Data binding with java.util.Optional: traversal of nested paths, detection of empty holders [SPR-12241]

[spring-projects-issues]

Federico Donnarumma opened SPR-12241 and commented

Hi, I have this case, when validating with JSR-303.

I Have an object which contains an Optional, when SpringValidatorAdapter cycles through properties to show something of the style

"you entered 0 but field nights should be higher than 0"

BeanWrapper can't access the object inside the Optional and I get this message:

java.lang.IllegalStateException: JSR-303 validated property 'earlyCancellation.deadlines[0].penalty.nights' does not have a corresponding accessor for Spring data binding - check your DataBinder's configuration (bean property versus direct field access)
	at org.springframework.validation.beanvalidation.SpringValidatorAdapter.processConstraintViolations(SpringValidatorAdapter.java:158) ~[spring-context-4.1.0.RELEASE.jar:4.1.0.RELEASE]
	at org.springframework.validation.beanvalidation.SpringValidatorAdapter.validate(SpringValidatorAdapter.java:107) ~[spring-context-4.1.0.RELEASE.jar:4.1.0.RELEASE]
	at org.springframework.validation.DataBinder.validate(DataBinder.java:760) ~[spring-context-4.1.0.RELEASE.jar:4.1.0.RELEASE]
	at org.springframework.web.servlet.mvc.method.annotation.RequestResponseBodyMethodProcessor.validate(RequestResponseBodyMethodProcessor.java:123) ~[spring-webmvc-4.1.0.RELEASE.jar:4.1.0.RELEASE]
	at org.springframework.web.servlet.mvc.method.annotation.RequestResponseBodyMethodProcessor.resolveArgument(RequestResponseBodyMethodProcessor.java:109) ~[spring-webmvc-4.1.0.RELEASE.jar:4.1.0.RELEASE]
	at org.springframework.web.method.support.HandlerMethodArgumentResolverComposite.resolveArgument(HandlerMethodArgumentResolverComposite.java:79) ~[spring-web-4.1.0.RELEASE.jar:4.1.0.RELEASE]
	at org.springframework.web.method.support.InvocableHandlerMethod.getMethodArgumentValues(InvocableHandlerMethod.java:157) ~[spring-web-4.1.0.RELEASE.jar:4.1.0.RELEASE]
	at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:124) ~[spring-web-4.1.0.RELEASE.jar:4.1.0.RELEASE]
	at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:104) ~[spring-webmvc-4.1.0.RELEASE.jar:4.1.0.RELEASE]
	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandleMethod(RequestMappingHandlerAdapter.java:781) ~[spring-webmvc-4.1.0.RELEASE.jar:4.1.0.RELEASE]
	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:721) ~[spring-webmvc-4.1.0.RELEASE.jar:4.1.0.RELEASE]
	at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:83) ~[spring-webmvc-4.1.0.RELEASE.jar:4.1.0.RELEASE]
	at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:943) ~[spring-webmvc-4.1.0.RELEASE.jar:4.1.0.RELEASE]
	at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:877) ~[spring-webmvc-4.1.0.RELEASE.jar:4.1.0.RELEASE]
	at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:961) [spring-webmvc-4.1.0.RELEASE.jar:4.1.0.RELEASE]
	at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:863) [spring-webmvc-4.1.0.RELEASE.jar:4.1.0.RELEASE]
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:707) ~[javax.servlet-api-3.1.0.jar:3.1.0]
	at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:837) [spring-webmvc-4.1.0.RELEASE.jar:4.1.0.RELEASE]
	at org.springframework.test.web.servlet.TestDispatcherServlet.service(TestDispatcherServlet.java:62) [spring-test-4.1.0.RELEASE.jar:4.1.0.RELEASE]
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:790) ~[javax.servlet-api-3.1.0.jar:3.1.0]
	at org.springframework.mock.web.MockFilterChain$ServletFilterProxy.doFilter(MockFilterChain.java:170) [spring-test-4.1.0.RELEASE.jar:4.1.0.RELEASE]
	at org.springframework.mock.web.MockFilterChain.doFilter(MockFilterChain.java:137) [spring-test-4.1.0.RELEASE.jar:4.1.0.RELEASE]
	at org.springframework.test.web.servlet.MockMvc.perform(MockMvc.java:145) [spring-test-4.1.0.RELEASE.jar:4.1.0.RELEASE]
	at com.despegar.bookedia.cancelpolicy.CustomCancelPolicyControllerTest.post_zeroEarlyCancellationNights_okStatus(CustomCancelPolicyControllerTest.java:357) [test-classes/:na]
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_05]
