SaveTo method, the whitespaces are missing

[billychou]

Describe the bug
Hi ,
As shown below, the reg_gsid value contains a blank space.
my.ini

[access_log]
reg_gsid = ` (\d{39,41}) `

cfg, err := ini.Load("my.ini")
cfg.SaveTo("local.ini")

As shown above， the blank space is gone when i use saveTo method.
Please, How to reverse the blank space when i use the method. Thanks a lot.

To Reproduce

cfg, err := ini.Load(file)
if err != nil {
	log.Fatal(err)
}
if strings.HasPrefix(regGsid, " ") {
	println("regGsid prefix blank")
}
cfg.SaveTo("local.ini")
newcfg, err := ini.Load("local.ini")
if err != nil {
	log.Fatal(err)
}
newRegGsid := newcfg.Section("access_log").Key("reg_gsid").String()
if strings.HasPrefix(newRegGsid, " ") {
	fmt.Println("newRegGsid prefix blank")
}

Expected behavior
A clear and concise description of what you expected to happen.

Screenshots

Additional context
Add any other context about the problem here, or any suggestion to fix the problem.

[unknwon]

The problem is we don't check leading and trailing whitespaces in

ini/file.go

Line 383 in 09e0d86

if strings.Contains(kname, "\"") || strings.ContainsAny(kname, f.options.KeyValueDelimiters) {

and

ini/file.go

Line 426 in 09e0d86

case strings.Contains(kname, "\"") || strings.ContainsAny(kname, f.options.KeyValueDelimiters):

[prepodavan]

test file_test.go#TestFile_WriteTo compares full.ini and golden file. They have key lots_of_lines (last one). Parser produce value with trailing space without quoting "1 2 3 4 " because actually last line in full.ini has trailing space - "4 " (space between 4 and ).
As I understand there's only one direct way how file.go#writeToBuffer could recognize should or should not any value be surrounded by any quote char - len(strings.TrimSpace(value)) != len(value). But such way will quote lots_of_lines value and produce "1 2 3 4 " not "1 2 3 4" so test file_test.go#TestFile_WriteTo will fail compairing to golden.
To fix this issue in such way either or last line of full.ini should be changed to 4\ (from 4 \) or golden should quote value of lots_of_lines so it will be "1 2 3 4 " (with trailing space inside quotes).
Otherwise you have to remember somehow in code values which should be surrounded. This way will require a lot of changes as far as parser reading functions returns just string value and error without any context (except context of parser itself). So i guess way with changing old behaviour anyhow is more preferable.
I would like to fix this issue anyway and I came to ask which way is more preferable

[unknwon]

Thanks @prepodavan!

Golden file is just a way to "cache" expected results, if the comparison failed in a desired way, we just need to update the golden file (with -update flag) :)