Remove WriteWithPrompt workaround

Author: andyleejordan

src/PowerShellEditorServices/Services/PowerShell/Execution/SynchronousPowerShellTask.cs

@@ -62,7 +62,7 @@ public override IReadOnlyList<TResult> Run(CancellationToken cancellationToken)
 
                 if (PowerShellExecutionOptions.WriteInputToHost)
                 {
-                    _psesHost.WriteWithPrompt(_psCommand, cancellationToken);
+                    _psesHost.UI.WriteLine(_psCommand.GetInvocationText());
                 }
 
                 return _pwsh.Runspace.Debugger.InBreakpoint

src/PowerShellEditorServices/Services/PowerShell/Host/PsesInternalHost.cs

@@ -757,18 +757,22 @@ private void DoOneRepl(CancellationToken cancellationToken)
 
                 // If the user input was empty it's because:
                 //  - the user provided no input
-                //  - the readline task was canceled
-                //  - CtrlC was sent to readline (which does not propagate a cancellation)
+                //  - the ReadLine task was canceled
+                //  - CtrlC was sent to ReadLine (which does not propagate a cancellation)
                 //
-                // In any event there's nothing to run in PowerShell, so we just loop back to the prompt again.
-                // However, we must distinguish the last two scenarios, since PSRL will not print a new line in those cases.
+                // In any event there's nothing to run in PowerShell, so we just loop back to the
+                // prompt again. However, PSReadLine will not print a newline for CtrlC, so we print
+                // one, but we do not want to print one if the ReadLine task was canceled.
                 if (string.IsNullOrEmpty(userInput))
                 {
-                    if (cancellationToken.IsCancellationRequested || LastKeyWasCtrlC())
+                    if (LastKeyWasCtrlC())
                     {
                         UI.WriteLine();
                     }
-                    return;
+                    // Propogate cancellation if that's what happened, since ReadLine won't.
+                    // TODO: We may not need to do this at all.
+                    cancellationToken.ThrowIfCancellationRequested();
+                    return; // Task wasn't canceled but there was no input.
                 }
 
                 InvokeInput(userInput, cancellationToken);
@@ -782,10 +786,8 @@ private void DoOneRepl(CancellationToken cancellationToken)
             {
                 throw;
             }
-            catch (FlowControlException)
-            {
-                // Do nothing, a break or continue statement was used outside of a loop.
-            }
+            // Do nothing, a break or continue statement was used outside of a loop.
+            catch (FlowControlException) { }
             catch (Exception e)
             {
                 UI.WriteErrorLine($"An error occurred while running the REPL loop:{Environment.NewLine}{e}");
@@ -829,25 +831,16 @@ private string GetPrompt(CancellationToken cancellationToken)
             return prompt;
         }
 
-        /// <summary>
-        /// This is used to write the invocation text of a command with the user's prompt so that,
-        /// for example, F8 (evaluate selection) appears as if the user typed it. Used when
-        /// 'WriteInputToHost' is true.
-        /// </summary>
-        /// <param name="command">The PSCommand we'll print after the prompt.</param>
-        /// <param name="cancellationToken"></param>
-        public void WriteWithPrompt(PSCommand command, CancellationToken cancellationToken)
-        {
-            UI.Write(GetPrompt(cancellationToken));
-            UI.WriteLine(command.GetInvocationText());
-        }
-
         private string InvokeReadLine(CancellationToken cancellationToken)
         {
             cancellationToken.ThrowIfCancellationRequested();
             try
             {
+                // TODO: If we can pass the cancellation token to ReadKey directly in PSReadLine, we
+                // can remove this logic.
+                _logger.LogDebug("Saving ReadKey cancellation token and invoking ReadLine");
                 _readKeyCancellationToken = cancellationToken;
+                cancellationToken.ThrowIfCancellationRequested();
                 return _readLineProvider.ReadLine.ReadLine(cancellationToken);
             }
             finally