Address code review comments

Author: julian-elastic

x-pack/plugin/esql/src/main/java/org/elasticsearch/xpack/esql/enrich/EnrichPolicyResolver.java

@@ -59,7 +59,7 @@
 import java.util.Set;
 import java.util.stream.Collectors;
 
-import static org.elasticsearch.xpack.esql.expression.function.Foldables.stringLiteralValueOf;
+import static org.elasticsearch.xpack.esql.expression.Foldables.stringLiteralValueOf;
 import static org.elasticsearch.xpack.esql.session.EsqlCCSUtils.markClusterWithFinalStateAndNoShards;
 
 /**

x-pack/plugin/esql/src/main/java/org/elasticsearch/xpack/esql/expression/function/Foldables.java renamed to x-pack/plugin/esql/src/main/java/org/elasticsearch/xpack/esql/expression/Foldables.java

@@ -4,7 +4,7 @@
  * 2.0; you may not use this file except in compliance with the Elastic License
  * 2.0.
  */
-package org.elasticsearch.xpack.esql.expression.function;
+package org.elasticsearch.xpack.esql.expression;
 
 import org.apache.lucene.util.BytesRef;
 import org.elasticsearch.common.lucene.BytesRefs;
@@ -22,6 +22,51 @@
 import static org.elasticsearch.xpack.esql.common.Failure.fail;
 
 public abstract class Foldables {
+    /**
+     * A utility class to validate the type resolution of expressions before and after logical planning.
+     * If null is passed for Failures to the constructor, it means we are only type resolution.
+     * This is usually called when doing pre-logical planning validation.
+     * If a {@link Failures} instance is passed, it means we are doing post-logical planning validation as well.
+     * This is usually called after folding is done, during
+     * {@link org.elasticsearch.xpack.esql.capabilities.PostOptimizationVerificationAware} verification
+     */
+    public static class TypeResolutionValidator {
+
+        Expression.TypeResolution typeResolution = Expression.TypeResolution.TYPE_RESOLVED;
+        @Nullable
+        private final Failures postValidationFailures; // null means we are doing pre-folding validation only
+        private final Expression field;
+
+        public static TypeResolutionValidator forPreOptimizationValidation(Expression field) {
+            return new TypeResolutionValidator(field, null);
+        }
+
+        public static TypeResolutionValidator forPostOptimizationValidation(Expression field, Failures failures) {
+            return new TypeResolutionValidator(field, failures);
+        }
+
+        private TypeResolutionValidator(Expression field, Failures failures) {
+            this.field = field;
+            this.postValidationFailures = failures;
+        }
+
+        public void invalidIfPostValidation(Failure failure) {
+            if (postValidationFailures != null) {
+                postValidationFailures.add(failure);
+            }
+        }
+
+        public void invalid(Expression.TypeResolution message) {
+            typeResolution = message;
+            if (postValidationFailures != null) {
+                postValidationFailures.add(fail(field, message.message()));
+            }
+        }
+
+        public Expression.TypeResolution getResolvedType() {
+            return typeResolution;
+        }
+    }
 
     public static Object valueOf(FoldContext ctx, Expression e) {
         if (e.foldable()) {
@@ -144,50 +189,4 @@ public static int intValueOf(Expression field, String sourceText, String fieldNa
             Strings.format(null, "[{}] value must be a constant number in [{}], found [{}]", fieldName, sourceText, field)
         );
     }
-
-    /**
-     * A utility class to validate the type resolution of expressions before and after logical planning.
-     * If null is passed for Failures to the constructor, it means we are only type resolution.
-     * This is usually called when doing pre-logical planning validation.
-     * If a {@link Failures} instance is passed, it means we are doing post-logical planning validation as well.
-     * This is usually called after folding is done, during
-     * {@link org.elasticsearch.xpack.esql.capabilities.PostOptimizationVerificationAware} verification
-     */
-    public static class TypeResolutionValidator {
-
-        Expression.TypeResolution typeResolution = Expression.TypeResolution.TYPE_RESOLVED;
-        @Nullable
-        private final Failures postValidationFailures; // null means we are doing pre-folding validation only
-        private final Expression field;
-
-        public static TypeResolutionValidator forPreOptimizationValidation(Expression field) {
-            return new TypeResolutionValidator(field, null);
-        }
-
-        public static TypeResolutionValidator forPostOptimizationValidation(Expression field, Failures failures) {
-            return new TypeResolutionValidator(field, failures);
-        }
-
-        private TypeResolutionValidator(Expression field, Failures failures) {
-            this.field = field;
-            this.postValidationFailures = failures;
-        }
-
-        public void invalidIfPostValidation(Failure failure) {
-            if (postValidationFailures != null) {
-                postValidationFailures.add(failure);
-            }
-        }
-
-        public void invalid(Expression.TypeResolution message) {
-            typeResolution = message;
-            if (postValidationFailures != null) {
-                postValidationFailures.add(fail(field, message.message()));
-            }
-        }
-
-        public Expression.TypeResolution getResolvedType() {
-            return typeResolution;
-        }
-    }
 }

