Converters don't get picked up for MVC controllers in 3.0.7 [SPR-9157]

[spring-projects-issues]

Ferenc Gratzer opened SPR-9157 and commented

The same converter class and xml config work with Spring 3.0.5 and 3.0.6, but not with 3.0.7. Only changing the Spring version breaks it.

public class EnvironmentConverter implements Converter<String, Environment> {
  public Environment convert(String source) {}
}

servlet.xml:

<bean id="conversionService" class="org.springframework.context.support.ConversionServiceFactoryBean">
 <property name="converters">
   <set>
     <bean class="....controller.util.StringToEntityConverterFactory" />
     <bean class="....web.util.EnvironmentConverter" />
   </set>
 </property>
</bean>

Log:

org.springframework.beans.ConversionNotSupportedException: Failed to convert value of type 'java.lang.String' to required type '....environment.Environment'; nested exception is java.lang.IllegalStateException: Cannot convert value of type [java.lang.String] to required type [....environment.Environment]: no matching editors or conversion strategy found
	at org.springframework.beans.SimpleTypeConverter.convertIfNecessary(SimpleTypeConverter.java:58)
	at org.springframework.validation.DataBinder.convertIfNecessary(DataBinder.java:553)
	at org.springframework.web.bind.annotation.support.HandlerMethodInvoker.resolveRequestParam(HandlerMethodInvoker.java:507)
	at org.springframework.web.bind.annotation.support.HandlerMethodInvoker.resolveHandlerArguments(HandlerMethodInvoker.java:340)
	at org.springframework.web.bind.annotation.support.HandlerMethodInvoker.invokeHandlerMethod(HandlerMethodInvoker.java:171)
	at org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.invokeHandlerMethod(AnnotationMethodHandlerAdapter.java:436)
	at org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.handle(AnnotationMethodHandlerAdapter.java:424)
	at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:790)
	at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:719)
	at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:669)
	at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:585)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:710)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)

---

Affects: 3.0.7

[spring-projects-issues]

Rossen Stoyanchev commented

Added code formatting tags.

[spring-projects-issues]

Rossen Stoyanchev commented

It would help speed things up if you could help demonstrate the issue at the spring-framework-issues repository. There are template projects to help you do that quickly.

[spring-projects-issues]

Ferenc Gratzer commented

The sample project's created. However, the converter in this very little project without any security, interceptors etc. works fine.
The project the issue happens is much more complex.

On Friday I debugged the startup of the application and the converters seemed to be registered properly in GenericConversionService.
On Monday I'll look into the other end, into the DataBinder.

Any other idea where and what to look for to identify the cause of the issue?

[spring-projects-issues]

Chris Beams commented

pull request: spring-attic/spring-framework-issues#19

[spring-projects-issues]

Rossen Stoyanchev commented

I would put a breakpoint in AnnotationMethodHandlerAdapter when it's about to process the request (e.g. in invokeHandlerMethod()) and examine the webBindingInitializer property and the ConversionService it contains, does it have the custom converter? If not then there is some configuration you need to trace. If yes, then I would debug the call to the conversion service to see why it fails to find the converter even though it knows about it.

[spring-projects-issues]

Ferenc Gratzer commented

The demo for the issue is created.

I think the issue is on the line 432 in GenericConversionService.ConverterAdapter:
return this.typeInfo.getTargetType().equals(targetType.getObjectType());

In my view it should be:
return this.typeInfo.getTargetType().isAssignableFrom(targetType.getObjectType());

If you compare the version of 3.0.6 and 3.0.7 of GenericConversionService, you'll see that those lines were only added in 3.0.7.

[spring-projects-issues]

Rossen Stoyanchev commented

I see now. The converter is from String to Environment but the actual target object is a subtype of Environment. I think not allowing this is intentional since a Converter doesn't know what the actual target type expected is, it may return one that won't match. I I'll try to dig up the issue where this was change was made.

[spring-projects-issues]

Rossen Stoyanchev commented

The issue where this was addressed is #13360. I guess you'll need to use GenericConverter for something like that or depending on your needs perhaps a ConverterFactory.