added a test case that shows #110 is fixed, fix for #110 based on 7.0.x branch

Author: billgonemad

grails-datastore-gorm-hibernate5/src/main/groovy/org/grails/orm/hibernate/AbstractHibernateGormInstanceApi.groovy

@@ -390,7 +390,7 @@ abstract class AbstractHibernateGormInstanceApi<D> extends GormInstanceApi<D> {
         setObjectToReadOnly target
         if (entity) {
             for (Association association in entity.associations) {
-                if (association instanceof ToOne) {
+                if (association instanceof ToOne && !association instanceof Embedded) {
                     if(proxyHandler.isInitialized(target, association.name)) {
                         def bean = new BeanWrapperImpl(target)
                         def propertyValue = bean.getPropertyValue(association.name)

grails-datastore-gorm-hibernate5/src/test/groovy/grails/gorm/tests/validation/EmbeddedWithValidationExceptionSpec.groovy

@@ -0,0 +1,54 @@
+package grails.gorm.tests.validation
+
+import grails.gorm.annotation.Entity
+import grails.gorm.tests.GormDatastoreSpec
+import grails.gorm.transactions.Rollback
+import grails.validation.ValidationException
+import spock.lang.Issue
+
+class EmbeddedWithValidationExceptionSpec extends GormDatastoreSpec {
+    @Override
+    List getDomainClasses() {
+        return [DomainWithEmbedded]
+    }
+
+    @Rollback
+    @Issue("https://github.com/grails/gorm-hibernate5/issues/110")
+    void "test validation exception with embedded in domain"() {
+        when:
+        new DomainWithEmbedded(
+                foo: 'not valid',
+                myEmbedded: new MyEmbedded(
+                        a: 1,
+                        b: 'foo'
+                )
+        ).save(failOnError: true)
+
+        then:
+        thrown(ValidationException)
+    }
+}
+
+@Entity
+class DomainWithEmbedded {
+    MyEmbedded myEmbedded
+    String foo
+
+    static embedded = ['myEmbedded']
+
+    static constraints = {
+        foo(validator: { val, self ->
+            return 'not.valid.foo'
+        })
+    }
+}
+
+class MyEmbedded {
+    Integer a
+    String b
+
+    static constraints = {
+        a(nullable: true)
+        b(nullalbe: true)
+    }
+}