Speedup equals (#126394) (#128949)

(cherry picked from commit e95397c)

Author: idegtiarenko

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

@@ -112,18 +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 (super.equals(obj)) {
-            Attribute other = (Attribute) obj;
-            return Objects.equals(nullability, other.nullability);
-        }
-
-        return false;
+    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

@@ -60,20 +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/EntryExpression.java

@@ -99,7 +99,6 @@ public boolean equals(Object obj) {
         if (obj == null || getClass() != obj.getClass()) {
             return false;
         }
-
         EntryExpression other = (EntryExpression) obj;
         return Objects.equals(key, other.key) && Objects.equals(value, other.value);
     }

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

@@ -223,15 +223,15 @@ public Attribute withDataType(DataType type) {
     }
 
     @Override
+    @SuppressWarnings("checkstyle:EqualsHashCode")// equals is implemented in parent. See innerEquals instead
     public int hashCode() {
         return Objects.hash(super.hashCode(), parentName, field);
     }
 
     @Override
-    public boolean equals(Object obj) {
-        return super.equals(obj)
-            && Objects.equals(parentName, ((FieldAttribute) obj).parentName)
-            && Objects.equals(field, ((FieldAttribute) obj).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

@@ -173,16 +173,14 @@ public static boolean isSupported(String name) {
     }
 
     @Override
-    public boolean equals(Object obj) {
-        if (false == super.equals(obj)) {
-            return false;
-        }
-        MetadataAttribute other = (MetadataAttribute) obj;
-        return searchable == other.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

@@ -61,17 +61,26 @@ public int hashCode() {
         return Objects.hash(super.hashCode(), name, synthetic);
     }
 
+    /**
+     * Polymorphic equality is a pain and are likely slower than a regular ones.
+     * This equals shortcuts `this == o` and type checks (important when we expect only a few non-equal objects).
+     * Here equals is final to ensure we are not duplicating 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;
         }
+        return innerEquals(o);
+    }
 
-        NamedExpression other = (NamedExpression) obj;
-        return Objects.equals(synthetic, other.synthetic)
+    protected boolean innerEquals(Object o) {
+        var other = (NamedExpression) o;
+        return synthetic == other.synthetic
             /*
              * It is important that the line below be `name`
              * and not `name()` because subclasses might override

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

@@ -34,12 +34,14 @@ public DataType dataType() {
     }
 
     @Override
+    @SuppressWarnings("checkstyle:EqualsHashCode")// equals is implemented in parent. See innerEquals instead
     public int hashCode() {
         return Objects.hash(super.hashCode(), dataType);
     }
 
     @Override
-    public boolean equals(Object obj) {
-        return super.equals(obj) && Objects.equals(dataType, ((TypedAttribute) obj).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

@@ -21,8 +21,8 @@
 
 // unfortunately we can't use UnresolvedNamedExpression
 public class UnresolvedAttribute extends Attribute implements Unresolvable {
-    private final String unresolvedMsg;
     private final boolean customMessage;
+    private final String unresolvedMsg;
     private final Object resolutionMetadata;
 
     public UnresolvedAttribute(Source source, String name) {
@@ -119,16 +119,16 @@ public static String errorMessage(String name, List<String> potentialMatches) {
     }
 
     @Override
+    @SuppressWarnings("checkstyle:EqualsHashCode")// equals is implemented in parent. See innerEquals instead
     public int hashCode() {
         return Objects.hash(super.hashCode(), resolutionMetadata, unresolvedMsg);
     }
 
     @Override
-    public boolean equals(Object obj) {
-        if (super.equals(obj)) {
-            UnresolvedAttribute ua = (UnresolvedAttribute) obj;
-            return Objects.equals(resolutionMetadata, ua.resolutionMetadata) && Objects.equals(unresolvedMsg, ua.unresolvedMsg);
-        }
-        return false;
+    protected boolean innerEquals(Object o) {
+        var other = (UnresolvedAttribute) o;
+        return super.innerEquals(other)
+            && Objects.equals(resolutionMetadata, other.resolutionMetadata)
+            && Objects.equals(unresolvedMsg, other.unresolvedMsg);
     }
 }

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

@@ -57,25 +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 (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

@@ -98,17 +98,15 @@ public Nullability nullable() {
     }
 
     @Override
+    @SuppressWarnings("checkstyle:EqualsHashCode")// equals is implemented in parent. See innerEquals instead
     public int hashCode() {
         return Objects.hash(super.hashCode(), pattern);
     }
 
     @Override
-    public boolean equals(Object obj) {
-        if (super.equals(obj)) {
-            UnresolvedNamePattern ua = (UnresolvedNamePattern) obj;
-            return Objects.equals(pattern, ua.pattern);
-        }
-        return false;
+    protected boolean innerEquals(Object o) {
+        var other = (UnresolvedNamePattern) o;
+        return super.innerEquals(other) && Objects.equals(pattern, other.pattern);
     }
 
     @Override