fix "If-Equal" header predicate for new different from predicate for …

…existing

* causing that e.g. the existing Json did not contain "thingId" whereas the new one did

internal/utils/conditional-headers/src/main/java/org/eclipse/ditto/internal/utils/headers/conditional/IfEqualPreconditionHeader.java

@@ -23,6 +23,8 @@
 import javax.annotation.concurrent.Immutable;
 
 import org.eclipse.ditto.base.model.entity.Entity;
+import org.eclipse.ditto.base.model.entity.id.EntityId;
+import org.eclipse.ditto.base.model.entity.type.EntityType;
 import org.eclipse.ditto.base.model.headers.DittoHeaderDefinition;
 import org.eclipse.ditto.base.model.headers.IfEqual;
 import org.eclipse.ditto.base.model.json.FieldType;
@@ -52,6 +54,9 @@ public final class IfEqualPreconditionHeader<C extends Command<?>> implements Pr
 
     private static final String IF_EQUAL_KEY = DittoHeaderDefinition.IF_EQUAL.getKey();
 
+    private static final EntityType POLICY_ENTITY_TYPE = EntityType.of("policy");
+    private static final EntityType THING_ENTITY_TYPE = EntityType.of("thing");
+
     private final C command;
     private final IfEqual ifEqual;
     private final ConditionalHeadersValidator.ValidationSettings validationSettings;
@@ -132,14 +137,18 @@ private Boolean meetsConditionForModifyCommand(final Entity<?> entity,
 
         return withOptionalEntity.getEntity()
                 .map(newValue -> {
-                    final Predicate<JsonField> fieldPredicate = calculatePredicate(command.getResourcePath());
+                    final Predicate<JsonField> fieldPredicate = calculatePredicate(command.getResourcePath(),
+                            entity.getEntityId().map(EntityId::getEntityType).orElse(null));
                     final Optional<JsonValue> previousValue =
                             entity.toJson(JsonSchemaVersion.LATEST, fieldPredicate)
                                     .getValue(command.getResourcePath());
                     final JsonValue adjustedNewValue;
                     if (newValue.isObject()) {
                         adjustedNewValue = newValue.asObject()
-                                .filter(calculatePredicateForNew(command.getResourcePath()));
+                                .filter(calculatePredicateForNew(
+                                        command.getResourcePath(),
+                                        entity.getEntityId().map(EntityId::getEntityType).orElse(null)
+                                ));
                     } else {
                         adjustedNewValue = newValue;
                     }
@@ -160,7 +169,10 @@ private Boolean meetsConditionForMergeCommand(final Entity<?> entity,
                         if (command.getResourcePath().isEmpty()) {
                             newObject = newValue.asObject()
                                     .stream()
-                                    .filter(calculatePredicateForNew(command.getResourcePath()))
+                                    .filter(calculatePredicateForNew(
+                                            command.getResourcePath(),
+                                            entity.getEntityId().map(EntityId::getEntityType).orElse(null)
+                                    ))
                                     .collect(JsonCollectors.fieldsToObject());
                         } else {
                             newObject = newValue.asObject();
@@ -240,7 +252,8 @@ private C adjustMergeCommandByOnlyKeepingChanges(final C command,
 
         return withOptionalEntity.getEntity()
                 .map(newValue -> {
-                    final Predicate<JsonField> fieldPredicate = calculatePredicate(command.getResourcePath());
+                    final Predicate<JsonField> fieldPredicate = calculatePredicate(command.getResourcePath(),
+                            entity.getEntityId().map(EntityId::getEntityType).orElse(null));
                     final JsonValue oldValue = entity.toJson(JsonSchemaVersion.LATEST, fieldPredicate)
                             .getValue(command.getResourcePath()).orElse(null);
                     if (null == oldValue) {
@@ -259,22 +272,31 @@ private C adjustMergeCommandByOnlyKeepingChanges(final C command,
                 .orElse(command);
     }
 
-    private static Predicate<JsonField> calculatePredicate(final JsonPointer resourcePath) {
+    private static Predicate<JsonField> calculatePredicate(final JsonPointer resourcePath,
+            @Nullable final EntityType entityType
+    ) {
         if (resourcePath.isEmpty()) {
             return FieldType.notHidden()
-                    .and(Predicate.not(jsonField -> jsonField.getKey().equals(JsonKey.of("thingId"))))
-                    .and(Predicate.not(jsonField -> jsonField.getKey().equals(JsonKey.of("policyId"))));
+                    .and(Predicate.not(jsonField ->
+                            THING_ENTITY_TYPE.equals(entityType) && jsonField.getKey().equals(JsonKey.of("thingId"))
+                    ))
+                    .and(Predicate.not(jsonField ->
+                            POLICY_ENTITY_TYPE.equals(entityType) && jsonField.getKey().equals(JsonKey.of("policyId"))
+                    ));
         } else {
             return FieldType.notHidden();
         }
     }
 
-    private static Predicate<JsonField> calculatePredicateForNew(final JsonPointer resourcePath) {
+    private static Predicate<JsonField> calculatePredicateForNew(final JsonPointer resourcePath,
+            @Nullable final EntityType entityType
+    ) {
         if (resourcePath.isEmpty()) {
-            // filter "special fields" for e.g. on thing level the inline "_policy":
-            return jsonField -> !jsonField.getKeyName().startsWith("_");
+            return calculatePredicate(resourcePath, entityType)
+                    // filter "special fields" for e.g. on thing level the inline "_policy":
+                    .and(jsonField -> !jsonField.getKeyName().startsWith("_"));
         } else {
-            return jsonField -> true;
+            return calculatePredicate(resourcePath, entityType);
         }
     }