ClassCastException in EsqlFunctionRegistry

[rjernst]

I encountered a ClassCastException within LinkedHashMap used by ESQL.

 Caused by:	
  java.lang.ClassCastException: class java.util.LinkedHashMap$Entry cannot be cast to class java.util.HashMap$TreeNode (java.util.LinkedHashMap$Entry and java.util.HashMap$TreeNode are in module java.base of loader 'bootstrap')	
      at java.base/java.util.HashMap$TreeNode.moveRootToFront(HashMap.java:1995)	
      at java.base/java.util.HashMap$TreeNode.treeify(HashMap.java:2111)	
      at java.base/java.util.HashMap.treeifyBin(HashMap.java:779)	
      at java.base/java.util.HashMap.putVal(HashMap.java:651)	
      at java.base/java.util.HashMap.put(HashMap.java:619)	
      at org.elasticsearch.xpack.esql.expression.function.EsqlFunctionRegistry.buildDataTypesForStringLiteralConversion(EsqlFunctionRegistry.java:718)	
      at org.elasticsearch.xpack.esql.expression.function.EsqlFunctionRegistry.<init>(EsqlFunctionRegistry.java:234)

See https://gradle-enterprise.elastic.co/s/fwqg4ibahnj4s/console-log/task/:x-pack:plugin:esql:internalClusterTest?page=1

I wonder if this is due to concurrent modification?

[elasticsearchmachine]

Pinging @elastic/es-analytical-engine (Team:Analytics)

[ivancea]

Hey!
Thanks for reporting; there's indeed a static field being accessed from a constructor there, that shouldn't happen.
Related to this, there's also a minor bug here with snapshot-only functions, because of that static field. Or so I think. I'll check it and open a PR