[WICKET-6332] NullPointerException in PageParameters#equals()

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 7.6.0, 8.0.0-M4
• Fix Version/s: 7.7.0, 8.0.0-M9
• Component/s: wicket
• Assignee: Martin Tzvetanov Grigorov
• Reporter: Alexey Grigorovitch
• Created: 06/Mar/17 05:54
• Updated: 06/Feb/18 12:51
• Resolved: 06/Mar/17 08:05

Description

Comparing an instance of PageParameters with some parameters set to an empty PageParameters instance results in a NullPointerException.

This bug was introduced by WICKET-6283 where collection equality was replaced by CollectionUtils.isEmptyCollection(). The latter API expects both arguments to be non-null, while the former accepts nulls.

Test case:

	/**
         * namedParameters equality should handle null namedParameters instance.
	 */
	@Test
	public void equalityWithEmptyParameters()
	{
		PageParameters p1 = new PageParameters()
				.add("a", "b");

		PageParameters p2 = new PageParameters();

		assertThat(p1, is(not(equalTo(p2))));
	}

Output:

java.lang.NullPointerException
	at org.apache.commons.collections4.CollectionUtils.isEqualCollection(CollectionUtils.java:515)
	at org.apache.wicket.request.mapper.parameter.PageParameters.equals(PageParameters.java:470)
	at org.hamcrest.core.IsEqual.areEqual(IsEqual.java:40)
	at org.hamcrest.core.IsEqual.matches(IsEqual.java:23)
	at org.hamcrest.core.IsNot.matches(IsNot.java:22)
	at org.hamcrest.core.Is.matches(Is.java:26)
	at org.hamcrest.MatcherAssert.assertThat(MatcherAssert.java:10)
	at org.junit.Assert.assertThat(Assert.java:956)
	at org.junit.Assert.assertThat(Assert.java:923)
	at org.apache.wicket.request.mapper.parameter.PageParametersTest.equalityWithEmptyParameters(PageParametersTest.java:328)

Issue Links

• relates to: WICKET-6283 Page parameter equality should not depend on named parameters order