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_05]
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_05]
	at java.lang.reflect.Method.invoke(Method.java:483) ~[na:1.8.0_05]
	at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:47) [junit-4.11.jar:na]
	at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12) [junit-4.11.jar:na]
	at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:44) [junit-4.11.jar:na]
	at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17) [junit-4.11.jar:na]
	at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:26) [junit-4.11.jar:na]
	at org.springframework.test.context.junit4.statements.RunBeforeTestMethodCallbacks.evaluate(RunBeforeTestMethodCallbacks.java:72) [spring-test-4.1.0.RELEASE.jar:4.1.0.RELEASE]
	at org.springframework.test.context.junit4.statements.RunAfterTestMethodCallbacks.evaluate(RunAfterTestMethodCallbacks.java:81) [spring-test-4.1.0.RELEASE.jar:4.1.0.RELEASE]
	at org.springframework.test.context.junit4.statements.SpringRepeat.evaluate(SpringRepeat.java:72) [spring-test-4.1.0.RELEASE.jar:4.1.0.RELEASE]
	at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:271) [junit-4.11.jar:na]
	at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:216) [spring-test-4.1.0.RELEASE.jar:4.1.0.RELEASE]
	at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:82) [spring-test-4.1.0.RELEASE.jar:4.1.0.RELEASE]
	at org.junit.runners.ParentRunner$3.run(ParentRunner.java:238) [junit-4.11.jar:na]
	at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:63) [junit-4.11.jar:na]
	at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:236) [junit-4.11.jar:na]
	at org.junit.runners.ParentRunner.access$000(ParentRunner.java:53) [junit-4.11.jar:na]
	at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:229) [junit-4.11.jar:na]
	at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:60) [spring-test-4.1.0.RELEASE.jar:4.1.0.RELEASE]
	at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:67) [spring-test-4.1.0.RELEASE.jar:4.1.0.RELEASE]
	at org.junit.runners.ParentRunner.run(ParentRunner.java:309) [junit-4.11.jar:na]
	at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:162) [spring-test-4.1.0.RELEASE.jar:4.1.0.RELEASE]
	at org.junit.runner.JUnitCore.run(JUnitCore.java:160) [junit-4.11.jar:na]
	at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:74) [junit-rt.jar:na]
	at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:211) [junit-rt.jar:na]
	at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:67) [junit-rt.jar:na]
Caused by: org.springframework.beans.NotReadablePropertyException: Invalid property 'earlyCancellation.deadlines[0]' of bean class [com.despegar.bookedia.cancelpolicy.CancelPolicyDTO]: Bean property 'earlyCancellation.deadlines[0]' is not readable or has an invalid getter method: Does the return type of the getter match the parameter type of the setter?
	at org.springframework.beans.BeanWrapperImpl.getPropertyValue(BeanWrapperImpl.java:705) ~[spring-beans-4.1.0.RELEASE.jar:4.1.0.RELEASE]
	at org.springframework.beans.BeanWrapperImpl.getNestedBeanWrapper(BeanWrapperImpl.java:551) ~[spring-beans-4.1.0.RELEASE.jar:4.1.0.RELEASE]
	at org.springframework.beans.BeanWrapperImpl.getBeanWrapperForPropertyPath(BeanWrapperImpl.java:528) ~[spring-beans-4.1.0.RELEASE.jar:4.1.0.RELEASE]
	at org.springframework.beans.BeanWrapperImpl.getBeanWrapperForPropertyPath(BeanWrapperImpl.java:529) ~[spring-beans-4.1.0.RELEASE.jar:4.1.0.RELEASE]
	at org.springframework.beans.BeanWrapperImpl.getPropertyValue(BeanWrapperImpl.java:694) ~[spring-beans-4.1.0.RELEASE.jar:4.1.0.RELEASE]
	at org.springframework.validation.AbstractPropertyBindingResult.getActualFieldValue(AbstractPropertyBindingResult.java:99) ~[spring-context-4.1.0.RELEASE.jar:4.1.0.RELEASE]
	at org.springframework.validation.AbstractBindingResult.getRawFieldValue(AbstractBindingResult.java:283) ~[spring-context-4.1.0.RELEASE.jar:4.1.0.RELEASE]
	at org.springframework.validation.beanvalidation.SpringValidatorAdapter.processConstraintViolations(SpringValidatorAdapter.java:143) ~[spring-context-4.1.0.RELEASE.jar:4.1.0.RELEASE]
	... 51 common frames omitted

