ESQL: Verifier failure to catch aggregation functions outside STATS command #124311
Description
Description
In theory, the Verifier should prevent queries that use aggregation functions to be used outside an aggregation "context", meaning the stats command. For example, from employees | eval x = min(languages) returns a 400 error message
line 1:27: aggregate function [min(languages)] not allowed outside STATS command
While from employees | where min(languages) > 2 returns a 500 error:
path: /_query, params: {format=txt, error_trace=true}, status: 500 org.elasticsearch.xpack.esql.core.QlIllegalArgumentException: Unsupported expression [min(languages)]
at org.elasticsearch.xpack.esql.evaluator.EvalMapper.toEvaluator(EvalMapper.java:96)
at org.elasticsearch.xpack.esql.evaluator.EvalMapper$1.apply(EvalMapper.java:77)
at org.elasticsearch.xpack.esql.expression.predicate.operator.comparison.EsqlBinaryComparison.toEvaluator(EsqlBinaryComparison.java:227)
at org.elasticsearch.xpack.esql.evaluator.EvalMapper.toEvaluator(EvalMapper.java:74)
at org.elasticsearch.xpack.esql.planner.LocalExecutionPlanner.planFilter(LocalExecutionPlanner.java:700)
The failure to map the where command shouldn't happen, instead the behavior should be caught early on by the Verifier, just like the first scenario.