upd

Author: idegtiarenko

x-pack/plugin/esql-core/src/main/java/org/elasticsearch/xpack/esql/core/expression/Attribute.java

@@ -112,20 +112,15 @@ protected Expression canonicalize() {
     }
 
     @Override
+    @SuppressWarnings("checkstyle:EqualsHashCode")// equals is implemented in parent. See innerEquals instead
     public int hashCode() {
         return Objects.hash(super.hashCode(), nullability);
     }
 
     @Override
-    public boolean equals(Object obj) {
-        if (this == obj) {
-            return true;
-        }
-        if (obj == null || getClass() != obj.getClass() || super.equals(obj) == false) {
-            return false;
-        }
-        Attribute other = (Attribute) obj;
-        return Objects.equals(nullability, other.nullability);
+    protected boolean innerEquals(Object o) {
+        var other = (Attribute) o;
+        return super.innerEquals(other) && Objects.equals(nullability, other.nullability);
     }
 
     @Override

x-pack/plugin/esql-core/src/main/java/org/elasticsearch/xpack/esql/core/expression/EmptyAttribute.java

@@ -60,18 +60,13 @@ protected NodeInfo<? extends Expression> info() {
     }
 
     @Override
+    @SuppressWarnings("checkstyle:EqualsHashCode")// equals is implemented in parent. See innerEquals instead
     public int hashCode() {
         return EmptyAttribute.class.hashCode();
     }
 
     @Override
-    public boolean equals(Object obj) {
-        if (this == obj) {
-            return true;
-        }
-        if (obj == null || getClass() != obj.getClass()) {
-            return false;
-        }
+    protected boolean innerEquals(Object o) {
         return true;
     }
 }

x-pack/plugin/esql-core/src/main/java/org/elasticsearch/xpack/esql/core/expression/FieldAttribute.java

@@ -223,20 +223,15 @@ public Attribute withDataType(DataType type) {
     }
 
     @Override
-    public boolean equals(Object o) {
-        if (this == o) {
-            return true;
-        }
-        if (o == null || getClass() != o.getClass() || super.equals(o) == false) {
-            return false;
-        }
-        FieldAttribute that = (FieldAttribute) o;
-        return Objects.equals(parentName, that.parentName) && Objects.equals(field, that.field);
+    @SuppressWarnings("checkstyle:EqualsHashCode")// equals is implemented in parent. See innerEquals instead
+    public int hashCode() {
+        return Objects.hash(super.hashCode(), parentName, field);
     }
 
     @Override
-    public int hashCode() {
-        return Objects.hash(super.hashCode(), parentName, field);
+    protected boolean innerEquals(Object o) {
+        var other = (FieldAttribute) o;
+        return super.innerEquals(other) && Objects.equals(parentName, other.parentName) && Objects.equals(field, other.field);
     }
 
     @Override

x-pack/plugin/esql-core/src/main/java/org/elasticsearch/xpack/esql/core/expression/MetadataAttribute.java

@@ -173,19 +173,14 @@ public static boolean isSupported(String name) {
     }
 
     @Override
-    public boolean equals(Object o) {
-        if (this == o) {
-            return true;
-        }
-        if (o == null || getClass() != o.getClass() || super.equals(o) == false) {
-            return false;
-        }
-        MetadataAttribute that = (MetadataAttribute) o;
-        return searchable == that.searchable;
+    @SuppressWarnings("checkstyle:EqualsHashCode")// equals is implemented in parent. See innerEquals instead
+    public int hashCode() {
+        return Objects.hash(super.hashCode(), searchable);
     }
 
     @Override
-    public int hashCode() {
-        return Objects.hash(super.hashCode(), searchable);
+    protected boolean innerEquals(Object o) {
+        var other = (MetadataAttribute) o;
+        return super.innerEquals(other) && searchable == other.searchable;
     }
 }

x-pack/plugin/esql-core/src/main/java/org/elasticsearch/xpack/esql/core/expression/NamedExpression.java

@@ -61,15 +61,25 @@ public int hashCode() {
         return Objects.hash(super.hashCode(), name, synthetic);
     }
 
+    /**
+     * Polymorphic equality is a pain.
+     * This equals shortcuts `this == o` and type checks.
+     * Here equals is final to ensure we are not duplication those checks.
+     * For actual equality check override `innerEquals` instead.
+     */
     @Override
-    public boolean equals(Object obj) {
-        if (this == obj) {
+    public final boolean equals(Object o) {
+        if (this == o) {
             return true;
         }
-        if (obj == null || getClass() != obj.getClass()) {
+        if (o == null || getClass() != o.getClass()) {
             return false;
         }
-        NamedExpression other = (NamedExpression) obj;
+        return innerEquals(o);
+    }
+
+    protected boolean innerEquals(Object o) {
+        var other = (NamedExpression) o;
         return synthetic == other.synthetic
             /*
              * It is important that the line below be `name`

x-pack/plugin/esql-core/src/main/java/org/elasticsearch/xpack/esql/core/expression/TypedAttribute.java

