From 56e4d88db0a1de0945215d2e930d848ad225baf3 Mon Sep 17 00:00:00 2001
From: Dan Siegel <me@dansiegel.net>
Date: Mon, 13 Nov 2023 18:22:56 -0600
Subject: [PATCH] chore: remove TaskCanceledException catch

---
 .../Commands/AsyncDelegateCommand.cs          | 24 ++++---------------
 .../Commands/AsyncDelegateCommand{T}.cs       | 19 +++++++--------
 2 files changed, 13 insertions(+), 30 deletions(-)

diff --git a/src/Prism.Core/Commands/AsyncDelegateCommand.cs b/src/Prism.Core/Commands/AsyncDelegateCommand.cs
index e748ad40d8..8c7eec460f 100644
--- a/src/Prism.Core/Commands/AsyncDelegateCommand.cs
+++ b/src/Prism.Core/Commands/AsyncDelegateCommand.cs
@@ -98,10 +98,6 @@ public async Task Execute(CancellationToken? cancellationToken = null)
             await _executeMethod(token)
                 .ConfigureAwait(false);
         }
-        catch (TaskCanceledException) when (token.IsCancellationRequested)
-        {
-            // Do nothing... the Task was cancelled
-        }
         catch (Exception ex)
         {
             if (!ExceptionHandler.CanHandle(ex))
@@ -145,23 +141,11 @@ public bool CanExecute()
     /// <param name="parameter">Command Parameter</param>
     protected override async void Execute(object? parameter)
     {
+        // We don't want to wrap this in a try/catch because we already handle
+        // or mean to rethrow the exception in the call with the CancellationToken.
         var cancellationToken = _getCancellationToken();
-        try
-        {
-            await Execute(cancellationToken)
-                .ConfigureAwait(false);
-        }
-        catch (TaskCanceledException) when (cancellationToken.IsCancellationRequested)
-        {
-            // Do nothing... the Task was cancelled
-        }
-        catch (Exception ex)
-        {
-            if (!ExceptionHandler.CanHandle(ex))
-                throw;
-
-            ExceptionHandler.Handle(ex, parameter);
-        }
+        await Execute(cancellationToken)
+            .ConfigureAwait(false);
     }
 
     /// <summary>
diff --git a/src/Prism.Core/Commands/AsyncDelegateCommand{T}.cs b/src/Prism.Core/Commands/AsyncDelegateCommand{T}.cs
index 4ed68524da..a449f5c67b 100644
--- a/src/Prism.Core/Commands/AsyncDelegateCommand{T}.cs
+++ b/src/Prism.Core/Commands/AsyncDelegateCommand{T}.cs
@@ -101,10 +101,6 @@ public async Task Execute(T parameter, CancellationToken? cancellationToken = nu
             await _executeMethod(parameter, token)
                 .ConfigureAwait(false);
         }
-        catch (TaskCanceledException) when (token.IsCancellationRequested)
-        {
-            // Do nothing... the Task was cancelled
-        }
         catch (Exception ex)
         {
             if (!ExceptionHandler.CanHandle(ex))
@@ -149,14 +145,10 @@ public bool CanExecute(T parameter)
     protected override async void Execute(object? parameter)
     {
         var cancellationToken = _getCancellationToken();
+        T parameterAsT;
         try
         {
-            await Execute((T)parameter!, cancellationToken)
-                .ConfigureAwait(false);
-        }
-        catch (TaskCanceledException) when (cancellationToken.IsCancellationRequested)
-        {
-            // Do nothing... the Task was cancelled
+            parameterAsT = (T)parameter!;
         }
         catch (Exception ex)
         {
@@ -164,7 +156,14 @@ await Execute((T)parameter!, cancellationToken)
                 throw;
 
             ExceptionHandler.Handle(ex, parameter);
+            return;
         }
+
+        // If we had an exception casting the parameter to T ,
+        // we would have already returned. We want to surface any
+        // exceptions thrown by the Execute method.
+        await Execute(parameterAsT, cancellationToken)
+            .ConfigureAwait(false);
     }
 
     /// <summary>