put date date_nanos implicit casting rule behind snapshot

Author: fang-xing-esql

x-pack/plugin/esql/src/main/java/org/elasticsearch/xpack/esql/analysis/Analyzer.java

@@ -134,6 +134,7 @@
 import static java.util.Collections.emptyList;
 import static java.util.Collections.singletonList;
 import static org.elasticsearch.xpack.core.enrich.EnrichPolicy.GEO_MATCH_TYPE;
+import static org.elasticsearch.xpack.esql.action.EsqlCapabilities.Cap.IMPLICIT_CASTING_DATE_AND_DATE_NANOS;
 import static org.elasticsearch.xpack.esql.core.type.DataType.BOOLEAN;
 import static org.elasticsearch.xpack.esql.core.type.DataType.DATETIME;
 import static org.elasticsearch.xpack.esql.core.type.DataType.DATE_NANOS;
@@ -1819,10 +1820,6 @@ private static boolean canConvertOriginalTypes(MultiTypeEsField multiTypeEsField
 
         private static Expression typeSpecificConvert(ConvertFunction convert, Source source, DataType type, InvalidMappedField mtf) {
             EsField field = new EsField(mtf.getName(), type, mtf.getProperties(), mtf.isAggregatable());
-            return typeSpecificConvert(convert, source, field);
-        }
-
-        private static Expression typeSpecificConvert(ConvertFunction convert, Source source, EsField field) {
             FieldAttribute originalFieldAttr = (FieldAttribute) convert.field();
             FieldAttribute resolvedAttr = new FieldAttribute(
                 source,
@@ -1904,6 +1901,9 @@ private static LogicalPlan planWithoutSyntheticAttributes(LogicalPlan plan) {
     private static class DateMillisToNanosInEsRelation extends Rule<LogicalPlan, LogicalPlan> {
         @Override
         public LogicalPlan apply(LogicalPlan plan) {
+            if (IMPLICIT_CASTING_DATE_AND_DATE_NANOS.isEnabled() == false) {
+                return plan;
+            }
             return plan.transformUp(EsRelation.class, relation -> {
                 if (relation.indexMode() == IndexMode.LOOKUP) {
                     return relation;