Test partial fix for top

Author: julian-elastic

x-pack/plugin/esql/src/main/java/org/elasticsearch/xpack/esql/expression/function/aggregate/Top.java

@@ -42,7 +42,7 @@
 import static org.elasticsearch.xpack.esql.core.expression.TypeResolutions.ParamOrdinal.FIRST;
 import static org.elasticsearch.xpack.esql.core.expression.TypeResolutions.ParamOrdinal.SECOND;
 import static org.elasticsearch.xpack.esql.core.expression.TypeResolutions.ParamOrdinal.THIRD;
-import static org.elasticsearch.xpack.esql.core.expression.TypeResolutions.isNotNullAndFoldable;
+import static org.elasticsearch.xpack.esql.core.expression.TypeResolutions.isNotNull;
 import static org.elasticsearch.xpack.esql.core.expression.TypeResolutions.isString;
 import static org.elasticsearch.xpack.esql.core.expression.TypeResolutions.isType;
 
@@ -116,8 +116,8 @@ Expression orderField() {
         return parameters().get(1);
     }
 
-    private int limitValue() {
-        return (int) limitField().fold(FoldContext.small() /* TODO remove me */);
+    private Integer limitValue() {
+        return (Integer) limitField().fold(FoldContext.small() /* TODO remove me */);
     }
 
     private String orderRawValue() {
@@ -148,23 +148,26 @@ protected TypeResolution resolveType() {
             "ip",
             "string",
             "numeric except unsigned_long or counter types"
-        ).and(isNotNullAndFoldable(limitField(), sourceText(), SECOND))
+        ).and(isNotNull(limitField(), sourceText(), SECOND))
             .and(isType(limitField(), dt -> dt == DataType.INTEGER, sourceText(), SECOND, "integer"))
-            .and(isNotNullAndFoldable(orderField(), sourceText(), THIRD))
+            .and(isNotNull(orderField(), sourceText(), THIRD))
             .and(isString(orderField(), sourceText(), THIRD));
 
         if (typeResolution.unresolved()) {
             return typeResolution;
         }
 
-        var limit = limitValue();
+        Integer limit = limitValue();
         var order = orderRawValue();
 
+        if (limit == null) {
+            return new TypeResolution(format(null, "Limit must be a constant integer in [{}], found [{}]", sourceText(), limit));
+        }
         if (limit <= 0) {
             return new TypeResolution(format(null, "Limit must be greater than 0 in [{}], found [{}]", sourceText(), limit));
         }
 
-        if (order.equalsIgnoreCase(ORDER_ASC) == false && order.equalsIgnoreCase(ORDER_DESC) == false) {
+        if (order == null || order.equalsIgnoreCase(ORDER_ASC) == false && order.equalsIgnoreCase(ORDER_DESC) == false) {
             return new TypeResolution(
                 format(null, "Invalid order value in [{}], expected [{}, {}] but got [{}]", sourceText(), ORDER_ASC, ORDER_DESC, order)
             );

x-pack/plugin/esql/src/test/java/org/elasticsearch/xpack/esql/expression/function/aggregate/TopTests.java

@@ -262,7 +262,7 @@ public static Iterable<Object[]> parameters() {
                             new TestCaseSupplier.TypedData(null, DataType.INTEGER, "limit").forceLiteral(),
                             new TestCaseSupplier.TypedData(new BytesRef("desc"), DataType.KEYWORD, "order").forceLiteral()
                         ),
-                        "second argument of [source] cannot be null, received [limit]"
+                        "Limit must be a constant integer in [source], found [null]"
                     )
                 ),
                 new TestCaseSupplier(
@@ -273,7 +273,7 @@ public static Iterable<Object[]> parameters() {
                             new TestCaseSupplier.TypedData(1, DataType.INTEGER, "limit").forceLiteral(),
                             new TestCaseSupplier.TypedData(null, DataType.KEYWORD, "order").forceLiteral()
                         ),
-                        "third argument of [source] cannot be null, received [order]"
+                        "Invalid order value in [source], expected [ASC, DESC] but got [null]"
                     )
                 )
             )