From a86b391591eee62cdd24b1cd7eda9398b1367697 Mon Sep 17 00:00:00 2001
From: Alberto Aldegheri <albyrock87@gmail.com>
Date: Thu, 21 Mar 2024 12:05:22 +0100
Subject: [PATCH] Capture navigation exceptions on shell controlled navigation

---
 .../Internals/NavigationService.cs                  |  8 ++++----
 .../InvalidNavigationException.cs                   |  7 +++++++
 Source/Nalu.Maui.Navigation/NaluShell.cs            | 13 ++++++++++++-
 3 files changed, 23 insertions(+), 5 deletions(-)
 create mode 100644 Source/Nalu.Maui.Navigation/InvalidNavigationException.cs

diff --git a/Source/Nalu.Maui.Navigation/Internals/NavigationService.cs b/Source/Nalu.Maui.Navigation/Internals/NavigationService.cs
index 346f47b..7d59fa6 100644
--- a/Source/Nalu.Maui.Navigation/Internals/NavigationService.cs
+++ b/Source/Nalu.Maui.Navigation/Internals/NavigationService.cs
@@ -55,7 +55,7 @@ public async Task<bool> GoToAsync(INavigationInfo navigation)
     {
         if (navigation.Count == 0)
         {
-            throw new InvalidOperationException("Navigation must contain at least one segment.");
+            throw new InvalidNavigationException("Navigation must contain at least one segment.");
         }
 
         var disposeBag = new HashSet<object>();
@@ -165,7 +165,7 @@ private async Task<bool> ExecuteRelativeNavigationAsync(
         var popCount = navigation.Count(segment => segment.SegmentName == NavigationPop.PopRoute);
         if (popCount >= stack.Count)
         {
-            throw new InvalidOperationException("Cannot pop more pages than the stack contains.");
+            throw new InvalidNavigationException("Cannot pop more pages than the stack contains.");
         }
 
         var navigationCount = navigation.Count;
@@ -465,7 +465,7 @@ private async Task<bool> ExecuteNavigationAsync(Func<Task<bool>> navigationFunc)
         var taken = await _semaphore.WaitAsync(0).ConfigureAwait(true);
         if (!taken)
         {
-            throw new InvalidOperationException("Cannot navigate while another navigation is in progress, try to use IDispatcher.DispatchDelayed.");
+            throw new InvalidNavigationException("Cannot navigate while another navigation is in progress, try to use IDispatcher.DispatchDelayed.");
         }
 
         try
@@ -517,7 +517,7 @@ private void DisposePage(object toDispose)
 
             default:
             {
-                throw new InvalidOperationException();
+                throw new InvalidNavigationException("Trying to dispose an unknown object.");
             }
         }
     }
diff --git a/Source/Nalu.Maui.Navigation/InvalidNavigationException.cs b/Source/Nalu.Maui.Navigation/InvalidNavigationException.cs
new file mode 100644
index 0000000..5d570f5
--- /dev/null
+++ b/Source/Nalu.Maui.Navigation/InvalidNavigationException.cs
@@ -0,0 +1,7 @@
+namespace Nalu;
+
+/// <summary>
+/// Represents an exception thrown when triggering a navigation that cannot be performed.
+/// </summary>
+public class InvalidNavigationException(string? message = null, Exception? innerException = null)
+    : Exception(message, innerException);
diff --git a/Source/Nalu.Maui.Navigation/NaluShell.cs b/Source/Nalu.Maui.Navigation/NaluShell.cs
index 1b5cae5..07054e3 100644
--- a/Source/Nalu.Maui.Navigation/NaluShell.cs
+++ b/Source/Nalu.Maui.Navigation/NaluShell.cs
@@ -1,5 +1,6 @@
 namespace Nalu;
 
+using System.Diagnostics;
 using System.Text.RegularExpressions;
 
 #pragma warning disable IDE0290
@@ -150,7 +151,17 @@ protected override async void OnNavigating(ShellNavigatingEventArgs args)
 
             await Task.Yield();
             await Task.Yield();
-            await _navigationService.GoToAsync(navigation).ConfigureAwait(true);
+            try
+            {
+                await _navigationService.GoToAsync(navigation).ConfigureAwait(true);
+            }
+            catch (InvalidNavigationException ex)
+            {
+                if (Debugger.IsAttached)
+                {
+                    Console.WriteLine(ex.Message);
+                }
+            }
         }
     }