Fix for GRAILS-4981 "findBy in validation constraint causes error if …

…another instance is associated"

grails/src/java/org/codehaus/groovy/grails/orm/hibernate/validation/HibernateDomainClassValidator.java

@@ -18,6 +18,8 @@
 import org.codehaus.groovy.grails.orm.hibernate.cfg.GrailsHibernateUtil;
 import org.codehaus.groovy.grails.validation.GrailsDomainClassValidator;
 import org.hibernate.SessionFactory;
+import org.hibernate.FlushMode;
+import org.hibernate.classic.Session;
 import org.hibernate.collection.PersistentCollection;
 import org.springframework.beans.BeanWrapper;
 import org.springframework.beans.BeansException;
@@ -49,6 +51,26 @@ protected Object initialValue() {
         }
     };
     private ApplicationContext applicationContext;
+    private SessionFactory sessionFactory;
+
+    @Override
+    public void validate(Object obj, Errors errors, boolean cascade) {
+        final Session session = sessionFactory.getCurrentSession();
+        FlushMode previousMode = null;
+        try {
+            if(session!=null) {
+                previousMode = session.getFlushMode();
+                session.setFlushMode(FlushMode.MANUAL);
+            }
+
+            super.validate(obj, errors, cascade);
+        }
+        finally {
+            if(session!=null && previousMode!=null) {
+                session.setFlushMode(previousMode);
+            }
+        }
+    }
 
     /**
      * Overrides the default behaviour and first checks if a PersistentCollection instance has been initialised using the
@@ -109,5 +131,13 @@ protected void postValidate(Object obj, Errors errors) {
 
     public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
         this.applicationContext = applicationContext;
+        if(applicationContext!=null) {
+            try {
+                this.sessionFactory = applicationContext.getBean("sessionFactory", SessionFactory.class);
+            }
+            catch (BeansException e) {
+                // no session factory, continue
+            }
+        }
     }
 }

grails/src/test/org/codehaus/groovy/grails/orm/hibernate/CustomValidatorAndDynamicFinderTests.groovy

@@ -0,0 +1,45 @@
+package org.codehaus.groovy.grails.orm.hibernate
+
+import org.hibernate.FlushMode
+
+/**
+ * @author Graeme Rocher
+ * @since 1.1
+ */
+
+public class CustomValidatorAndDynamicFinderTests extends AbstractGrailsHibernateTests{
+
+    protected void onSetUp() {
+        gcl.parseClass('''
+import grails.persistence.*
+
+@Entity
+class Foo {
+	String name
+
+	Foo partner
+
+	static constraints = {
+		name(validator: {name, foo ->
+			Foo similarFoo = Foo.findByNameIlike(name)
+			if (similarFoo && similarFoo.id != foo.id) return ['similar']
+		})
+	}
+}
+''')
+    }
+
+    // test for GRAILS-4981
+    void testCustomValidatorWithFinder() {
+        session.setFlushMode(FlushMode.AUTO) 
+        def Foo = ga.getDomainClass("Foo").clazz
+
+        def foo = Foo.newInstance(name: 'partner1')
+        assert foo.save()
+        def partner = Foo.newInstance(name: 'partner2')
+        assert partner.save()
+        foo.partner = partner
+        assert foo.save()
+
+    }
+}