ComponentScanBeanDefinitionParser::parseTypeFilters should not fail on ClassNotFoundException [SPR-16356]

[spring-projects-issues]

Yanming Zhou opened SPR-16356 and commented

For example, parent project have such configuration to filter mvc and websocket component from root ApplicationContext, let them instantiated by child ApplicationContext

<context:component-scan base-package="com.acme">
     <context:exclude-filter type="annotation" expression="org.springframework.stereotype.Controller"/>
     <context:exclude-filter type="annotation" expression="org.springframework.web.bind.annotation.ControllerAdvice"/>
     <context:exclude-filter type="assignable" expression="org.springframework.web.servlet.config.annotation.WebMvcConfigurationSupport"/>
     <context:exclude-filter type="assignable" expression="org.springframework.web.socket.config.annotation.WebSocketConfigurer"/>
</context:component-scan>

Some projects reuse such configuration and without spring-websocket dependency, it will throws ClassNotFoundException.

Caused by: java.lang.ClassNotFoundException: org.springframework.web.socket.config.annotation.WebSocketConfigurer
	at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1333) ~[catalina.jar:8.0.44]
	at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1167) ~[catalina.jar:8.0.44]
	at org.springframework.util.ClassUtils.forName(ClassUtils.java:255) ~[spring-core-5.0.2.jar:5.0.2.RELEASE]
	at org.springframework.context.annotation.ComponentScanBeanDefinitionParser.createTypeFilter(ComponentScanBeanDefinitionParser.java:239) ~[spring-context-5.0.2.jar:5.0.2.RELEASE]
	at org.springframework.context.annotation.ComponentScanBeanDefinitionParser.parseTypeFilters(ComponentScanBeanDefinitionParser.java:215) ~[spring-context-5.0.2.jar:5.0.2.RELEASE]

I think spring should be lenient here, if class not present and the filter rule should ignore, at least "annotation" and "assignable" should do.

---

Affects: 4.3.13, 5.0.2

Referenced from: commits 092b3d4, 4adc820

Backported to: 4.3.14

[spring-projects-issues]

Juergen Hoeller commented

There is a fine line between configuration typos and 'optional' configuration elements that can safely be ignored. What we can easily do here is to lower the reporting level to "warning" which by default doesn't fail but rather logs a warn-level message; I'll apply this for 5.0.3 and 4.3.14.

You could customize your ProblemReporter configuration to completely ignore such warnings, that is, to log them at an even lower level or not at all. This requires custom configuration at the XmlBeanDefinitionReader level though, so might be rather inconvenient.

[spring-projects-issues]

Yanming Zhou commented

Thanks for quick response, warning is fine.