Crash when trying to create a new tag in new tags UI

[MalteTasler]

Description

Files Preview (4.35) crashes when trying to create a new tag, as soon as I start typing the name for the new tag.

debug:

2023-02-16 10:29:16.0409|ERROR|AppUnhandledException|Object reference not set to an instance of an object.
System.NullReferenceException: Object reference not set to an instance of an object.
at Files.App.SettingsPages.Advanced.IsNameValid(String name)
at Files.App.SettingsPages.Advanced.NewTagTextBox_TextChanged(Object sender, TextChangedEventArgs e)
at ABI.Microsoft.UI.Xaml.Controls.TextChangedEventHandler.Do_Abi_Invoke(IntPtr thisPtr, IntPtr sender, IntPtr e)
--- End of stack trace from previous location ---
at WinRT.ExceptionHelpers.g__Throw|20_0(Int32 hr)
at ABI.Windows.ApplicationModel.Core.IUnhandledErrorMethods.Propagate(IObjectReference _obj)
at Microsoft.AppCenter.Utils.ApplicationLifecycleHelperWinUI.<.ctor>b__0_3(Object sender, UnhandledErrorDetectedEventArgs eventArgs)
--- End of stack trace from previous location ---
at Microsoft.AppCenter.Utils.ApplicationLifecycleHelperWinUI.<.ctor>b__0_3(Object sender, UnhandledErrorDetectedEventArgs eventArgs)
at ABI.System.EventHandler`1.Do_Abi_Invoke[TAbi](Void* thisPtr, IntPtr sender, TAbi args)

Steps To Reproduce

1. Go to the tags UI in settings
2. Click "new"
3. Start typing the name

Steps to fix

not been able to fix yet

Files Version

2.4.35.0

Windows Version

Windows 11 22H2 Build 22621.1194

Log file

2023-02-16 10:29:16.0409|ERROR|AppUnhandledException|Object reference not set to an instance of an object.
System.NullReferenceException: Object reference not set to an instance of an object.
at Files.App.SettingsPages.Advanced.IsNameValid(String name)
at Files.App.SettingsPages.Advanced.NewTagTextBox_TextChanged(Object sender, TextChangedEventArgs e)
at ABI.Microsoft.UI.Xaml.Controls.TextChangedEventHandler.Do_Abi_Invoke(IntPtr thisPtr, IntPtr sender, IntPtr e)
--- End of stack trace from previous location ---
at WinRT.ExceptionHelpers.g__Throw|20_0(Int32 hr)
at ABI.Windows.ApplicationModel.Core.IUnhandledErrorMethods.Propagate(IObjectReference _obj)
at Microsoft.AppCenter.Utils.ApplicationLifecycleHelperWinUI.<.ctor>b__0_3(Object sender, UnhandledErrorDetectedEventArgs eventArgs)
--- End of stack trace from previous location ---
at Microsoft.AppCenter.Utils.ApplicationLifecycleHelperWinUI.<.ctor>b__0_3(Object sender, UnhandledErrorDetectedEventArgs eventArgs)
filetags.db.txt

at ABI.System.EventHandler`1.Do_Abi_Invoke[TAbi](Void* thisPtr, IntPtr sender, TAbi args)

[MalteTasler]

added the filetagsdb if that might help

[ferrariofilippo]

Will be fixed with #11320. There was a missing null-check

[ferrariofilippo]

FYI @yaira2 I can open a separate PR to fix that (just need to add a ?) I think it would be better if you could hotfix that:
at Files.App.SettingsPage.Advanced.IsNameValid()

                return !(
			string.IsNullOrWhiteSpace(name) ||
			name.StartsWith('.') ||
			name.EndsWith('.') ||
			(name != editingTag?.Tag.Name && ViewModel.Tags.Any(tag => name == tag.Tag.Name))
		);

name != editingTag?TagName.Name

[ferrariofilippo]

@MalteTasler here's a workaround you can use in the meantime:

• Start editing a tag
• Cancel edit
• Now you should be able to create a tag

[yaira2]

@ferrariofilippo thanks for the fix!

[MalteTasler]

Thankyou!