Cannot find elements when XPath expression is null

Bug Report
,
16

Additional comment:

When I ran the Test Case TC1 of https://github.com/kazurayam/Cannot_find_elements_when_XPath_expression_is_null project, I got the following message in the Console:

2018-12-22 20:28:17.159 ERROR c.k.katalon.core.main.TestCaseExecutor   - ❌ Test Cases/TC1 FAILED.
Reason:
com.kms.katalon.core.exception.StepFailedException: Unable to verify object 'Object Repository/Page_AngularJS Hub  Text Inputs/iframe_Example_exampleIFrame' is present (Root cause: java.lang.IllegalArgumentException: Cannot find elements when the XPath expression is null.)
	at com.kms.katalon.core.keyword.internal.KeywordMain.stepFailed(KeywordMain.groovy:36)
	at com.kms.katalon.core.webui.keyword.internal.WebUIKeywordMain.stepFailed(WebUIKeywordMain.groovy:65)
	at com.kms.katalon.core.webui.keyword.internal.WebUIKeywordMain.runKeyword(WebUIKeywordMain.groovy:27)
...

This message does not tell me where the IllegalArgumentException was raised, by which class, by which method in which line. I wanted to see the StackTrace of the IllegalArgumentException. I wondered why the Stack Trace is not printed.

I read the source of VerifyElementPresentKeyword and other related classes.

I would like to propose to Katalon Team to modify the com.kms.katalon.core.webui.keyword.internal.WebUIKeywordMain class.

public class WebUIKeywordMain {

    private static final String TIMED_OUT_WAITING_FOR_PAGE_LOAD = "Timed out waiting for page load."

    @CompileStatic
    public static runKeyword(Closure closure, FailureHandling flowControl, boolean takeScreenShot, String errorMessage) {
        try {
            return closure.call();
        } catch (Throwable e) {
            if (isPageLoadTimeoutException(e) && DriverFactory.isEnablePageLoadTimeout() && DriverFactory.isIgnorePageLoadTimeoutException()) {
                stepFailed(errorMessage, FailureHandling.OPTIONAL, ExceptionsUtil.getMessageForThrowable(e), takeScreenShot);
                return;
            }

            // kazurayam wants to insert a line here
            e.printStackTrace()

            stepFailed(errorMessage, flowControl, ExceptionsUtil.getMessageForThrowable(e), takeScreenShot);
        }
    }