xugu_driver_go/参数映射失败.txt

func (rs *Rows) nextLocked() (doClose, ok bool) {
	if rs.closed {
		return false, false
	}

	// Lock the driver connection before calling the driver interface
	// rowsi to prevent a Tx from rolling back the connection at the same time.
	rs.dc.Lock()
	defer rs.dc.Unlock()

	if rs.lastcols == nil {
		rs.lastcols = make([]driver.Value, len(rs.rowsi.Columns()))
	}

	rs.lasterr = rs.rowsi.Next(rs.lastcols)


-------

func (rs *Rows) Next() bool {
	// If the user's calling Next, they're done with their previous row's Scan
	// results (any RawBytes memory), so we can release the read lock that would
	// be preventing awaitDone from calling close.
	rs.closemuRUnlockIfHeldByScan()

	if rs.contextDone.Load() != nil {
		return false
	}

	var doClose, ok bool
	withLock(rs.closemu.RLocker(), func() {
		doClose, ok = rs.nextLocked()
	})


	----------
	func (rs *Rows) Scan(dest ...any) error {
		fmt.Printf("驱动内部的 sCan %#v \n", dest)
		if rs.closemuScanHold {
			// This should only be possible if the user calls Scan twice in a row
			// without calling Next.
			return fmt.Errorf("sql: Scan called without calling Next (closemuScanHold)")
		}
		rs.closemu.RLock()
	
		if rs.lasterr != nil && rs.lasterr != io.EOF {
			rs.closemu.RUnlock()
			return rs.lasterr
		}
		if rs.closed {
			err := rs.lasterrOrErrLocked(errRowsClosed)
			rs.closemu.RUnlock()
			return err
		}
	
		if scanArgsContainRawBytes(dest) {
			rs.closemuScanHold = true
		} else {
			rs.closemu.RUnlock()
		}
	
		if rs.lastcols == nil {
			rs.closemuRUnlockIfHeldByScan()
			return errors.New("sql: Scan called without calling Next")
		}
		if len(dest) != len(rs.lastcols) {
			fmt.Println(" len(rs.lastcols)", len(rs.lastcols))
			fmt.Println(" len(dest) ", len(dest), dest)
			fmt.Println("列数据不匹配")
	
			rs.closemuRUnlockIfHeldByScan()
			return fmt.Errorf("sql: expected %d destination arguments in Scan, not %d", len(rs.lastcols), len(dest))
		}
		fmt.Println("列数据匹配")
		for i, sv := range rs.lastcols {
			err := convertAssignRows(dest[i], sv, rs)
			if err != nil {
				rs.closemuRUnlockIfHeldByScan()
				return fmt.Errorf(`sql: Scan error on column index %d, name %q: %w`, i, rs.rowsi.Columns()[i], err)
			}
		}
		return nil
	}