Merge branch '2.8' into 3.0

* 2.8:
  [HttpFoundation] Fix UPSERT for PgSql >= 9.5
  [Form] fixed DateTime transformers
  [PropertyAccess][DX] Enhance exception that say that some methods are missing if they don't
  [Form] fixed EntityType test with query_builder option

Conflicts:
	src/Symfony/Component/Form/Extension/Core/DataTransformer/DateTimeToStringTransformer.php
	src/Symfony/Component/Form/Extension/Core/DataTransformer/DateTimeToTimestampTransformer.php

Author: nicolas-grekas

HttpFoundation/DbalSessionHandler.php

@@ -243,7 +243,7 @@ private function getMergeSql()
                 return "INSERT OR REPLACE INTO $this->table ($this->idCol, $this->dataCol, $this->timeCol) VALUES (:id, :data, :time)";
             case 'postgresql' === $platform && version_compare($this->con->getServerVersion(), '9.5', '>='):
                 return "INSERT INTO $this->table ($this->idCol, $this->dataCol, $this->timeCol) VALUES (:id, :data, :time) ".
-                    "ON CONFLICT ($this->idCol) DO UPDATE SET ($this->dataCol, $this->timeCol) = (:data, :time) WHERE $this->idCol = :id";
+                    "ON CONFLICT ($this->idCol) DO UPDATE SET ($this->dataCol, $this->timeCol) = (EXCLUDED.$this->dataCol, EXCLUDED.$this->timeCol)";
         }
     }
 }

Tests/Form/Type/EntityTypeTest.php

@@ -209,8 +209,13 @@ public function testConfigureQueryBuilderWithClosureReturningNonQueryBuilder()
         $field->submit('2');
     }
 
-    public function testConfigureQueryBuilderWithClosureReturningNull()
+    public function testConfigureQueryBuilderWithClosureReturningNullUseDefault()
     {
+        $entity1 = new SingleIntIdEntity(1, 'Foo');
+        $entity2 = new SingleIntIdEntity(2, 'Bar');
+
+        $this->persist(array($entity1, $entity2));
+
         $field = $this->factory->createNamed('name', 'Symfony\Bridge\Doctrine\Form\Type\EntityType', null, array(
             'em' => 'default',
             'class' => self::SINGLE_IDENT_CLASS,
@@ -219,7 +224,7 @@ public function testConfigureQueryBuilderWithClosureReturningNull()
             },
         ));
 
-        $this->assertEquals(array(), $field->createView()->vars['choices']);
+        $this->assertEquals(array(1 => new ChoiceView($entity1, '1', 'Foo'), 2 => new ChoiceView($entity2, '2', 'Bar')), $field->createView()->vars['choices']);
     }
 
     public function testSetDataSingleNull()