SimpleAliasRegistry.canonicalName can produce an endless loop [SPR-7274]

[spring-projects-issues]

Joern Huxhorn opened SPR-7274 and commented

The corresponding stacktrace looks like this:

"main" prio=5 tid=102800800 nid=0x100501000 runnable [1004ff000]
java.lang.Thread.State: RUNNABLE
at org.springframework.core.SimpleAliasRegistry.canonicalName(SimpleAliasRegistry.java:156)
at org.springframework.beans.factory.support.AbstractBeanFactory.transformedBeanName(AbstractBeanFactory.java:966)
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:230)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:190)
at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveReference(BeanDefinitionValueResolver.java:322)
at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveValueIfNecessary(BeanDefinitionValueResolver.java:106)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyPropertyValues(AbstractAutowireCapableBeanFactory.java:1317)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1076)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:517)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:456)
at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:291)
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222)

• locked <107d35848> (a java.util.concurrent.ConcurrentHashMap)
  at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:288)
  at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:190)
  at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:563)
• locked <107d35a40> (a java.util.concurrent.ConcurrentHashMap)
  at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:872)
  at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:423)
• locked <107d06848> (a java.lang.Object)
  at org.springframework.context.support.ClassPathXmlApplicationContext.<init>(ClassPathXmlApplicationContext.java:139)
  at org.springframework.context.support.ClassPathXmlApplicationContext.<init>(ClassPathXmlApplicationContext.java:93)

The endless loop is in line 156:
/**

• Determine the raw name, resolving aliases to canonical names.
• @param name the user-specified name
• @return the transformed name
  */
  public String canonicalName(String name) {
  String canonicalName = name;
  // Handle aliasing.
  String resolvedName = null;
  do {
  resolvedName = this.aliasMap.get(canonicalName);
  if (resolvedName != null) {
  canonicalName = resolvedName;
  }
  }
  while (resolvedName != null); // <= here
  return canonicalName;
  }

I have this hang in a quite complex config file and I guess that there is some kind of alias loop. This, however, shouldn't result in an endless loop but in some useful error message containing the "loop path" of the aliases.

---

Affects: 3.0.2

Referenced from: commits 11330ba

[spring-projects-issues]

Joern Huxhorn commented

Suggested fix (untested, I didn't even compile;)):
{{ public String canonicalName(String name) {
String canonicalName = name;
List<String> loopCheck=new ArrayList<String>();
loopCheck.add(name);
// Handle aliasing.
for(;;) {
String resolvedName = this.aliasMap.get(canonicalName);
if (resolvedName != null) {
if(loopCheck.contains(resolvedName)) {
throw new IllegalStateException("Alias '"+name+"' is part of a loop ("+loopCheck+")!");
}
loopCheck.add(resolvedName);

			canonicalName = resolvedName;
		} else {
			break;
		}
	}
	return canonicalName;
}

}}

[spring-projects-issues]

Juergen Hoeller commented

Good catch! Fixed for 3.0.3, in registerAlias so that it is being detected early and avoids runtime overhead in canonicalName itself. This will be available in tonight's 3.0.3 snapshot - feel free to give it an early try...

Juergen