InsertRow after stream writing is useless

[eaglexiang]

Description

I tried to insert one empty row after stream writing a excel file, no new line was inserted.

By the way, result of insert operation after normal writing is correct.

Steps to reproduce the issue:

1. create a new excel file by excelize
2. create a stream writer and write some cells.
3. flush stream writer and call method File.InsertRow
4. save excel as file.

// empty line found at A1
package main

import "github.com/360EntSecGroup-Skylar/excelize/v2"

func main() {
	ef := excelize.NewFile()

	err := ef.SetCellDefault("Sheet1", "A1", "test")
	if err != nil {
		panic(err)
	}

	err = ef.InsertRow("Sheet1", 1)
	if err != nil {
		panic(err)
	}

	err = ef.SaveAs("test.xlsx")
	if err != nil {
		panic(err)
	}
}

// no empty line
package main

import "github.com/360EntSecGroup-Skylar/excelize/v2"

func main() {
	ef := excelize.NewFile()

	sw, err := ef.NewStreamWriter("Sheet1")
	if err != nil {
		panic(err)
	}

	err = sw.SetRow("A1", []interface{}{"test"})
	if err != nil {
		panic(err)
	}
	err = sw.Flush()
	if err != nil {
		panic(err)
	}

	err = ef.InsertRow("Sheet1", 1)
	if err != nil {
		panic(err)
	}

	err = ef.SaveAs("test.xlsx")
	if err != nil {
		panic(err)
	}
}

Describe the results you received:

one excel file filled with only my test data.

Describe the results you expected:

one excel file filled with my test data and one empty line.

Output of go version:

go version go1.16.3 linux/amd64

Excelize version or commit ID:

v2.4.0

Environment details (OS, Microsoft Excel™ version, physical, etc.):

LSB Version: n/a
Distributor ID: ManjaroLinux
Description: Manjaro Linux
Release: 21.0.2
Codename: Ornara

[xuri]

We can't use common API and stream API mixed, this issue is similar to issues #725 and #777.

[eaglexiang]

Okay, I can follow your api rules. However, I need a way to create a huge excel with headers, which is built with merged cells like:

| header0 |         header1      |
|         | --------- | -------- |
|         |  header2  |  header  |

What's the typical way?

[xuri]

The Excelize doesn't support merge cell in streaming mode currently, I'll add this feature recently.

[xuri]

Hi @eaglexiang, I have just support merge cell in streaming mode, please try to use the master branch code, and this feature will be released in the next version.