[jboss-jira] [JBoss JIRA] (JASSIST-188) CtClass detach does not completely clean class from pool.

[J D (JIRA)]

J D created JASSIST-188:
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             Summary: CtClass detach does not completely clean class from pool.
                 Key: JASSIST-188
                 URL: https://issues.jboss.org/browse/JASSIST-188
             Project: Javassist
          Issue Type: Bug
    Affects Versions: 3.17.0-GA
         Environment: Ubuntu, Windows, JDK 1.6/1.7
            Reporter: J D
            Assignee: Shigeru Chiba
            Priority: Critical


Description:

Class with same qualified name cannot be recreated even if previous class was detached  successfully from pool. 

Creation#1: Consider class eg.foo.MyClass is created using default pool and private int myArg1 private member along with some getter/setter methods. After its creation, the CtClass.detach is invoked successfully.

Creation#2: Subsequently, create eg.foo.MyClass using same default pool succeeds but any attempt to add members e.g. private int myArg1 fails with error: 

Field myArg1 in eg.foo.MyClass is private. 


Bug Analysis:
MemberCodeGen.isAccessibleField has f.getDeclaringClass from Creation#1 but thisClass is from Creation#2. This  was traced to MemberResolver.invalidNamesMap. When Creation#1 detached the CtClass, it got removed from pool but not from the invalidNamesMap for default pool.  Subsequently when MemberResolver.lookupClass looks for "eg.foo.MyClass", the Creation#1's CtClass gets returned. This is a bug because that class was detached earlier and must not be reused for any processing - we are creating another instance because a new definition is needed for that class.

The bug is critical as erroneous unintended cached class definitions could be used even when not intended leading to potentially very severe runtime problems. Remember that cache is a good only if it accurately provided cached results. In this case, stale/incorrect results will be returned. 

Proposed Fix:
Add a static method detachInvalidNames in MemberResolver that removes a qualified class-name from invalidNamesMap for that class's pool. CtClass.detach must invoke this detachInvalidNames.

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