Callgraph not generated in Apache Solr because of a method's token range being null

[openrefactorymunawar]

We ran on Apache Solr and after running a lot of time, it failed to generate a call graph. The error we were getting were.

2025-11-14T15:30:34.1500624Z 2025-11-14 07:30:34 PST [SERVER]: Call Graph Construction Complete
2025-11-14T15:45:16.8249110Z 2025-11-14 07:45:16 PST [SERVER]: Failed to generate cg file: Cannot invoke "org.openrefactory.util.datastructure.TokenRange.getOffset()" because "methodTr" is null
2025-11-14T15:45:16.8278010Z 2025-11-14 07:45:16 PST [SERVER]: Call graph generation complete

Looking deeper, the root cause seems to be an earlier Illegal Argument Exception,

2025-11-14T15:30:02.9506291Z java.lang.IllegalArgumentException: java.util.Map.Entry<capture#16-of ?,capture#17-of ?>
2025-11-14T15:30:02.9517578Z 	at org.eclipse.jdt.core.Signature.checkNextChar(Signature.java:1036)
2025-11-14T15:30:02.9520863Z 	at org.eclipse.jdt.core.Signature.encodeTypeSignature(Signature.java:1518)
2025-11-14T15:30:02.9521975Z 	at org.eclipse.jdt.core.Signature.createCharArrayTypeSignature(Signature.java:1106)
2025-11-14T15:30:02.9522895Z 	at org.eclipse.jdt.core.Signature.createTypeSignature(Signature.java:1304)
2025-11-14T15:30:02.9523902Z 	at org.eclipse.jdt.core.dom.VariableBinding.getUnresolvedJavaElement(VariableBinding.java:274)
2025-11-14T15:30:02.9524971Z 	at org.eclipse.jdt.core.dom.VariableBinding.getJavaElement(VariableBinding.java:161)
2025-11-14T15:30:02.9545831Z 	at org.openrefactory.util.ASTNodeUtility.getLocalVariableScope(ASTNodeUtility.java:936)
2025-11-14T15:30:02.9550685Z 	at org.openrefactory.analysis.type.TypeCalculator.getCallingContextType(TypeCalculator.java:179)
2025-11-14T15:30:02.9552327Z 	at org.openrefactory.util.CallGraphUtility.getCallingContextDeclaredTypeHashOfMethodInvocation(CallGraphUtility.java:1470)
2025-11-14T15:30:02.9553769Z 	at org.openrefactory.util.CallGraphUtility.getServicingMethodHashIndex(CallGraphUtility.java:1298)
2025-11-14T15:30:02.9555274Z 	at org.openrefactory.analysis.type.TypeCalculatorVisitor.visit(TypeCalculatorVisitor.java:547)
2025-11-14T15:30:02.9556283Z 	at org.eclipse.jdt.core.dom.MethodInvocation.accept0(MethodInvocation.java:220)
2025-11-14T15:30:02.9557052Z 	at org.eclipse.jdt.core.dom.ASTNode.accept(ASTNode.java:3312)
2025-11-14T15:30:02.9557975Z 	at org.openrefactory.analysis.type.TypeCalculator.getCallingContextType(TypeCalculator.java:177)
2025-11-14T15:30:02.9559391Z 	at org.openrefactory.util.CallGraphUtility.getCallingContextDeclaredTypeHashOfMethodInvocation(CallGraphUtility.java:1470)
2025-11-14T15:30:02.9560830Z 	at org.openrefactory.util.CallGraphUtility.getServicingMethodHashIndex(CallGraphUtility.java:1298)
2025-11-14T15:30:02.9562161Z 	at org.openrefactory.analysis.type.TypeCalculatorVisitor.visit(TypeCalculatorVisitor.java:547)
2025-11-14T15:30:02.9563150Z 	at org.eclipse.jdt.core.dom.MethodInvocation.accept0(MethodInvocation.java:220)
2025-11-14T15:30:02.9563911Z 	at org.eclipse.jdt.core.dom.ASTNode.accept(ASTNode.java:3312)
...
...

This is perhaps the reason why the methodTr was set to null.

We should do two things.

1. Fix the root cause (the Illegal Argument Exception)
2. Add a defensive check in the callgraph rendering part so that such failures do not cause the entire call graph generation to fail.