GetCellRichText strconv.Atoi error because of null value

[liuwangchao]

Description

大佬，我这有一个Excel文件：xml文件.zip，
其中F29和G29单元格，格式为t="s"，但是没有value:

-<row spans="1:7" r="29">
    <c r="A29" t="s" s="11"/>
    -<c r="B29" t="s" s="18">
        <v>103</v>
    </c>
    -<c r="C29" t="s" s="18">
        <v>104</v>
    </c>
    -<c r="D29" t="s" s="12">
        <v>105</v>
    </c>
    -<c r="E29" t="s" s="16">
        <v>106</v>
    </c>
    <c r="F29" t="s" s="16"/>
    <c r="G29" t="s" s="16"/>
</row>

这种异常情况在执行GetCellRichText方法时，

// GetCellRichText provides a function to get rich text of cell by given
// worksheet.
func (f *File) GetCellRichText(sheet, cell string) (runs []RichTextRun, err error) {
	ws, err := f.workSheetReader(sheet)
	if err != nil {
		return
	}
	c, _, _, err := ws.prepareCell(cell)
	if err != nil {
		return
	}
	if c.T == "inlineStr" && c.IS != nil {
		runs = getCellRichText(c.IS)
		return
	}
	if c.T == "" {
		return
	}
	siIdx, err := strconv.Atoi(c.V)
	if err != nil || c.T != "s" {
		return
	}
	sst, err := f.sharedStringsReader()
	if err != nil {
		return
	}
	if len(sst.SI) <= siIdx || siIdx < 0 {
		return
	}
	runs = getCellRichText(&sst.SI[siIdx])
	return
}

会由于strconv.Atoi(c.V)传入了空的c.V，导致报错strconv.Atoi: parsing "": invalid syntax
这边建议是在执行strconv.Atoi(c.V)前补充判断
把

if c.T == "" {
	return
}
siIdx, err := strconv.Atoi(c.V)
	if err != nil || c.T != "s" {
		return
}

改为

if c.T != "s" {
	return
}
if c.V == "" {
	return
}
siIdx, err := strconv.Atoi(c.V)
	if err != nil {
		return
}

修改完的完整方法如下：

// GetCellRichText provides a function to get rich text of cell by given
// worksheet.
func (f *File) GetCellRichText(sheet, cell string) (runs []RichTextRun, err error) {
	ws, err := f.workSheetReader(sheet)
	if err != nil {
		return
	}
	c, _, _, err := ws.prepareCell(cell)
	if err != nil {
		return
	}
	if c.T == "inlineStr" && c.IS != nil {
		runs = getCellRichText(c.IS)
		return
	}
	if c.T != "s" {
		return
	}
	if c.V == "" {
		return
	}
	siIdx, err := strconv.Atoi(c.V)
	if err != nil {
		return
	}
	sst, err := f.sharedStringsReader()
	if err != nil {
		return
	}
	if len(sst.SI) <= siIdx || siIdx < 0 {
		return
	}
	runs = getCellRichText(&sst.SI[siIdx])
	return
}