[iOS, Mac] Exception should be thrown when shell item is null

[HarishwaranVijayakumar]

Note

Are you waiting for the changes in this PR to be merged?
It would be very helpful if you could test the resulting artifacts from this PR and let us know in a comment if this change resolves your issue. Thank you!

Issue Details

• When the Shell item is null, an exception is thrown on Windows and Android, but not on iOS and Mac.

Root Cause of the issue

• Since the Shell does not contain any items, the Shell item is null. Instead of throwing an exception in iOS, the source code simply returns.

Description of Change

• To ensure consistent behavior across all platforms, this pull request improves error handling in the ShellRenderer class for iOS and Mac. The SetupCurrentShellItem method has been updated to throw an InvalidOperationException when no current item is present."

For Windows, Issue will be fixed by this PR 28879

Tested the behaviour in the following platforms

• Windows
• Android
• iOS
• Mac

Output

Before Fix	After Fix

[dotnet-policy-service]

Hey there @@HarishwaranVijayakumar! Thank you so much for your PR! Someone from the team will get assigned to your PR shortly and we'll get it reviewed.

[jsuarezruiz]

This is aligning the behavior with other platforms?

[HarishwaranVijayakumar]

@jsuarezruiz Yes on Android, InvalidOperationException is thrown. On windows, this pr #28879 will ensure the same behavior

[rmarinho]

What is the case where ShellItem is null?

[HarishwaranVijayakumar]

@rmarinho If the ShellItem is null, an InvalidOperationException will be thrown

[mattleibow]

The fact that this PR is for ios and mac and this other one is for windows: #28879

this means only android throws. Maybe android is wrong.

[mattleibow]

This is what android does, for future me

maui/src/Controls/src/Core/Compatibility/Handlers/Shell/Android/ShellItemRenderer.cs

Lines 79 to 83 in 6262d96

	if (ShellItem is null)
	throw new InvalidOperationException("Active Shell Item not set. Have you added any Shell Items to your Shell?");
	if (ShellItem.CurrentItem is null)
	throw new InvalidOperationException($"Content not found for active {ShellItem}. Title: {ShellItem.Title}. Route: {ShellItem.Route}.");

[mattleibow]

This needs a test to be shared. Probably worth merging with #28879

[HarishwaranVijayakumar]

Closing this PR, since the changes are merged into this PR #28879