[pigeon] Optimize data class equality and hashing in Dart, Kotlin, java, and Swift, adds equality in other languages (#11140)

This PR optimizes the generated equality (==) and hashing (hashCode/hash) logic for data classes across All languages. These have been bothering me for a while, and I wanted to break out a new pr before the NI code is in review.

Author: tarrinneal

packages/pigeon/CHANGELOG.md

@@ -1,3 +1,9 @@
+## 26.3.0
+
+* Optimizes and improves data class equality and hashing.
+* Changes hashing and equality methods to behave consistently across platforms.
+* Adds equality methods to previously unsupported languages.
+
 ## 26.2.3
 
 * Produces a helpful error message when a method return type is missing or an

packages/pigeon/example/app/android/app/src/main/java/io/flutter/plugins/Messages.java

@@ -19,14 +19,171 @@
 import java.lang.annotation.Target;
 import java.nio.ByteBuffer;
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.Collections;
 import java.util.List;
 import java.util.Map;
-import java.util.Objects;
 
 /** Generated class from Pigeon. */
 @SuppressWarnings({"unused", "unchecked", "CodeBlock2Expr", "RedundantSuppression", "serial"})
 public class Messages {
+  static boolean pigeonDoubleEquals(double a, double b) {
+    // Normalize -0.0 to 0.0 and handle NaN equality.
+    return (a == 0.0 ? 0.0 : a) == (b == 0.0 ? 0.0 : b) || (Double.isNaN(a) && Double.isNaN(b));
+  }
+
+  static boolean pigeonFloatEquals(float a, float b) {
+    // Normalize -0.0 to 0.0 and handle NaN equality.
+    return (a == 0.0f ? 0.0f : a) == (b == 0.0f ? 0.0f : b) || (Float.isNaN(a) && Float.isNaN(b));
+  }
+
+  static int pigeonDoubleHashCode(double d) {
+    // Normalize -0.0 to 0.0 and handle NaN to ensure consistent hash codes.
+    if (d == 0.0) {
+      d = 0.0;
+    }
+    long bits = Double.doubleToLongBits(d);
+    return (int) (bits ^ (bits >>> 32));
+  }
+
+  static int pigeonFloatHashCode(float f) {
+    // Normalize -0.0 to 0.0 and handle NaN to ensure consistent hash codes.
+    if (f == 0.0f) {
+      f = 0.0f;
+    }
+    return Float.floatToIntBits(f);
+  }
+
+  static boolean pigeonDeepEquals(Object a, Object b) {
+    if (a == b) {
+      return true;
+    }
+    if (a == null || b == null) {
+      return false;
+    }
+    if (a instanceof byte[] && b instanceof byte[]) {
+      return Arrays.equals((byte[]) a, (byte[]) b);
+    }
+    if (a instanceof int[] && b instanceof int[]) {
+      return Arrays.equals((int[]) a, (int[]) b);
+    }
+    if (a instanceof long[] && b instanceof long[]) {
+      return Arrays.equals((long[]) a, (long[]) b);
+    }
+    if (a instanceof double[] && b instanceof double[]) {
+      double[] da = (double[]) a;
+      double[] db = (double[]) b;
+      if (da.length != db.length) {
+        return false;
+      }
+      for (int i = 0; i < da.length; i++) {
+        if (!pigeonDoubleEquals(da[i], db[i])) {
+          return false;
+        }
+      }
+      return true;
+    }
+    if (a instanceof List && b instanceof List) {
+      List<?> listA = (List<?>) a;
+      List<?> listB = (List<?>) b;
+      if (listA.size() != listB.size()) {
+        return false;
+      }
+      for (int i = 0; i < listA.size(); i++) {
+        if (!pigeonDeepEquals(listA.get(i), listB.get(i))) {
+          return false;
+        }
+      }
+      return true;
+    }
+    if (a instanceof Map && b instanceof Map) {
+      Map<?, ?> mapA = (Map<?, ?>) a;
+      Map<?, ?> mapB = (Map<?, ?>) b;
+      if (mapA.size() != mapB.size()) {
+        return false;
+      }
+      for (Map.Entry<?, ?> entryA : mapA.entrySet()) {
+        Object keyA = entryA.getKey();
+        Object valueA = entryA.getValue();
+        boolean found = false;
+        for (Map.Entry<?, ?> entryB : mapB.entrySet()) {
+          Object keyB = entryB.getKey();
+          if (pigeonDeepEquals(keyA, keyB)) {
+            Object valueB = entryB.getValue();
+            if (pigeonDeepEquals(valueA, valueB)) {
+              found = true;
+              break;
+            } else {
+              return false;
+            }
+          }
+        }
+        if (!found) {
+          return false;
+        }
+      }
+      return true;
+    }
+    if (a instanceof Double && b instanceof Double) {
+      return pigeonDoubleEquals((double) a, (double) b);
+    }
+    if (a instanceof Float && b instanceof Float) {
+      return pigeonFloatEquals((float) a, (float) b);
+    }
+    return a.equals(b);
+  }
+
+  static int pigeonDeepHashCode(Object value) {
+    if (value == null) {
+      return 0;
+    }
+    if (value instanceof byte[]) {
+      return Arrays.hashCode((byte[]) value);
+    }
+    if (value instanceof int[]) {
+      return Arrays.hashCode((int[]) value);
+    }
+    if (value instanceof long[]) {
+      return Arrays.hashCode((long[]) value);
+    }
+    if (value instanceof double[]) {
+      double[] da = (double[]) value;
+      int result = 1;
+      for (double d : da) {
+        result = 31 * result + pigeonDoubleHashCode(d);
+      }
+      return result;
+    }
+    if (value instanceof List) {
+      int result = 1;
+      for (Object item : (List<?>) value) {
+        result = 31 * result + pigeonDeepHashCode(item);
+      }
+      return result;
+    }
+    if (value instanceof Map) {
+      int result = 0;
+      for (Map.Entry<?, ?> entry : ((Map<?, ?>) value).entrySet()) {
+        result +=
+            ((pigeonDeepHashCode(entry.getKey()) * 31) ^ pigeonDeepHashCode(entry.getValue()));
+      }
+      return result;
+    }
+    if (value instanceof Object[]) {
+      int result = 1;
+      for (Object item : (Object[]) value) {
+        result = 31 * result + pigeonDeepHashCode(item);
+      }
+      return result;
+    }
+    if (value instanceof Double) {
+      return pigeonDoubleHashCode((double) value);
+    }
+    if (value instanceof Float) {
+      return pigeonFloatHashCode((float) value);
+    }
+    return value.hashCode();
+  }
 
   /** Error class for passing custom error details to Flutter via a thrown PlatformException. */
   public static class FlutterError extends RuntimeException {
@@ -142,15 +299,16 @@ public boolean equals(Object o) {
         return false;
       }
       MessageData that = (MessageData) o;
-      return Objects.equals(name, that.name)
-          && Objects.equals(description, that.description)
-          && code.equals(that.code)
-          && data.equals(that.data);
+      return pigeonDeepEquals(name, that.name)
+          && pigeonDeepEquals(description, that.description)
+          && pigeonDeepEquals(code, that.code)
+          && pigeonDeepEquals(data, that.data);
     }
 
     @Override
     public int hashCode() {
-      return Objects.hash(name, description, code, data);
+      Object[] fields = new Object[] {getClass(), name, description, code, data};
+      return pigeonDeepHashCode(fields);
     }
 
     public static final class Builder {