Compare entity and property models by identity (plan item 2.7)

core/src/main/java/dev/morphia/mapping/codec/pojo/EntityModel.java

@@ -61,7 +61,7 @@
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
 import static dev.morphia.mapping.PropertyDiscovery.FIELDS;
 import static java.lang.String.format;
 import static java.util.Arrays.stream;
 import static java.util.Collections.emptyList;
@@ -528,33 +528,6 @@
         }
     }
 
-    @Override
-    public int hashCode() {
-        return Objects.hash(annotations, propertyModelsByName, propertyModelsByMappedName, creatorFactory,
-                discriminatorEnabled, discriminatorKey(), discriminator(), getType(), collectionName(), listeners);
-    }
-
-    @Override
-    public boolean equals(Object o) {
-        if (this == o) {
-            return true;
-        }
-        if (!(o instanceof EntityModel)) {
-            return false;
-        }
-        final EntityModel that = (EntityModel) o;
-        return discriminatorEnabled == that.discriminatorEnabled
-                && Objects.equals(annotations, that.annotations)
-                && Objects.equals(propertyModelsByName, that.propertyModelsByName)
-                && Objects.equals(propertyModelsByMappedName, that.propertyModelsByMappedName)
-                && Objects.equals(creatorFactory, that.creatorFactory)
-                && Objects.equals(discriminatorKey(), that.discriminatorKey())
-                && Objects.equals(discriminator(), that.discriminator())
-                && Objects.equals(getType(), that.getType())
-                && Objects.equals(collectionName(), that.collectionName())
-                && Objects.equals(listeners, that.listeners);
-    }
-
     @Override
     public String toString() {
         String properties = propertyModelsByName.values().stream()

core/src/main/java/dev/morphia/mapping/codec/pojo/PropertyModel.java

@@ -23,7 +23,6 @@
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
-import java.util.Objects;
 import java.util.Set;
 import java.util.StringJoiner;
 
@@ -174,12 +173,6 @@ Codec<?> getCodec() {
         return codec;
     }
 
-    @Override
-    public int hashCode() {
-        return Objects.hash(getName(), getTypeData(), getMappedName(), codec, getAccessor(), serialization,
-                annotationMap.values(), getNormalizedType());
-    }
-
     /**
      * @param document the Document get the value from
      * @return the value from first mapping of this field
@@ -295,23 +288,6 @@ public boolean hasAnnotation(Class<? extends Annotation> type) {
         return annotationMap.containsKey(type);
     }
 
-    @Override
-    public boolean equals(Object o) {
-        if (this == o) {
-            return true;
-        }
-        if (!(o instanceof PropertyModel that)) {
-            return false;
-        }
-        return getName().equals(that.getName())
-                && getTypeData().equals(that.getTypeData())
-                && getMappedName().equals(that.getMappedName())
-                && Objects.equals(codec, that.codec)
-                && getAccessor().equals(that.getAccessor())
-                && serialization.equals(that.serialization)
-                && Objects.equals(getNormalizedType(), that.getNormalizedType());
-    }
-
     /**
      * @param datastore
      * @return the custom codec to use if set or null

core/src/test/java/dev/morphia/test/mapping/codec/harness/CodecHarnessTest.java

@@ -26,6 +26,7 @@
 import dev.morphia.mapping.DiscriminatorFunction;
 import dev.morphia.mapping.MapperType;
 import dev.morphia.mapping.codec.pojo.EntityModel;
+import dev.morphia.mapping.codec.pojo.PropertyModel;
 import dev.morphia.mapping.codec.pojo.critter.CritterEntityModel;
 import dev.morphia.test.mapping.codec.harness.models.HarnessArrays;
 import dev.morphia.test.mapping.codec.harness.models.HarnessCallbackCircle;
@@ -206,6 +207,25 @@ private static void assertCallbacks(String message, HarnessCallbackShape shape,
                 message + ": @PrePersist, @PostPersist, @PreLoad, @PostLoad counts");
     }
 
+    @Test
+    void modelHashesAreStableAcrossEncoding() {
+        for (MapperType mapper : MapperType.values()) {
+            MorphiaDatastore datastore = datastore(Variant.DEFAULTS, mapper);
+            EntityModel model = datastore.getMapper().getEntityModel(HarnessScalars.class);
+            Set<EntityModel> models = new HashSet<>(Set.of(model));
+            Set<PropertyModel> properties = new HashSet<>(model.getProperties());
+
+            // encoding specializes each property's codec, which used to change its hash
+            Codec<HarnessScalars> codec = codec(datastore, HarnessScalars.class);
+            decode(codec, encode(codec, HarnessScalars.sample(), COLLECTIBLE));
+
+            assertTrue(models.contains(model), mapper + ": the model's hash changed");
+            for (PropertyModel property : model.getProperties()) {
+                assertTrue(properties.contains(property), mapper + ": the hash of " + property.getName() + " changed");
+            }
+        }
+    }
+
     @Test
     void readsLoadOnlyProperties() {
         // @LoadOnly values are never written, so the fixtures can't show that they are read

design/mapping-game-plan.md

@@ -174,7 +174,7 @@ structural item covers are moved to that item (see Phases 4 and 5).
 - Write the test first (`List<Shape>`, where `Shape` has `@PrePersist`).
 - Fix it by delegating subtypes *before* running callbacks in `LifecycleEncoder`/`LifecycleDecoder`.
 
-### 2.7 `PropertyModel.hashCode` includes the lazy codec (D5)
+### ~~2.7 `PropertyModel.hashCode` includes the lazy codec (D5)~~
 - Delete the `equals`/`hashCode` overrides on `EntityModel` and `PropertyModel`, so both compare by identity.
   This also removes the deep `equals` cost on `CopyOnWriteArraySet.add` and in `EntityEncoder`.
 - Audit tests for any that rely on structural equality.