---

Affects: 4.1 GA

Issue Links:

• Support for java.util.Optional with @Inject (a la @Autowired's required=false) [SPR-11833] #16452 Support for java.util.Optional with @Inject (a la @Autowired's required=false)
• Unable to define empty java.util.Optional bean in spring xml [SPR-14121] #18693 Unable to define empty java.util.Optional bean in spring xml

Referenced from: commits cfc821d, 0934751

[spring-projects-issues]

Federico Donnarumma commented

Do you have any workaround to fix this in the meantime?

[spring-projects-issues]

Juergen Hoeller commented

Hibernate Validator itself doesn't seem to support Optional yet... Could you show what your code looks like, i.e. what exactly is declared as Optional? I suppose just a getter, not the field?

Juergen

[spring-projects-issues]

Federico Donnarumma commented

Hi Jurgen, as soon as I get back to the office I'll send you te code, but. I can say that getter and field are both Optional.

[spring-projects-issues]

Juergen Hoeller commented

Fixed for Spring Framework 4.1.1 now, with BeanWrapper supporting the traversal of nested paths with Java 8 Optional declarations. Note that this only works for Spring data binding, i.e. getter methods for value access. We can't do anything about Hibernate Validator's lack of support for Optional fields; this is planned for Hibernate Validator 5.2 on their side.

Juergen

[spring-projects-issues]

Juergen Hoeller commented

Federico, please give the upcoming 4.1.1 snapshot a try and let me know whether the degree of Optional data binding support in there works for you. If for some reason the Optional field declaration works for your use of Hibernate Validator as well, then all the power to you!

Juergen

[spring-projects-issues]

Federico Donnarumma commented

Thanks Juergen, I'll give it a try ASAP, in the meantime I'll add a bug regarding TransactionContextHolder and TransactionalTestExecutionListener

[spring-projects-issues]

Federico Donnarumma commented

Thanks Juergen, now it's working as expected. You are the man :)

[spring-projects-issues]

Federico Donnarumma commented

Ok, not working for all cases, regression failed.

Seems to fail when you use Optional.emtpy

java.lang.IllegalArgumentException: Optional value must be present
	at org.springframework.util.Assert.isTrue(Assert.java:65) ~[spring-core-4.1.1.BUILD-20140924.155845-31.jar:4.1.1.BUILD-SNAPSHOT]
	at org.springframework.beans.BeanWrapperImpl$OptionalUnwrapper.unwrap(BeanWrapperImpl.java:1214) ~[spring-beans-4.1.1.BUILD-20140924.155845-31.jar:4.1.1.BUILD-SNAPSHOT]

[spring-projects-issues]

Federico Donnarumma commented

Not working for Optional.empty

[spring-projects-issues]

Juergen Hoeller commented

What are the next few lines in the stacktrace there?

We can't bind against an empty Optional object, so we're treating it like a null value... rejecting it where a null value would get rejected as well. Are we getting that wrong somewhere?

