When changing from a non-primary index to a primary index, the dropped index isn't named PRIMARY

lib/Doctrine/DBAL/Platforms/MySqlPlatform.php

@@ -623,6 +623,15 @@ class MySqlPlatform extends AbstractPlatform
                 }
             }
         }
+        foreach ($diff->changedIndexes as $changedKey => $changedIndex) {
+            if ($changedIndex->isPrimary() && $changedKey != 'PRIMARY') {
+                $index = $diff->changedIndexes[$changedKey];
+                $index = new Index($changedKey, $index->getColumns(), $index->isUnique(), false);
+                $diff->removedIndexes[$changedKey] = $index;
+                $diff->addedIndexes['PRIMARY'] = $diff->changedIndexes[$changedKey];
+                unset($diff->changedIndexes[$changedKey]);
+            }
+        }
 
         $sql = array_merge($sql, parent::getPreAlterTableIndexForeignKeySQL($diff));
 

tests/Doctrine/Tests/DBAL/Platforms/MySqlPlatformTest.php

@@ -343,4 +343,17 @@ class MySqlPlatformTest extends AbstractPlatformTestCase
             "ALTER TABLE foo ADD id INT AUTO_INCREMENT NOT NULL, ADD PRIMARY KEY (id)",
         ), $sql);
     }
+
+    public function testNamedPrimaryKey()
+    {
+        $diff = new TableDiff('mytable');
+        $diff->changedIndexes['foo_index'] = new Index('foo_index', array('foo'), true, true);
+
+        $sql = $this->_platform->getAlterTableSQL($diff);
+
+        $this->assertEquals(array(
+	    "DROP INDEX foo_index ON mytable",
+            "ALTER TABLE mytable ADD PRIMARY KEY (foo)",
+        ), $sql);
+    }
 }