Issue when userAgent specified and two nested pages are opened

Question

This phantomjs code below is give me the following error:

Assertion failed: (_consumed <= scratch_size), function _hb_coretext_shape, file src/hb-coretext.cc, line 764.
Abort trap: 6

I don't understand what I'm doing wrong.

var querystring = require('querystring')
var webpage = require('webpage')
var main = {}

/* global phantom, $, pass, user, url */

main.loginFormData = function (cb) {
  var page = webpage.create()
  page.settings.userAgent = 'Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/37.0.2062.120 Safari/537.36'
  page.open(url, function (status) {
    page.includeJs('http://ajax.googleapis.com/ajax/libs/jquery/1.8.2/jquery.min.js', function () {
      var form = page.evaluate(function () {
        return {
          'formdata': $('form').serialize(),
          'url': window.location.protocol + '//' + window.location.hostname + $('form').attr('action')
        }
      })
      return cb(form)
    })
  })
}

main.loginLoginForm = function (data, cb) {
  var formdata = querystring.parse(data.formdata)
  formdata.login = user
  formdata.password = pass
  var payload = querystring.stringify(formdata)
  var page = webpage.create()
  page.settings.userAgent = 'Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/37.0.2062.120 Safari/537.36'
  page.open(data.url, 'post', payload, function (status) {
    return cb(status)
  })
}

main.loginFormData(function (data) {
  console.log(JSON.stringify(data, null, 2))
  main.loginLoginForm(data, function (data) {
    console.log(JSON.stringify(data, null, 2))
    phantom.exit()
  })
})

This seems to only occur when calling page.settings.userAgent.

I switched to using promises and the error still occurs.

var Promise = require('bluebird')
var querystring = require('querystring')
var webpage = require('webpage')
var main = {}

var page = webpage.create()
page.settings.userAgent = ua

/* global phantom, $, pass, user, url, ua */

main.loginFormData = function () {
  return new Promise(function (resolve, reject) {
    page.open(url, function (status) {
      if (status !== 'success') return reject(new Error(status))
      page.includeJs('http://ajax.googleapis.com/ajax/libs/jquery/1.8.2/jquery.min.js', function () {
        var data = page.evaluate(function () {
          return {
            'formdata': $('form').serialize(),
            'url': window.location.protocol + '//' + window.location.hostname + $('form').attr('action')
          }
        })
        return resolve(data)
      })
    })
  })
}

main.loginLoginForm = function (data) {
  return new Promise(function (resolve, reject) {
    var formdata = querystring.parse(data.formdata)
    formdata.login = user
    formdata.password = pass
    var payload = querystring.stringify(formdata)
    page.open(data.url, 'post', payload, function (status) {
      if (status !== 'success') return reject(new Error(status))
      return resolve()
    })
  })
}

main.loginFormData(page)
  .then(function (data) {
    // console.log(JSON.stringify(data, null, 2))
    return main.loginLoginForm(page, data)
  })
  .then(function (data) {
    // console.log(JSON.stringify(data, null, 2))
    phantom.exit()
  })
  .catch(function () {
    phantom.exit()
  })

The user agent I'm using is this:

var ua = 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10_10_4) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/44.0.2403.157 Safari/537.36'

Runs successfully when:

• I don't specify page.settings.userAgent
• When I specify a page.settings.userAgent as the default (Mozilla/5.0 (Macintosh; Intel Mac OS X) AppleWebKit/538.1 (KHTML, like Gecko) PhantomJS/2.0.0 Safari/538.1)
• When I specify my custom user agent and I only run the first main.loginFormData.

Runs unexpectedly when:

• I use my custom user agent & run both functions.