Juergen

[spring-projects-issues]

Federico Donnarumma commented

The assert seems to be wrong. An empty optional is still an Optional

Optional<?> optional = (Optional<?>) optionalObject;
Assert.isTrue(optional.isPresent(), "Optional value must be present");

Full stack.

java.lang.IllegalArgumentException: Optional value must be present
	at org.springframework.util.Assert.isTrue(Assert.java:65) ~[spring-core-4.1.1.BUILD-20140924.155845-31.jar:4.1.1.BUILD-SNAPSHOT]
	at org.springframework.beans.BeanWrapperImpl$OptionalUnwrapper.unwrap(BeanWrapperImpl.java:1214) ~[spring-beans-4.1.1.BUILD-20140924.155845-31.jar:4.1.1.BUILD-SNAPSHOT]
	at org.springframework.beans.BeanWrapperImpl.setWrappedInstance(BeanWrapperImpl.java:228) ~[spring-beans-4.1.1.BUILD-20140924.155845-31.jar:4.1.1.BUILD-SNAPSHOT]
	at org.springframework.beans.BeanWrapperImpl.setWrappedInstance(BeanWrapperImpl.java:215) ~[spring-beans-4.1.1.BUILD-20140924.155845-31.jar:4.1.1.BUILD-SNAPSHOT]
	at org.springframework.beans.BeanWrapperImpl.<init>(BeanWrapperImpl.java:164) ~[spring-beans-4.1.1.BUILD-20140924.155845-31.jar:4.1.1.BUILD-SNAPSHOT]
	at org.springframework.beans.PropertyAccessorFactory.forBeanPropertyAccess(PropertyAccessorFactory.java:37) ~[spring-beans-4.1.1.BUILD-20140924.155845-31.jar:4.1.1.BUILD-SNAPSHOT]
	at org.springframework.validation.BeanPropertyBindingResult.createBeanWrapper(BeanPropertyBindingResult.java:106) ~[spring-context-4.1.1.BUILD-20140924.155845-31.jar:4.1.1.BUILD-SNAPSHOT]
	at org.springframework.validation.BeanPropertyBindingResult.getPropertyAccessor(BeanPropertyBindingResult.java:92) ~[spring-context-4.1.1.BUILD-20140924.155845-31.jar:4.1.1.BUILD-SNAPSHOT]
	at org.springframework.validation.AbstractPropertyBindingResult.initConversion(AbstractPropertyBindingResult.java:62) ~[spring-context-4.1.1.BUILD-20140924.155845-31.jar:4.1.1.BUILD-SNAPSHOT]
	at org.springframework.validation.DataBinder.initBeanPropertyAccess(DataBinder.java:237) ~[spring-context-4.1.1.BUILD-20140924.155845-31.jar:4.1.1.BUILD-SNAPSHOT]
	at org.springframework.validation.DataBinder.getInternalBindingResult(DataBinder.java:261) ~[spring-context-4.1.1.BUILD-20140924.155845-31.jar:4.1.1.BUILD-SNAPSHOT]
	at org.springframework.validation.DataBinder.getPropertyAccessor(DataBinder.java:270) ~[spring-context-4.1.1.BUILD-20140924.155845-31.jar:4.1.1.BUILD-SNAPSHOT]
	at org.springframework.validation.DataBinder.applyPropertyValues(DataBinder.java:728) ~[spring-context-4.1.1.BUILD-20140924.155845-31.jar:4.1.1.BUILD-SNAPSHOT]
	at org.springframework.validation.DataBinder.doBind(DataBinder.java:624) ~[spring-context-4.1.1.BUILD-20140924.155845-31.jar:4.1.1.BUILD-SNAPSHOT]
	at org.springframework.web.bind.WebDataBinder.doBind(WebDataBinder.java:189) ~[spring-web-4.1.1.BUILD-20140924.155845-31.jar:4.1.1.BUILD-SNAPSHOT]
	at org.springframework.web.bind.ServletRequestDataBinder.bind(ServletRequestDataBinder.java:106) ~[spring-web-4.1.1.BUILD-20140924.155845-31.jar:4.1.1.BUILD-SNAPSHOT]
	at org.springframework.web.servlet.mvc.method.annotation.ServletModelAttributeMethodProcessor.bindRequestParameters(ServletModelAttributeMethodProcessor.java:153) ~[spring-webmvc-4.1.1.BUILD-20140924.155845-31.jar:4.1.1.BUILD-SNAPSHOT]
	at org.springframework.web.method.annotation.ModelAttributeMethodProcessor.resolveArgument(ModelAttributeMethodProcessor.java:108) ~[spring-web-4.1.1.BUILD-20140924.155845-31.jar:4.1.1.BUILD-SNAPSHOT]
	at org.springframework.web.method.support.HandlerMethodArgumentResolverComposite.resolveArgument(HandlerMethodArgumentResolverComposite.java:79) ~[spring-web-4.1.1.BUILD-20140924.155845-31.jar:4.1.1.BUILD-SNAPSHOT]
	at org.springframework.web.method.support.InvocableHandlerMethod.getMethodArgumentValues(InvocableHandlerMethod.java:157) ~[spring-web-4.1.1.BUILD-20140924.155845-31.jar:4.1.1.BUILD-SNAPSHOT]
	at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:124) ~[spring-web-4.1.1.BUILD-20140924.155845-31.jar:4.1.1.BUILD-SNAPSHOT]
	at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:104) ~[spring-webmvc-4.1.1.BUILD-20140924.155845-31.jar:4.1.1.BUILD-SNAPSHOT]
	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandleMethod(RequestMappingHandlerAdapter.java:781) ~[spring-webmvc-4.1.1.BUILD-20140924.155845-31.jar:4.1.1.BUILD-SNAPSHOT]
	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:721) ~[spring-webmvc-4.1.1.BUILD-20140924.155845-31.jar:4.1.1.BUILD-SNAPSHOT]
	at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:83) ~[spring-webmvc-4.1.1.BUILD-20140924.155845-31.jar:4.1.1.BUILD-SNAPSHOT]
