synchronize migrations with actual schema (#9965)

store/sqlstore/supplier.go

@@ -677,6 +677,52 @@ func (ss *SqlSupplier) AlterColumnTypeIfExists(tableName string, columnName stri
 	return true
 }
 
+func (ss *SqlSupplier) AlterColumnDefaultIfExists(tableName string, columnName string, mySqlColDefault *string, postgresColDefault *string) bool {
+	if !ss.DoesColumnExist(tableName, columnName) {
+		return false
+	}
+
+	var defaultValue = ""
+	if ss.DriverName() == model.DATABASE_DRIVER_MYSQL {
+		// Some column types in MySQL cannot have defaults, so don't try to configure anything.
+		if mySqlColDefault == nil {
+			return true
+		}
+
+		defaultValue = *mySqlColDefault
+	} else if ss.DriverName() == model.DATABASE_DRIVER_POSTGRES {
+		// Postgres doesn't have the same limitation, but preserve the interface.
+		if postgresColDefault == nil {
+			return true
+		}
+
+		tableName = strings.ToLower(tableName)
+		columnName = strings.ToLower(columnName)
+		defaultValue = *postgresColDefault
+	} else {
+		mlog.Critical("Failed to alter column default because of missing driver")
+		time.Sleep(time.Second)
+		os.Exit(EXIT_GENERIC_FAILURE)
+		return false
+	}
+
+	var err error
+	if defaultValue == "" {
+		_, err = ss.GetMaster().ExecNoTimeout("ALTER TABLE " + tableName + " ALTER COLUMN " + columnName + " DROP DEFAULT")
+	} else {
+		_, err = ss.GetMaster().ExecNoTimeout("ALTER TABLE " + tableName + " ALTER COLUMN " + columnName + " SET DEFAULT " + defaultValue)
+	}
+
+	if err != nil {
+		mlog.Critical(fmt.Sprintf("Failed to alter column %s.%s default %s: %v", tableName, columnName, defaultValue, err))
+		time.Sleep(time.Second)
+		os.Exit(EXIT_GENERIC_FAILURE)
+		return false
+	}
+
+	return true
+}
+
 func (ss *SqlSupplier) CreateUniqueIndexIfNotExists(indexName string, tableName string, columnName string) bool {
 	return ss.createIndexIfNotExists(indexName, tableName, []string{columnName}, INDEX_TYPE_DEFAULT, true)
 }