InvalidSelectorException caused by TypeError: q is null with FF 37.0.1 and Selenium 2.45.0

[Veranika Ivanova]

Hi all,

I send  http call in browser to log out from application and then xml response opens in browser. I need to check tag value in this response.

Page source code is:

<?xml version="1.0" encoding="UTF-8"?>

<hash>

  <result type="boolean">true</result>

</hash>

I search an element by xPath //*[text()='true']

When I launch this test in FF 34.0 with selenium 2.44.0, everything is OK
But when I try in FF 37.0 with selenium 2.45.0 I'm getting the following error:

07:22:47.776 INFO - Executing: [find element: By.xpath: //*[text()='true']])

07:22:47.950 WARN - Exception thrown

org.openqa.selenium.InvalidSelectorException: The given selector //*[text()='true'] is either invalid or does not result in

a WebElement. The following error occurred:

InvalidSelectorError: Unable to locate an element with the xpath expression //*[text()='true'] because of the following err

r:

TypeError: q is null

Command duration or timeout: 7 milliseconds

For documentation on this error, please visit: http://seleniumhq.org/exceptions/invalid_selector_exception.html

Build info: version: '2.45.0', revision: '5017cb8', time: '2015-02-26 23:59:50'

*** Element info: {Using=xpath, value=//*[text()='true']}

Session ID: 21afcdd7-ffae-453d-8463-3bec9da0532c

Driver info: org.openqa.selenium.firefox.FirefoxDriver

Capabilities [{platform=WINDOWS, acceptSslCerts=true, javascriptEnabled=true, cssSelectorsEnabled=true, databaseEnabled=tru

, browserName=firefox, handlesAlerts=true, nativeEvents=false, webStorageEnabled=true, rotatable=false, locationContextEnab

ed=true, applicationCacheEnabled=true, takesScreenshot=true, version=37.0.1}]

        at sun.reflect.GeneratedConstructorAccessor30.newInstance(Unknown Source)

        at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)

        at java.lang.reflect.Constructor.newInstance(Unknown Source)

        at org.openqa.selenium.remote.ErrorHandler.createThrowable(ErrorHandler.java:204)

        at org.openqa.selenium.remote.ErrorHandler.throwIfResponseFailed(ErrorHandler.java:156)

        at org.openqa.selenium.remote.RemoteWebDriver.execute(RemoteWebDriver.java:599)

        at org.openqa.selenium.remote.RemoteWebDriver.findElement(RemoteWebDriver.java:352)

        at org.openqa.selenium.remote.RemoteWebDriver.findElementByXPath(RemoteWebDriver.java:449)

        at org.openqa.selenium.By$ByXPath.findElement(By.java:357)

        at org.openqa.selenium.remote.RemoteWebDriver.findElement(RemoteWebDriver.java:344)

        at sun.reflect.GeneratedMethodAccessor12.invoke(Unknown Source)

        at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)

        at java.lang.reflect.Method.invoke(Unknown Source)

        at org.openqa.selenium.support.events.EventFiringWebDriver$2.invoke(EventFiringWebDriver.java:101)

        at com.sun.proxy.$Proxy1.findElement(Unknown Source)

        at org.openqa.selenium.support.events.EventFiringWebDriver.findElement(EventFiringWebDriver.java:184)

        at org.openqa.selenium.remote.server.handler.FindElement.call(FindElement.java:47)

        at org.openqa.selenium.remote.server.handler.FindElement.call(FindElement.java:1)

        at java.util.concurrent.FutureTask.run(Unknown Source)

        at org.openqa.selenium.remote.server.DefaultSession$1.run(DefaultSession.java:168)

        at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)

        at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)

        at java.lang.Thread.run(Unknown Source)

Caused by: org.openqa.selenium.InvalidSelectorException: The given selector //*[text()='true'] is either invalid or does no

 result in a WebElement. The following error occurred:

InvalidSelectorError: Unable to locate an element with the xpath expression //*[text()='true'] because of the following err

r:

TypeError: q is null

For documentation on this error, please visit: http://seleniumhq.org/exceptions/invalid_selector_exception.html

I checked this xPath in Firebug and it works. I aslo tried to use //*, //result[text()='true'] and I always get such error.

Have you any ideas what it could be caused by? 
Is this selenium issue or my xPath is really invalid?

Thank you in advance,
Veranika

[Musaffir Lp]

Looks liks it an issue with 2.45.0

can you try with selenium 2.46 and update ..

[Vladyslav Lopatynskyi]

Try to set Implicit wait for your webDriver instance. 

It looks like you don't have it at all.  (Command duration or timeout: 7 milliseconds)

driver.manage().timeouts().implicitlyWait(10, TimeUnit.SECONDS);

Seems selenium tried to reach element before it has been appeared