Calling entry.SetPlaceHolder inside of OnChanged callback freezes app

[dweymouth]

Checklist

• I have searched the issue tracker for open issues that relate to the same problem, before opening a new one.
• This issue only relates to a single bug. I will open new issues for any other problems.

Describe the bug

Reported in Fyne discord.

Calling entry.SetPlaceHolder in the OnChanged callback when it's invoked from a select-all + backspace change (ie deleting all text) causes the app to freeze. It reportedly works in Fyne 2.3.5

How to reproduce

Run the example code. Type into the entry. Then Select all (Ctrl+A) and delete.

Screenshots

No response

Example code

package main

import (
    "fyne.io/fyne/v2/app"
    "fyne.io/fyne/v2/widget"
)

func main() {
    myApp := app.New()
    window := myApp.NewWindow("test")

    str := "hello"
    entry := widget.NewEntry()
    entry.SetText(str)
    entry.OnChanged = func(s string) {
        if entry.Text == "" {
            entry.SetPlaceHolder("bye")
        } else {
            str = s
        }
    }
    window.SetContent(entry)
    window.ShowAndRun()
}

Fyne version

2.4.3

Go compiler version

1.21.4

Operating system and version

Windows

Additional Information

No response

[Jacalz]

I think this should be a quite simple fix. We just have to look at all the places we are calling OnChanged and make sure we aren't holding any locks when doing so. A quick glance shows this:

fyne/widget/entry.go

Line 1097 in a09bbd7

e.OnChanged(e.Text)

fyne/widget/entry.go

Line 851 in a09bbd7

e.OnChanged(e.Text)

[Jacalz]

Fixed in upcoming v2.4.4 release