Use ContinueWith rather than finally for coroutine result types (microsoft#4669)

JohnMcPMS · web-flow · commit 414cd9aca99e · 2024-07-25T13:25:40.000-07:00
## Change
Use `ContinueWith` and `ExecuteSynchronously` to effectively make a
`finally` for the `Task` result object. Convert the existing `finally`
to only call `Complete` on exception.
diff --git a/src/PowerShell/CommonFiles/PowerShellCmdlet.cs b/src/PowerShell/CommonFiles/PowerShellCmdlet.cs
@@ -97,11 +97,14 @@ internal Task RunOnMTA(Func<Task> func)
                 this.Write(StreamType.Verbose, "Already running on MTA");
                 try
                 {
-                    return func();
+                    Task result = func();
+                    result.ContinueWith((task) => this.Complete(), TaskContinuationOptions.ExecuteSynchronously);
+                    return result;
                 }
-                finally
+                catch
                 {
                     this.Complete();
+                    throw;
                 }
             }
 
@@ -150,11 +153,14 @@ internal Task<TResult> RunOnMTA<TResult>(Func<Task<TResult>> func)
                 this.Write(StreamType.Verbose, "Already running on MTA");
                 try
                 {
-                    return func();
+                    Task<TResult> result = func();
+                    result.ContinueWith((task) => this.Complete(), TaskContinuationOptions.ExecuteSynchronously);
+                    return result;
                 }
-                finally
+                catch
                 {
                     this.Complete();
+                    throw;
                 }
             }
 

Original file line number	Diff line number	Diff line change
`@@ -97,11 +97,14 @@ internal Task RunOnMTA(Func<Task> func)`
`97`	`97`	`this.Write(StreamType.Verbose, "Already running on MTA");`
`98`	`98`	`try`
`99`	`99`	`{`
`100`		`- return func();`
	`100`	`+ Task result = func();`
	`101`	`+ result.ContinueWith((task) => this.Complete(), TaskContinuationOptions.ExecuteSynchronously);`
	`102`	`+ return result;`
`101`	`103`	`}`
`102`		`- finally`
	`104`	`+ catch`
`103`	`105`	`{`
`104`	`106`	`this.Complete();`
	`107`	`+ throw;`
`105`	`108`	`}`
`106`	`109`	`}`
`107`	`110`
`@@ -150,11 +153,14 @@ internal Task<TResult> RunOnMTA<TResult>(Func<Task<TResult>> func)`
`150`	`153`	`this.Write(StreamType.Verbose, "Already running on MTA");`
`151`	`154`	`try`
`152`	`155`	`{`
`153`		`- return func();`
	`156`	`+ Task<TResult> result = func();`
	`157`	`+ result.ContinueWith((task) => this.Complete(), TaskContinuationOptions.ExecuteSynchronously);`
	`158`	`+ return result;`
`154`	`159`	`}`
`155`		`- finally`
	`160`	`+ catch`
`156`	`161`	`{`
`157`	`162`	`this.Complete();`
	`163`	`+ throw;`
`158`	`164`	`}`
`159`	`165`	`}`
`160`	`166`