Function getColDefaultValue

pkg/table/column.go:623–666

(ctx expression.BuildContext, col *model.ColumnInfo, defaultVal any, args *getColOriginDefaultValue)

}

func getColDefaultValue(ctx expression.BuildContext, col *model.ColumnInfo, defaultVal any, args *getColOriginDefaultValue) (types.Datum, error) {
	if defaultVal == nil {
		return getColDefaultValueFromNil(ctx, col, args)
	}

	switch col.GetType() {
	case mysql.TypeTimestamp, mysql.TypeDate, mysql.TypeDatetime:
	default:
		value, err := CastColumnValue(ctx, types.NewDatum(defaultVal), col, false, false)
		if err != nil {
			return types.Datum{}, err
		}
		return value, nil
	}

	// Check and get timestamp/datetime default value.
	var needChangeTimeZone bool
	var explicitTz *time.Location
	// If the column's default value is not ZeroDatetimeStr nor CurrentTimestamp, should use the time zone of the default value itself.
	if col.GetType() == mysql.TypeTimestamp {
		if vv, ok := defaultVal.(string); ok && vv != types.ZeroDatetimeStr && !strings.EqualFold(vv, ast.CurrentTimestamp) {
			needChangeTimeZone = true
			// For col.Version = 0, the timezone information of default value is already lost, so use the system timezone as the default value timezone.
			explicitTz = timeutil.SystemLocation()
			if col.Version >= model.ColumnInfoVersion1 {
				explicitTz = time.UTC
			}
		}
	}
	value, err := expression.GetTimeValue(ctx, defaultVal, col.GetType(), col.GetDecimal(), explicitTz)
	if err != nil {
		return types.Datum{}, errGetDefaultFailed.GenWithStackByArgs(col.Name)
	}
	// If the column's default value is not ZeroDatetimeStr or CurrentTimestamp, convert the default value to the current session time zone.
	if needChangeTimeZone {
		t := value.GetMysqlTime()
		err = t.ConvertTimeZone(explicitTz, ctx.GetEvalCtx().Location())
		if err != nil {
			return value, err
		}
		value.SetMysqlTime(t)
	}
	return value, nil
}

func getColDefaultValueFromNil(ctx expression.BuildContext, col *model.ColumnInfo, args *getColOriginDefaultValue) (types.Datum, error) {
	if !mysql.HasNotNullFlag(col.GetFlag()) {