openSaveFileDialog if click esc will panic in windows

[woailv]

Description

`func (m *windowSaveFileDialog) show() (chan string, error) {
files := make(chan string)
defaultFolder, err := getDefaultFolder(m.dialog.directory)
if err != nil {
close(files)
return files, err
}

config := cfd.DialogConfig{
	Title:       m.dialog.title,
	Role:        "SaveFile",
	FileFilters: convertFilters(m.dialog.filters),
	FileName:    m.dialog.filename,
	Folder:      defaultFolder,
}

// Original PR for v2 by @almas1992: https://github.com/wailsapp/wails/pull/3205
if len(m.dialog.filters) > 0 {
	config.DefaultExtension = strings.TrimPrefix(strings.Split(m.dialog.filters[0].Pattern, ";")[0], "*")
}

result, err := showCfdDialog(
	func() (cfd.Dialog, error) {
		return cfd.NewSaveFileDialog(config)
	}, false)
go func() {
	defer handlePanic()
	v, ok := result.(string)// This is right code
	if ok {
		files <- v
		close(files)
	}
}()
return files, err

}`

To Reproduce

1. application.SaveFileDialog().SetFilename(fmt.Sprintf("%s.rem", f.Ternary(req.Name != "", req.Name, "temp"))).AddFilter("Files", "*.rem").PromptForSingleSelection()

Expected behaviour

1. application.SaveFileDialog().SetFilename(fmt.Sprintf("%s.rem", f.Ternary(req.Name != "", req.Name, "temp"))).AddFilter("Files", "*.rem").PromptForSingleSelection()

Screenshots

No response

Attempted Fixes

No response

System Details

windows10_x64

Additional context

No response

[github-actions]

👋 Thanks for reporting this issue! To help us investigate, could you please:

1. Add the output of wails doctor if not already included
2. Provide clear steps to reproduce the issue
3. If possible, create a minimal reproduction of the issue

This will help us resolve your issue much faster. Thank you!

[dosubot]

Hi @woailv! I'm Dosu and I’m helping the wails team.

This panic happens because when you press ESC to cancel the save file dialog, the result may not be a string (it could be nil or another type), but the code always type asserts it to string without checking for cancellation or errors first. This can cause a panic if the dialog was cancelled or closed unexpectedly.

Recent Wails updates have fixed this by improving error handling for file dialogs on Windows, especially for cancellation scenarios like pressing ESC. These fixes are included in pull requests such as #4019, #4253, and #4284, which ensure that cancellation is properly reported and prevent panics by handling non-string results and errors more robustly.

If you can't upgrade to a version with these fixes, you should check for cancellation errors before type asserting the result to string, and handle nil or empty results defensively in your code. If you want more specific advice, sharing the exact panic message or stack trace would help narrow it down.

To reply, just mention @dosu.

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[leaanthony]

PR Merged 👍