Fix DisableCreateTable for MigrationSet instances.

Previously the DisableCreateTable setting was always being read from the
global `migSet` instance. This meant that setting
`ms.DisableCreateTable` on a given `var ms MigrationSet` instance had no
effect.

This commit fixes that bug, and adds a test to confirm the fix.
Regardless of the global `migSet.DisableCreateTable` value,
`ms.getMigrationDbMap()` will always read from `ms.DisableCreateTable`.

Author: peterldowns

migrate.go

@@ -819,7 +819,7 @@ Check https://github.com/go-sql-driver/mysql#parsetime for more info.`)
 		table.ColMap("Id").SetMaxSize(4000)
 	}
 
-	if migSet.DisableCreateTable {
+	if ms.DisableCreateTable {
 		return dbMap, nil
 	}
 

migrate_test.go

@@ -758,3 +758,51 @@ func (s *SqliteMigrateSuite) TestGetMigrationDbMapWithDisableCreateTable(c *C) {
 	_, err := migSet.getMigrationDbMap(s.Db, "postgres")
 	c.Assert(err, IsNil)
 }
+
+// If ms.DisableCreateTable == true, then the the migrations table should not be
+// created, regardless of the global migSet.DisableCreateTable setting.
+func (s *SqliteMigrateSuite) TestGetMigrationObjDbMapWithDisableCreateTableTrue(c *C) {
+	SetDisableCreateTable(false)
+	ms := MigrationSet{
+		DisableCreateTable: true,
+		TableName:          "silly_example_table",
+	}
+	c.Assert(migSet.DisableCreateTable, Equals, false)
+	c.Assert(ms.DisableCreateTable, Equals, true)
+
+	dbMap, err := ms.getMigrationDbMap(s.Db, "sqlite3")
+	c.Assert(err, IsNil)
+	c.Assert(dbMap, NotNil)
+
+	tableNameIfExists, err := s.DbMap.SelectNullStr(
+		"SELECT name FROM sqlite_master WHERE type='table' AND name=$1",
+		ms.TableName,
+	)
+	c.Assert(err, IsNil)
+	c.Assert(tableNameIfExists.Valid, Equals, false)
+}
+
+// If ms.DisableCreateTable == false, then the the migrations table should not be
+// created, regardless of the global migSet.DisableCreateTable setting.
+func (s *SqliteMigrateSuite) TestGetMigrationObjDbMapWithDisableCreateTableFalse(c *C) {
+	SetDisableCreateTable(true)
+	defer SetDisableCreateTable(false) // reset the global state when the test ends.
+	ms := MigrationSet{
+		DisableCreateTable: false,
+		TableName:          "silly_example_table",
+	}
+	c.Assert(migSet.DisableCreateTable, Equals, true)
+	c.Assert(ms.DisableCreateTable, Equals, false)
+
+	dbMap, err := ms.getMigrationDbMap(s.Db, "sqlite3")
+	c.Assert(err, IsNil)
+	c.Assert(dbMap, NotNil)
+
+	tableNameIfExists, err := s.DbMap.SelectNullStr(
+		"SELECT name FROM sqlite_master WHERE type='table' AND name=$1",
+		ms.TableName,
+	)
+	c.Assert(err, IsNil)
+	c.Assert(tableNameIfExists.Valid, Equals, true)
+	c.Assert(tableNameIfExists.String, Equals, ms.TableName)
+}