Fyne error: Preferences load error

[alihongbo]

Describe the bug:

2022/04/21 20:15:04 Fyne error: Preferences load error:
2022/04/21 20:15:04 Cause: EOF
2022/04/21 20:15:04 At: ./vendor/fyne.io/fyne/v2/app/preferences.go:84

To Reproduce:

Steps to reproduce the behaviour:

Preferences is used in the project. At first, it is good. After running for a period of time, an error will be prompted. Even if the code of preferences is deleted from the project, the operation will still report an error.

Screenshots:

Example code:

xxx.Preferences().String("xxx")
xxx.Preferences().SetString("xxx","ccc")
xxx.Preferences().RemoveValue("xxx")

Device (please complete the following information):

• OS: MacOS
• Version: 11.6.2
• Go version: 1.18
• Fyne version: 2.1.4

[Jacalz]

Would you mind including the entire example code? Also, can you please try with the latest v2.1.x release (v2.1.4 at the time of writing)?

[alihongbo]

Trace the source code and find the ~/library/preferences/xxx/fyne directory. Delete the Fyne folder and no error will be reported. It is suspected that an exception occurred during the process of writing the configuration.

[alihongbo]

Would you mind including the entire example code? Also, can you please try with the latest v2.1.x release (v2.1.4 at the time of writing)?

yes v2.1.4

[Jacalz]

Trace the source code and find the ~/library/preferences/xxx/fyne directory. Delete the Fyne folder and no error will be reported. It is suspected that an exception occurred during the process of writing the configuration.

Sorry, I don’t understand what you mean with “tracing the source code”. Can you please add your example code (see information in the template) to the issue description?

[andydotxyz]

It does look like the code is generating some sort of invalid JSON somehow.
It would be really helpful to see the contents of the preference file that you have tracked down when this error occurs @HongBook

[alihongbo]

It does look like the code is generating some sort of invalid JSON somehow. It would be really helpful to see the contents of the preference file that you have tracked down when this error occurs @HongBook

the preference file is empty.

[alihongbo]

Trace the source code and find the ~/library/preferences/xxx/fyne directory. Delete the Fyne folder and no error will be reported. It is suspected that an exception occurred during the process of writing the configuration.

Sorry, I don’t understand what you mean with “tracing the source code”. Can you please add your example code (see information in the template) to the issue description?

I mean "debug".

[andydotxyz]

OK thanks. So somehow we are writing an empty file? This is super strange.
Does your app seem to lose data, or does the file write successfully when you exit the app?

[andydotxyz]

I think that @Bluebugs may have tracked this down and documented stack trace in #3015 - closing as duplicate of that which is going to be easier to track the fix.