Readability.

Author: afoucret

x-pack/plugin/esql/src/main/java/org/elasticsearch/xpack/esql/parser/LogicalPlanBuilder.java

@@ -790,7 +790,9 @@ private UnresolvedAttribute visitRerankScoreAttribute(String optionName, EsqlBas
             throw new ParsingException(source(ctx), "Parameter [{}] is null or undefined", optionName);
         }
 
-        Expression optionValue = ctx.identifier() != null ? Literal.keyword(source(ctx.identifier()), visitIdentifier(ctx.identifier())) : expression(ctx.constant());
+        Expression optionValue = ctx.identifier() != null
+            ? Literal.keyword(source(ctx.identifier()), visitIdentifier(ctx.identifier()))
+            : expression(ctx.constant());
 
         if (optionValue instanceof UnresolvedAttribute scoreAttribute) {
             return scoreAttribute;

x-pack/plugin/esql/src/main/java/org/elasticsearch/xpack/esql/plan/logical/inference/Rerank.java

@@ -24,7 +24,6 @@
 import org.elasticsearch.xpack.esql.core.expression.UnresolvedAttribute;
 import org.elasticsearch.xpack.esql.core.tree.NodeInfo;
 import org.elasticsearch.xpack.esql.core.tree.Source;
-import org.elasticsearch.xpack.esql.core.type.DataType;
 import org.elasticsearch.xpack.esql.io.stream.PlanStreamInput;
 import org.elasticsearch.xpack.esql.plan.logical.LogicalPlan;
 import org.elasticsearch.xpack.esql.plan.logical.UnaryPlan;

x-pack/plugin/esql/src/main/java/org/elasticsearch/xpack/esql/planner/LocalExecutionPlanner.java

@@ -620,6 +620,13 @@ private PhysicalOperation planRerank(RerankExec rerank, LocalExecutionPlannerCon
 
         EvalOperator.ExpressionEvaluator.Factory rowEncoderFactory;
         if (rerank.rerankFields().size() > 1) {
+            // If there is more than one field used for reranking we are encoded the input in a YAML doc, using field names as key.
+            // The input value will looks like
+            // text_field: foo bar
+            // multivalue_text_field:
+            //   - value 1
+            //   - value 2
+            // integer_field: 132
             Map<ColumnInfoImpl, EvalOperator.ExpressionEvaluator.Factory> rerankFieldsEvaluatorSuppliers = Maps
                 .newLinkedHashMapWithExpectedSize(rerank.rerankFields().size());