Cannot read property length of undefined in jsx-handler-names

[lencioni]

Hi! Using 3.11.1 I just tried enabling jsx-handler-names with the following configuration:

'react/jsx-handler-names': [2, {
  'eventHandlerPrefix': 'handle',
  'eventHandlerPropPrefix': 'on',
}]

And I got the following error:

/path/to/node_modules/eslint-plugin-react/lib/rules/jsx-handler-names.js:32
    if (propertyName.length) {
                    ^

TypeError: Cannot read property 'length' of undefined
    at rebuildPropValue (/path/to/node_modules/eslint-plugin-react/lib/rules/jsx-handler-names.js:32:21)
    at EventEmitter.JSXAttribute (/path/to/node_modules/eslint-plugin-react/lib/rules/jsx-handler-names.js:50:23)
    at emitOne (events.js:82:20)
    at EventEmitter.emit (events.js:169:7)
    at NodeEventGenerator.enterNode (/path/to/node_modules/eslint/lib/util/node-event-generator.js:42:22)
    at CommentEventGenerator.enterNode (/path/to/node_modules/eslint/lib/util/comment-event-generator.js:98:23)
    at Controller.controller.traverse.enter (/path/to/node_modules/eslint/lib/eslint.js:767:36)
    at Controller.__execute (/path/to/node_modules/estraverse/estraverse.js:397:31)
    at Controller.traverse (/path/to/node_modules/estraverse/estraverse.js:495:28)
    at EventEmitter.module.exports.api.verify (/path/to/node_modules/eslint/lib/eslint.js:764:24)

I'm not really sure what the JS looks like that it is blowing up on, but I figured I'd post this here to start with.

[lencioni]

Alright, here's a repro case. It seems to happen when a prop is a property of an item of an array:

const Test = React.createClass({
  render() {
    return (
      <Something
        myProp={arr[0].prop}
      />
    );
  }
});

module.exports = Test;