FilePicker PickMultipleAsync nullable reference type

[aalsamoht]

Description

FilePicker.PickMultipleAsync() can return null.
The method declaration is Task<IEnumerable<FileResult?>> PickMultipleAsync(PickOptions? options = null);, but it should be Task<IEnumerable<FileResult>?> PickMultipleAsync(PickOptions? options = null);

The IEnumerable should be nullable, not the FileResult.

https://learn.microsoft.com/en-us/dotnet/api/microsoft.maui.storage.filepicker.pickmultipleasync?view=net-maui-10.0

See issue #27710

Steps to Reproduce

var fileResults = await filePicker.PickMultipleAsync(PickOptions.Default);

// Warning: Expression is always true according to nullable reference types' annotations
if (fileResults is not null)
{
    foreach (var fileResult in fileResults)
    {
        // Dereference of a possibly null reference
        Console.WriteLine(fileResult.FileName);
    }
}

Link to public reproduction project repository

No response

Version with bug

10.0.20

Is this a regression from previous behavior?

No, this is something new

Last version that worked well

No response

Affected platforms

iOS, Android, I was not able test on other platforms

Affected platform versions

No response

Did you find any workaround?

No response

Relevant log output

[HarishKumarSF4517]

This issue has been validated in Visual Studio Code 1.107.0 with MAUI versions (9.0.120, 10.0.0-preview.1, 10.0.0, 10.0.11 & 10.0.0-rc.2). It was not reproducible on Android and iOS platform. I have also attached the video for reference:

Android	IOS
FilePickerAndroid.mp4	FilePickerIOS.mp4

[aalsamoht]

@sheiksyedm @HarishKumarSF4517

The issue is about the compiler warnings for the nullable reference types.

It makes no sense to execute the code. This is not the problem described in the issue.

Reproduce by either:
- compiling the code in project with nullable reference types enabled
- reading the method signature and the method documentation

[HarishKumarSF4517]

This issue has been validated in Visual Studio Code 1.107.0 with MAUI versions (9.0.120, 10.0.0-preview.2, 10.0.0-preview.3, 10.0.11 & 10.0.0-rc.2). It was reproducible with Maui versions(10.0.0-preview.3, 10.0.11 & 10.0.0-rc.2) in Android and iOS platform. It was not reproducible below 10.0.0-preview3. Sample - FilePickerSample.zip