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

@@ -48,7 +48,7 @@
 import static org.elasticsearch.xpack.esql.core.expression.TypeResolutions.isType;
 import static org.elasticsearch.xpack.esql.core.expression.TypeResolutions.isWholeNumber;
 import static org.elasticsearch.xpack.esql.core.util.CollectionUtils.nullSafeList;
-import static org.elasticsearch.xpack.esql.expression.function.Foldables.intValueOf;
+import static org.elasticsearch.xpack.esql.expression.Foldables.intValueOf;
 
 public class CountDistinct extends AggregateFunction implements OptionalArgument, ToAggregator, SurrogateExpression {
     public static final NamedWriteableRegistry.Entry ENTRY = new NamedWriteableRegistry.Entry(

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

@@ -37,7 +37,7 @@
 import static org.elasticsearch.xpack.esql.core.expression.TypeResolutions.ParamOrdinal.SECOND;
 import static org.elasticsearch.xpack.esql.core.expression.TypeResolutions.isFoldable;
 import static org.elasticsearch.xpack.esql.core.expression.TypeResolutions.isType;
-import static org.elasticsearch.xpack.esql.expression.function.Foldables.intValueOf;
+import static org.elasticsearch.xpack.esql.expression.Foldables.intValueOf;
 
 public class Percentile extends NumericAggregate implements SurrogateExpression {
     public static final NamedWriteableRegistry.Entry ENTRY = new NamedWriteableRegistry.Entry(

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

@@ -24,8 +24,8 @@
 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.expression.Foldables;
 import org.elasticsearch.xpack.esql.expression.function.Example;
-import org.elasticsearch.xpack.esql.expression.function.Foldables;
 import org.elasticsearch.xpack.esql.expression.function.FunctionAppliesTo;
 import org.elasticsearch.xpack.esql.expression.function.FunctionAppliesToLifecycle;
 import org.elasticsearch.xpack.esql.expression.function.FunctionInfo;
@@ -42,9 +42,9 @@
 import static org.elasticsearch.xpack.esql.core.expression.TypeResolutions.isNotNull;
 import static org.elasticsearch.xpack.esql.core.expression.TypeResolutions.isRepresentableExceptCounters;
 import static org.elasticsearch.xpack.esql.core.expression.TypeResolutions.isType;
-import static org.elasticsearch.xpack.esql.expression.function.Foldables.TypeResolutionValidator.forPostOptimizationValidation;
-import static org.elasticsearch.xpack.esql.expression.function.Foldables.TypeResolutionValidator.forPreOptimizationValidation;
-import static org.elasticsearch.xpack.esql.expression.function.Foldables.resolveTypeLimit;
+import static org.elasticsearch.xpack.esql.expression.Foldables.TypeResolutionValidator.forPostOptimizationValidation;
+import static org.elasticsearch.xpack.esql.expression.Foldables.TypeResolutionValidator.forPreOptimizationValidation;
+import static org.elasticsearch.xpack.esql.expression.Foldables.resolveTypeLimit;
 
 public class Sample extends AggregateFunction implements ToAggregator, PostOptimizationVerificationAware {
     public static final NamedWriteableRegistry.Entry ENTRY = new NamedWriteableRegistry.Entry(Expression.class, "Sample", Sample::new);

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

@@ -27,10 +27,10 @@
 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.expression.Foldables;
+import org.elasticsearch.xpack.esql.expression.Foldables.TypeResolutionValidator;
 import org.elasticsearch.xpack.esql.expression.SurrogateExpression;
 import org.elasticsearch.xpack.esql.expression.function.Example;
-import org.elasticsearch.xpack.esql.expression.function.Foldables;
-import org.elasticsearch.xpack.esql.expression.function.Foldables.TypeResolutionValidator;
 import org.elasticsearch.xpack.esql.expression.function.FunctionInfo;
 import org.elasticsearch.xpack.esql.expression.function.FunctionType;
 import org.elasticsearch.xpack.esql.expression.function.Param;
@@ -49,8 +49,8 @@
 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;
-import static org.elasticsearch.xpack.esql.expression.function.Foldables.TypeResolutionValidator.forPostOptimizationValidation;
-import static org.elasticsearch.xpack.esql.expression.function.Foldables.TypeResolutionValidator.forPreOptimizationValidation;
+import static org.elasticsearch.xpack.esql.expression.Foldables.TypeResolutionValidator.forPostOptimizationValidation;
+import static org.elasticsearch.xpack.esql.expression.Foldables.TypeResolutionValidator.forPreOptimizationValidation;
 
 public class Top extends AggregateFunction implements ToAggregator, SurrogateExpression, PostOptimizationVerificationAware {
     public static final NamedWriteableRegistry.Entry ENTRY = new NamedWriteableRegistry.Entry(Expression.class, "Top", Top::new);

x-pack/plugin/esql/src/main/java/org/elasticsearch/xpack/esql/expression/function/fulltext/FullTextFunction.java