@@ -34,19 +34,14 @@ public DataType dataType() {
     }
 
     @Override
-    public boolean equals(Object o) {
-        if (this == o) {
-            return true;
-        }
-        if (o == null || getClass() != o.getClass() || super.equals(o) == false) {
-            return false;
-        }
-        TypedAttribute that = (TypedAttribute) o;
-        return dataType == that.dataType;
+    @SuppressWarnings("checkstyle:EqualsHashCode")// equals is implemented in parent. See innerEquals instead
+    public int hashCode() {
+        return Objects.hash(super.hashCode(), dataType);
     }
 
     @Override
-    public int hashCode() {
-        return Objects.hash(super.hashCode(), dataType);
+    protected boolean innerEquals(Object o) {
+        var other = (TypedAttribute) o;
+        return super.innerEquals(other) && dataType == other.dataType;
     }
 }

x-pack/plugin/esql-core/src/main/java/org/elasticsearch/xpack/esql/core/expression/UnresolvedAttribute.java

@@ -119,21 +119,17 @@ public static String errorMessage(String name, List<String> potentialMatches) {
     }
 
     @Override
-    public boolean equals(Object o) {
-        if (this == o) {
-            return true;
-        }
-        if (o == null || getClass() != o.getClass() || super.equals(o) == false) {
-            return false;
-        }
-        UnresolvedAttribute that = (UnresolvedAttribute) o;
-        return customMessage == that.customMessage
-            && Objects.equals(unresolvedMsg, that.unresolvedMsg)
-            && Objects.equals(resolutionMetadata, that.resolutionMetadata);
+    @SuppressWarnings("checkstyle:EqualsHashCode")// equals is implemented in parent. See innerEquals instead
+    public int hashCode() {
+        return Objects.hash(super.hashCode(), resolutionMetadata, unresolvedMsg);
     }
 
     @Override
-    public int hashCode() {
-        return Objects.hash(super.hashCode(), resolutionMetadata, unresolvedMsg);
+    protected boolean innerEquals(Object o) {
+        var other = (UnresolvedAttribute) o;
+        return super.innerEquals(other)
+            && customMessage == other.customMessage
+            && Objects.equals(unresolvedMsg, other.unresolvedMsg)
+            && Objects.equals(resolutionMetadata, other.resolutionMetadata);
     }
 }

x-pack/plugin/esql-core/src/main/java/org/elasticsearch/xpack/esql/core/expression/UnresolvedStar.java

@@ -57,27 +57,15 @@ public UnresolvedAttribute qualifier() {
     }
 
     @Override
+    @SuppressWarnings("checkstyle:EqualsHashCode")// equals is implemented in parent. See innerEquals instead
     public int hashCode() {
         return Objects.hash(qualifier);
     }
 
     @Override
-    public boolean equals(Object obj) {
-        /*
-         * Intentionally not calling the superclass
-         * equals because it uses id which we always
-         * mutate when we make a clone. So we need
-         * to ignore it in equals for the transform
-         * tests to pass.
-         */
-        if (this == obj) {
-            return true;
-        }
-        if (obj == null || obj.getClass() != getClass()) {
-            return false;
-        }
-        UnresolvedStar other = (UnresolvedStar) obj;
-        return Objects.equals(qualifier, other.qualifier);
+    protected boolean innerEquals(Object o) {
+        var other = (UnresolvedStar) o;
+        return super.innerEquals(other) && Objects.equals(qualifier, other.qualifier);
     }
 
     private String message() {

x-pack/plugin/esql/src/main/java/org/elasticsearch/xpack/esql/expression/UnresolvedNamePattern.java

@@ -98,20 +98,15 @@ public Nullability nullable() {
     }
 
     @Override
-    public boolean equals(Object o) {
-        if (this == o) {
-            return true;
-        }
-        if (o == null || getClass() != o.getClass() || super.equals(o) == false) {
-            return false;
-        }
-        UnresolvedNamePattern that = (UnresolvedNamePattern) o;
-        return Objects.equals(pattern, that.pattern);
+    @SuppressWarnings("checkstyle:EqualsHashCode")// equals is implemented in parent. See innerEquals instead
+    public int hashCode() {
+        return Objects.hash(super.hashCode(), pattern);
     }
 
     @Override
-    public int hashCode() {
-        return Objects.hash(super.hashCode(), pattern);
+    protected boolean innerEquals(Object o) {
+        var other = (UnresolvedNamePattern) o;
+        return super.innerEquals(other) && Objects.equals(pattern, other.pattern);
     }
 
     @Override

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

@@ -163,20 +163,15 @@ public boolean hasCustomMessage() {
     }
 
     @Override
-    public boolean equals(Object o) {
-        if (this == o) {
-            return true;
-        }
-        if (o == null || getClass() != o.getClass() || super.equals(o) == false) {
-            return false;
-        }
-        UnsupportedAttribute that = (UnsupportedAttribute) o;
-        return hasCustomMessage == that.hasCustomMessage && Objects.equals(message, that.message);
+    @SuppressWarnings("checkstyle:EqualsHashCode")// equals is implemented in parent. See innerEquals instead
+    public int hashCode() {
+        return Objects.hash(super.hashCode(), message, hasCustomMessage);
     }
 
     @Override
-    public int hashCode() {
-        return Objects.hash(super.hashCode(), message, hasCustomMessage);
+    protected boolean innerEquals(Object o) {
+        var other = (UnsupportedAttribute) o;
+        return super.innerEquals(other) && hasCustomMessage == other.hasCustomMessage && Objects.equals(message, other.message);
     }
 
     @Override