WICKET-7024 skip cache update if resource is not found

Author: pedrosans

wicket-core-tests/src/test/java/org/apache/wicket/core/request/resource/PackageResourceReferenceTest.java

@@ -443,6 +443,25 @@ public void decodeStyleFromUrl()
 		assertThat(tester.getLastResponseAsString(), not(containsString("blue")));
 	}
 
+	@Test
+	public void doNotFindNullResourceInTheCache()
+	{
+		IResourceStreamLocator resourceStreamLocator = mock(IResourceStreamLocator.class);
+		when(resourceStreamLocator.locate(scope, "org/apache/wicket/core/request/resource/z.css",
+			"orange", null, null, null, false)).thenReturn(null);
+
+		tester.getApplication().getResourceSettings()
+			.setResourceStreamLocator(new CachingResourceStreamLocator(resourceStreamLocator));
+
+		tester.executeUrl(
+			"wicket/resource/org.apache.wicket.core.request.resource.PackageResourceReferenceTest/z.css?-orange");
+		tester.executeUrl(
+			"wicket/resource/org.apache.wicket.core.request.resource.PackageResourceReferenceTest/z.css?-orange");
+
+		verify(resourceStreamLocator, times(2)).locate(PackageResourceReferenceTest.class,
+			"org/apache/wicket/core/request/resource/z.css", "orange", null, null, null, false);
+	}
+
 	@Test
 	public void doNotFindResourceInTheCache()
 	{

wicket-core/src/main/java/org/apache/wicket/core/request/mapper/BasicResourceReferenceMapper.java

@@ -132,11 +132,17 @@ public IRequestHandler mapRequest(Request request)
 
 			if (scope != null && scope.getPackage() != null)
 			{
-				attributes = PackageResource.sanitize(attributes, scope, name.toString());
+				ResourceReference.UrlAttributes sanitized = PackageResource.sanitize(attributes, scope, name.toString());
+				boolean createIfNotFound = false;
+				if (sanitized != null)
+				{
+					attributes = sanitized;
+					createIfNotFound = true;
+				}
 
 				ResourceReference res = getContext().getResourceReferenceRegistry()
 					.getResourceReference(scope, name.toString(), attributes.getLocale(),
-						attributes.getStyle(), attributes.getVariation(), true, true);
+						attributes.getStyle(), attributes.getVariation(), true, createIfNotFound);
 
 				if (res != null)
 				{

wicket-core/src/main/java/org/apache/wicket/request/resource/PackageResource.java

@@ -871,7 +871,7 @@ public PackageResource readBuffered(boolean readBuffered)
 
 	/**
 	 * @return UrlAttributes with an existent locale/style/variation if a resource is bound to the
-	 * 	scope+name
+	 * 	scope+name, otherwise returns null
 	 */
 	public static ResourceReference.UrlAttributes sanitize(
 		ResourceReference.UrlAttributes urlAttributes, Class<?> scope, String name)
@@ -880,7 +880,7 @@ public static ResourceReference.UrlAttributes sanitize(
 			urlAttributes.getStyle(), urlAttributes.getVariation(), false);
 		if (filesystemMatch == null)
 		{
-			return urlAttributes;
+			return null;
 		}
 		try
 		{