@@ -56,9 +56,9 @@
 import static org.elasticsearch.xpack.esql.core.expression.TypeResolutions.ParamOrdinal.DEFAULT;
 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.expression.function.Foldables.TypeResolutionValidator.forPostOptimizationValidation;
-import static org.elasticsearch.xpack.esql.expression.function.Foldables.TypeResolutionValidator.forPreOptimizationValidation;
-import static org.elasticsearch.xpack.esql.expression.function.Foldables.resolveTypeQuery;
+import static org.elasticsearch.xpack.esql.expression.Foldables.TypeResolutionValidator.forPostOptimizationValidation;
+import static org.elasticsearch.xpack.esql.expression.Foldables.TypeResolutionValidator.forPreOptimizationValidation;
+import static org.elasticsearch.xpack.esql.expression.Foldables.resolveTypeQuery;
 
 /**
  * Base class for full-text functions that use ES queries to match documents.

x-pack/plugin/esql/src/main/java/org/elasticsearch/xpack/esql/expression/function/fulltext/Kql.java

@@ -16,8 +16,8 @@
 import org.elasticsearch.xpack.esql.core.querydsl.query.Query;
 import org.elasticsearch.xpack.esql.core.tree.NodeInfo;
 import org.elasticsearch.xpack.esql.core.tree.Source;
+import org.elasticsearch.xpack.esql.expression.Foldables;
 import org.elasticsearch.xpack.esql.expression.function.Example;
-import org.elasticsearch.xpack.esql.expression.function.Foldables;
 import org.elasticsearch.xpack.esql.expression.function.FunctionAppliesTo;
 import org.elasticsearch.xpack.esql.expression.function.FunctionAppliesToLifecycle;
 import org.elasticsearch.xpack.esql.expression.function.FunctionInfo;

x-pack/plugin/esql/src/main/java/org/elasticsearch/xpack/esql/expression/function/fulltext/Match.java

@@ -26,8 +26,8 @@
 import org.elasticsearch.xpack.esql.core.type.DataType;
 import org.elasticsearch.xpack.esql.core.util.Check;
 import org.elasticsearch.xpack.esql.core.util.NumericUtils;
+import org.elasticsearch.xpack.esql.expression.Foldables;
 import org.elasticsearch.xpack.esql.expression.function.Example;
-import org.elasticsearch.xpack.esql.expression.function.Foldables;
 import org.elasticsearch.xpack.esql.expression.function.FunctionAppliesTo;
 import org.elasticsearch.xpack.esql.expression.function.FunctionAppliesToLifecycle;
 import org.elasticsearch.xpack.esql.expression.function.FunctionInfo;
@@ -79,8 +79,8 @@
 import static org.elasticsearch.xpack.esql.core.type.DataType.TEXT;
 import static org.elasticsearch.xpack.esql.core.type.DataType.UNSIGNED_LONG;
 import static org.elasticsearch.xpack.esql.core.type.DataType.VERSION;
-import static org.elasticsearch.xpack.esql.expression.function.Foldables.TypeResolutionValidator.forPreOptimizationValidation;
-import static org.elasticsearch.xpack.esql.expression.function.Foldables.resolveTypeQuery;
+import static org.elasticsearch.xpack.esql.expression.Foldables.TypeResolutionValidator.forPreOptimizationValidation;
+import static org.elasticsearch.xpack.esql.expression.Foldables.resolveTypeQuery;
 import static org.elasticsearch.xpack.esql.expression.predicate.operator.comparison.EsqlBinaryComparison.formatIncompatibleTypesMessage;
 
 /**

x-pack/plugin/esql/src/main/java/org/elasticsearch/xpack/esql/expression/function/fulltext/MatchPhrase.java

@@ -23,8 +23,8 @@
 import org.elasticsearch.xpack.esql.core.tree.Source;
 import org.elasticsearch.xpack.esql.core.type.DataType;
 import org.elasticsearch.xpack.esql.core.util.Check;
+import org.elasticsearch.xpack.esql.expression.Foldables;
 import org.elasticsearch.xpack.esql.expression.function.Example;
-import org.elasticsearch.xpack.esql.expression.function.Foldables;
 import org.elasticsearch.xpack.esql.expression.function.FunctionAppliesTo;
 import org.elasticsearch.xpack.esql.expression.function.FunctionAppliesToLifecycle;
 import org.elasticsearch.xpack.esql.expression.function.FunctionInfo;
@@ -62,8 +62,8 @@
 import static org.elasticsearch.xpack.esql.core.type.DataType.INTEGER;
 import static org.elasticsearch.xpack.esql.core.type.DataType.KEYWORD;
 import static org.elasticsearch.xpack.esql.core.type.DataType.TEXT;
-import static org.elasticsearch.xpack.esql.expression.function.Foldables.TypeResolutionValidator.forPreOptimizationValidation;
-import static org.elasticsearch.xpack.esql.expression.function.Foldables.resolveTypeQuery;
+import static org.elasticsearch.xpack.esql.expression.Foldables.TypeResolutionValidator.forPreOptimizationValidation;
+import static org.elasticsearch.xpack.esql.expression.Foldables.resolveTypeQuery;
 
 /**
  * Full text function that performs a {@link org.elasticsearch.xpack.esql.querydsl.query.MatchPhraseQuery} .