	at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:943) ~[spring-webmvc-4.1.1.BUILD-20140924.155845-31.jar:4.1.1.BUILD-SNAPSHOT]
	at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:877) ~[spring-webmvc-4.1.1.BUILD-20140924.155845-31.jar:4.1.1.BUILD-SNAPSHOT]
	at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:966) [spring-webmvc-4.1.1.BUILD-20140924.155845-31.jar:4.1.1.BUILD-SNAPSHOT]
	at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:857) [spring-webmvc-4.1.1.BUILD-20140924.155845-31.jar:4.1.1.BUILD-SNAPSHOT]
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:687) ~[javax.servlet-api-3.1.0.jar:3.1.0]
	at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:842) [spring-webmvc-4.1.1.BUILD-20140924.155845-31.jar:4.1.1.BUILD-SNAPSHOT]
	at org.springframework.test.web.servlet.TestDispatcherServlet.service(TestDispatcherServlet.java:62) [spring-test-4.1.1.BUILD-20140924.155845-31.jar:4.1.1.BUILD-SNAPSHOT]
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:790) ~[javax.servlet-api-3.1.0.jar:3.1.0]
	at org.springframework.mock.web.MockFilterChain$ServletFilterProxy.doFilter(MockFilterChain.java:170) [spring-test-4.1.1.BUILD-20140924.155845-31.jar:4.1.1.BUILD-SNAPSHOT]
	at org.springframework.mock.web.MockFilterChain.doFilter(MockFilterChain.java:137) [spring-test-4.1.1.BUILD-20140924.155845-31.jar:4.1.1.BUILD-SNAPSHOT]
	at org.springframework.test.web.servlet.MockMvc.perform(MockMvc.java:145) [spring-test-4.1.1.BUILD-20140924.155845-31.jar:4.1.1.BUILD-SNAPSHOT]
	at com.despegar.bookedia.cancelpolicy.CustomCancelPolicyControllerTest.get_sortedListByName_okStatus(CustomCancelPolicyControllerTest.java:150) [test-classes/:na]
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_05]
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_05]
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_05]
	at java.lang.reflect.Method.invoke(Method.java:483) ~[na:1.8.0_05]
	at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:47) [junit-4.11.jar:na]
	at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12) [junit-4.11.jar:na]
	at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:44) [junit-4.11.jar:na]
	at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17) [junit-4.11.jar:na]
	at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:26) [junit-4.11.jar:na]
	at org.springframework.test.context.junit4.statements.RunBeforeTestMethodCallbacks.evaluate(RunBeforeTestMethodCallbacks.java:72) [spring-test-4.1.1.BUILD-20140924.155845-31.jar:4.1.1.BUILD-SNAPSHOT]
	at org.springframework.test.context.junit4.statements.RunAfterTestMethodCallbacks.evaluate(RunAfterTestMethodCallbacks.java:81) [spring-test-4.1.1.BUILD-20140924.155845-31.jar:4.1.1.BUILD-SNAPSHOT]
	at org.springframework.test.context.junit4.statements.SpringRepeat.evaluate(SpringRepeat.java:72) [spring-test-4.1.1.BUILD-20140924.155845-31.jar:4.1.1.BUILD-SNAPSHOT]
	at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:271) [junit-4.11.jar:na]
	at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:216) [spring-test-4.1.1.BUILD-20140924.155845-31.jar:4.1.1.BUILD-SNAPSHOT]
	at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:82) [spring-test-4.1.1.BUILD-20140924.155845-31.jar:4.1.1.BUILD-SNAPSHOT]
	at org.junit.runners.ParentRunner$3.run(ParentRunner.java:238) [junit-4.11.jar:na]
	at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:63) [junit-4.11.jar:na]
	at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:236) [junit-4.11.jar:na]
	at org.junit.runners.ParentRunner.access$000(ParentRunner.java:53) [junit-4.11.jar:na]
	at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:229) [junit-4.11.jar:na]
	at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:60) [spring-test-4.1.1.BUILD-20140924.155845-31.jar:4.1.1.BUILD-SNAPSHOT]
	at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:67) [spring-test-4.1.1.BUILD-20140924.155845-31.jar:4.1.1.BUILD-SNAPSHOT]
	at org.junit.runners.ParentRunner.run(ParentRunner.java:309) [junit-4.11.jar:na]
	at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:162) [spring-test-4.1.1.BUILD-20140924.155845-31.jar:4.1.1.BUILD-SNAPSHOT]
	at org.junit.runner.JUnitCore.run(JUnitCore.java:160) [junit-4.11.jar:na]
	at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:74) [junit-rt.jar:na]
	at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:211) [junit-rt.jar:na]
	at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:67) [junit-rt.jar:na]

