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[CLJ-1246] type-reflect with AsmReflector throws exceptions for classes with annotations Created: 21/Aug/13  Updated: 25/Oct/13  Resolved: 25/Oct/13

Status: Closed
Project: Clojure
Component/s: None
Affects Version/s: Release 1.6
Fix Version/s: Release 1.6

Type: Defect Priority: Major
Reporter: Andy Fingerhut Assignee: Unassigned
Resolution: Completed Votes: 1
Labels: interop

Attachments: File clj-1246-fix-type-reflect-exception-patch-v1.diff     Text File clj-1246-fix-type-reflect-exception-patch-v1.txt    
Patch: Code and Test
Approval: Ok

 Description   

REPL session reproducing the problem:

% java -cp clojure.jar clojure.main
Clojure 1.6.0-master-SNAPSHOT
user=> (use 'clojure.reflect)
nil
user=> (import '[clojure.reflect AsmReflector])
clojure.reflect.AsmReflector
user=> (def cl (.getContextClassLoader (Thread/currentThread)))
#'user/cl
user=> (def asm-reflector (AsmReflector. cl))
#'user/asm-reflector
user=> (type-reflect 'java.lang.SuppressWarnings :reflector asm-reflector)
AbstractMethodError clojure.reflect.AsmReflector$reify__9181.visitAnnotation(Ljava/lang/String;Z)Lclojure/asm/AnnotationVisitor;  clojure.asm.ClassReader.accept (ClassReader.java:593)

Issue discovered when trying out a build of Clojure source code with JDK8 early access version b103. In Clojure's set of tests, one of the classes tested with type-reflect fails with JDK8 because annotations were added to that class in JDK8, but it did not have annotations in earlier JDK versions. The same issue exists with JDK6 and JDK7 for any class with annotations, though – it is not unique to JDK8.

Analysis:

Definition of AsmReflector type in src/clj/clojure/reflect/java.clj has a reify for a ClassVisitor with no definition for a visitAnnotation method. This method is called for classes with annotations.

Patch: clj-1246-fix-type-reflect-exception-patch-v1.diff
Screened by: Alex Miller



 Comments   
Comment by Andy Fingerhut [ 21/Aug/13 8:04 PM ]

Patch clj-1246-fix-type-reflect-exception-patch-v1.txt dated Aug 21 2013 eliminates the exception by implementing the visitAnnotation method in the ClassVisitor object of the AsmReflector implementation. The implementation simply returns nil, which is enough for the caller to keep going through the class definition, ignoring any annotations.

Comment by Alex Miller [ 22/Oct/13 9:25 PM ]

Is there any reason for the addition of SuppressWarnings in the test file?

Comment by Andy Fingerhut [ 22/Oct/13 9:52 PM ]

I added that because that new test fails on JDK6 and 7 without the patch. Without the additional test, the bug is not exposed by any existing tests unless you run on JDK8.

Comment by Alex Miller [ 23/Oct/13 10:56 PM ]

What new test? I just see the SuppressWarnings import?

Comment by Andy Fingerhut [ 24/Oct/13 9:05 AM ]

The line where java.lang.SuppressWarnings is added is not an import, but naming another class in a sequence of classes being iterated over via doseq in a test.

Comment by Alex Miller [ 24/Oct/13 2:14 PM ]

Ah, thank you. Diff blindness.

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