[DBAL-586] Fix failures introduced by PR and adjust code.

lib/Doctrine/DBAL/Platforms/MySqlPlatform.php

@@ -623,15 +623,6 @@ 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

@@ -296,6 +296,28 @@ class MySqlPlatformTest extends AbstractPlatformTestCase
         $this->assertEquals('LONGBLOB', $this->_platform->getBlobTypeDeclarationSQL(array()));
     }
 
+    /**
+     * @group DBAL-400
+     */
+    public function testAlterTableAddPrimaryKey()
+    {
+        $table = new Table('alter_table_add_pk');
+        $table->addColumn('id', 'integer');
+        $table->addColumn('foo', 'integer');
+        $table->addIndex(array('id'), 'idx_id');
+
+        $comparator = new Comparator();
+        $diffTable  = clone $table;
+
+        $diffTable->dropIndex('idx_id');
+        $diffTable->setPrimaryKey(array('id'));
+
+        $this->assertEquals(
+            array('DROP INDEX idx_id ON alter_table_add_pk', 'ALTER TABLE alter_table_add_pk ADD PRIMARY KEY (id)'),
+            $this->_platform->getAlterTableSQL($comparator->diffTable($table, $diffTable))
+        );
+    }
+
     /**
      * @group DBAL-464
      */
@@ -352,7 +374,7 @@ class MySqlPlatformTest extends AbstractPlatformTestCase
         $sql = $this->_platform->getAlterTableSQL($diff);
 
         $this->assertEquals(array(
-	    "DROP INDEX foo_index ON mytable",
+	        "ALTER TABLE mytable DROP PRIMARY KEY",
             "ALTER TABLE mytable ADD PRIMARY KEY (foo)",
         ), $sql);
     }