[spring-projects-issues]

Juergen Hoeller commented

I figured it'd be a top-level binding target like in that stacktrace... Note that we are rejecting a null value in such a scenario since we can't bind any properties against a null target; with the same reasoning, we're rejecting an empty Optional object as well.

So I'm wondering: What would you expect to happen in such a case? Any incoming property values could not get bound since there's no target object... Would you expect that to fail later - i.e. on actual binding of a property value, with possibly none specified anyway, therefore effectively skipping the binding step?

Juergen

[spring-projects-issues]

Federico Donnarumma commented

I don't get why it's failing. We are using a custom validator that validates the object inside the Optional so if the controller is mapping that to an empty optional that seems fine, can you clarify a little more?

Thanks in advance.

[spring-projects-issues]

Federico Donnarumma commented

what do you think about this?

public static Object unwrap(Object optionalObject) {
    Optional<?> optional = (Optional<?>) optionalObject;
        if(optional.isPresent()) {
            return optional.get();
        } else {
            return Optional.empty();
        }
}

[spring-projects-issues]

Juergen Hoeller commented

Ah, that problem seems to be in ModelAttributeMethodProcessor which does a plain not-null check and ends up triggering the bind step that way... I guess we have to check for not-empty Optional objects there as well, i.e. at the DataBinder level.

In any case, an empty Optional object ending up as top-level object in BeanWrapperImpl is pointless, so the assertion there is correct from my perspective. It's the code that triggers the bind step which needs to defend itself against empty Optional objects; I'll do a revision of all such places in the codebase.

Juergen