exhaustive-hook-deps.

Option	Type	Default	Description
exhaustive_hook_deps	Boolean	False	Enable REACTPY2** errors (recommended)
component_decorator_pattern	Regex	^(component|[\w\.]+\.component)$	The pattern which should match the component decorators. Useful if you import the @component decorator under an alias.
hook_function_pattern	Regex	^_*use_\w+$	The pattern which should match the name of hook functions. Best used if you have existing functions with use_* names that are not hooks.

reactpy-flake8's Issues

No Error For Early Returns

Right now, we don't produce an error for early returns:

@component
def example():
    if True:
        return None
    use_state()  # should produce error

There is no technical reason that this couldn't be supported however, as per this comment:

...semantics get very confusing. What would happen to state below? Would it be reset or preserved? What about effects? Would they be cleaned up (like on unmount) or would they run normally? If you think about it you’ll find cases that are very confusing regardless of the behavior you pick. Therefore, we disallow this pattern altogether. Put early return after calls to Hooks.

We do not check for usages of match statements

The new match statement in Python 3.10 (a conditional) isn't covered by the linter right now.

Release `reactpy-flake8` package

This package is currently unreleased, despite having been moved under the reactpy umbrella.

Warn users if using abnormally long tree depth

If someone has an idom.html tree that spans >= 5 levels deep, we should probably generate a warning that they should splitting it apart into components.

For example

html.div(
    html.div(
        html.div(
            html.div(
                html.div(
                    html.div("Hello World"),
                ),
            ),
        ),
    ),
)

ROH101 should only happen if the hook is called

This causes it to fail:

# just trying to create alias to the function
use_scope = some_module.use_scope

Default `exhaustive_hook_deps` to `True`

If the exhaustive_hook_deps is recommended to be used, it's best to set it to default.

Also the readme doesn't mention how/if reactpy-flake8 settings can be changed from the .flake8 configuration file.