#1263 Fix issue with UniqueConstraint (#1276)

Fetch identifier using ProxyHandler if the association is a proxy.

Author: puneetbehl

grails-datastore-gorm-test/src/test/groovy/org/grails/datastore/gorm/validation/UniqueConstraintSpec.groovy

@@ -54,6 +54,30 @@ class UniqueConstraintSpec extends Specification {
 
     }
 
+    void "test unique constraint checks parent field"() {
+
+        setup:
+        Organization organization = new Organization(name: "Test Org")
+        organization.defaultChannel.organization = organization
+        organization.addToChannels(name: "Foo")
+        organization.addToChannels(name: "Bar")
+        organization.save(flush: true, failOnError: true)
+        datastore.currentSession.clear()
+
+        when: "we change the channel name to an existing channel name in the organization"
+        Channel channel = Channel.findByName("Bar")
+        channel.name = "Foo"
+
+        then:
+        !channel.validate()
+        channel.hasErrors()
+        channel.errors.getFieldError('name').code == 'unique'
+
+        cleanup:
+        Channel.deleteAll()
+        Organization.deleteAll(organization)
+    }
+
     void 'unique constraint works with parent/child/child'() {
         given: 'an existing channel'
         def testOrg = new Organization(name: 'Test 1')
@@ -120,7 +144,7 @@ class UniqueConstraintSpec extends Specification {
 
 
 @Entity
-abstract class Channel {
+class Channel {
 
     String name
     static belongsTo = [organization: Organization]
@@ -165,4 +189,5 @@ class Organization {
     DefaultChannel defaultChannel = new DefaultChannel()
 
     static hasOne = [defaultChannel: DefaultChannel]
+    static hasMany = [channels: Channel]
 }

grails-datastore-gorm/src/main/groovy/org/grails/datastore/gorm/validation/constraints/builtin/UniqueConstraint.groovy

@@ -9,6 +9,7 @@ import org.grails.datastore.mapping.model.PersistentEntity
 import org.grails.datastore.mapping.model.PersistentProperty
 import org.grails.datastore.mapping.model.types.Association
 import org.grails.datastore.mapping.model.types.ToOne
+import org.grails.datastore.mapping.proxy.ProxyHandler
 import org.grails.datastore.mapping.reflect.EntityReflector
 import org.springframework.context.MessageSource
 import org.springframework.validation.Errors
@@ -103,6 +104,7 @@ class UniqueConstraint extends AbstractConstraint {
 
         if (constraintParameter) {
             boolean shouldValidate = true
+            final ProxyHandler proxyHandler = targetEntity.getMappingContext().proxyHandler
             detachedCriteria = detachedCriteria.build {
                 eq(constraintPropertyName, propertyValue)
                 if (!group.isEmpty()) {
@@ -113,7 +115,12 @@ class UniqueConstraint extends AbstractConstraint {
                             PersistentProperty associated = targetEntity.getPropertyByName(propName)
                             if (associated instanceof ToOne) {
                                 // We are merely verifying that the object is not transient here
-                                def associationId = ((Association) associated).getAssociatedEntity().getReflector().getIdentifier(value)
+                                def associationId
+                                if (proxyHandler.isProxy(value)) {
+                                    associationId = proxyHandler.getIdentifier(value)
+                                } else {
+                                    associationId = ((Association) associated).getAssociatedEntity().getReflector().getIdentifier(value)
+                                }
                                 if (associationId == null) {
                                     // no need to validate since this group association is unsaved
                                     shouldValidate = false