Cannot read property 'length' of undefined in lib/rules/prop-types.js line 51

[lencioni]

After upgrading from 1.3.0 to 1.4.1, I am getting this error message:

/path/to/project/node_modules/eslint-plugin-react/lib/rules/prop-types.js:51
        for (var i = 0, j = property.value.properties.length; i < j; i++) {
                                                     ^
TypeError: Cannot read property 'length' of undefined
    at /path/to/project/node_modules/eslint-plugin-react/lib/rules/prop-types.js:51:54
    at Array.forEach (native)
    at EventEmitter.ObjectExpression (/path/to/project/node_modules/eslint-plugin-react/lib/rules/prop-types.js:46:23)
    at EventEmitter.emit (events.js:117:20)
    at Controller.controller.traverse.enter (/path/to/project/node_modules/eslint/lib/eslint.js:683:25)
    at Controller.__execute (/path/to/project/node_modules/eslint/node_modules/estraverse/estraverse.js:397:31)
    at Controller.traverse (/path/to/project/node_modules/eslint/node_modules/estraverse/estraverse.js:495:28)
    at EventEmitter.module.exports.api.verify (/path/to/project/node_modules/eslint/lib/eslint.js:676:24)
    at processFile (/path/to/project/node_modules/eslint/lib/cli-engine.js:172:23)
    at /path/to/project/node_modules/eslint/lib/cli-engine.js:271:26
    at /path/to/project/node_modules/eslint/lib/util/traverse.js:61:17

[yannickcr]

I'll have a look at it. Can you share the code that trigger this error?

[lencioni]

I'll try to whittle it down. Might take a bit.

[lencioni]

Ah, it looks like it happens when I am defining an object outside of the component to hold the propTypes, and then assigning it to that variable.

Something like:

const myPropTypes = {
  ...
};

const MyComponent = React.createClass({
  propTypes: myPropTypes,

  ...
});

[yannickcr]

Ok, I see. I can fix the crash but I am not sure how to check propTypes definition in this case. I need to figure that out.

[lencioni]

Even if I try disabling this rule for the affected file via /* eslint-disable react/prop-types */ or even /* eslint-disable */, I still see the crash. If I disable it via .eslintignore, the crash is avoided.

I've refactored my code so I don't need this anymore, but it would be nice to be able to at least disable this rule on a per-file basis using the comments.

[josiasds]

The same error is happening here: https://github.com/shakacode/react-webpack-rails-tutorial/blob/cd35765c0a0d1a755c30944b4879bc12ca8e8163/client/app/stores/commentsStore.js#L8

This fixes the error, but I don't know exactly why. Any ideas?