jsx-eslint/eslint-plugin-react

'no-unused-prop-types' breaks when using destructuring in jsx attributes

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#2222 opened on Mar 29, 2019

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bughelp wanted

Description

I was scratching my head over why no-unused-prop-types didn't trigger at all for some of my components, and after some experimentation it turns out it happens whenever I use destructuring in jsx attributes:

const DumbComponent = props => {
  const someObj = { value: 619 };
  return (
    <SomeOtherComp {...someObj} />
  );
};

DumbComponent.propTypes = {
  unused_prop: PropTypes.string // doesn't trigger
};

but

const DumbComponent = props => {
  const someObj = { value: 619 };
  return (
    <SomeOtherComp value={someObj.value} />
  );
};

DumbComponent.propTypes = {
  unused_prop: PropTypes.string // triggers
};

Contributor guide

Tech stack
javascriptreact
Domain
frontendtooling
Issue type
bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
2
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
half day
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
Basic JavaScriptReact propTypesESLint rule structure
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
50
Research direction
Investigate the 'no unused prop types' rule implementation in eslint plugin react. Look for how the rule handles JSX spread attributes versus direct property access. The bug likely lies in the logic that tracks used props; spread attributes may not be correctly parsed as using the properties. Check the rule's source code in the repo, focusing on how it walks the AST for JSX elements and whether destructuring patterns are considered.