Fix: CLI commands return incorrect exit codes when AppHost fails (#12923)

* Initial plan

* Fix aspire deploy exit code bug - remove Environment.Exit from backchannel disconnect handler

Co-authored-by: davidfowl <[email protected]>

* Remove placeholder issue URL from comment

Co-authored-by: davidfowl <[email protected]>

* Use apphost exit code directly and remove unnecessary await

Co-authored-by: davidfowl <[email protected]>

* Tweaks to allow correct error code reporting on a rude exit from app host.

---------

Co-authored-by: copilot-swe-agent[bot] <[email protected]>
Co-authored-by: davidfowl <[email protected]>
Co-authored-by: Mitch Denny <[email protected]>

Author: 3 people

src/Aspire.Cli/Commands/PipelineCommandBase.cs

@@ -14,6 +14,7 @@
 using Aspire.Cli.Utils;
 using Aspire.Hosting;
 using Spectre.Console;
+using StreamJsonRpc;
 
 namespace Aspire.Cli.Commands;
 
@@ -101,6 +102,9 @@ protected PipelineCommandBase(string name, string description, IDotNetCliRunner
 
     protected override async Task<int> ExecuteAsync(ParseResult parseResult, CancellationToken cancellationToken)
     {
+        var debugMode = parseResult.GetValue<bool?>("--debug") ?? false;
+        Task<int>? pendingRun = null;
+
         // Send terminal infinite progress bar start sequence
         StartTerminalProgressBar();
 
@@ -199,7 +203,7 @@ protected override async Task<int> ExecuteAsync(ParseResult parseResult, Cancell
 
             var unmatchedTokens = parseResult.UnmatchedTokens.ToArray();
 
-            var pendingRun = _runner.RunAsync(
+            pendingRun = _runner.RunAsync(
                 effectiveAppHostFile,
                 false,
                 true,
@@ -222,8 +226,6 @@ protected override async Task<int> ExecuteAsync(ParseResult parseResult, Cancell
             });
 
             var publishingActivities = backchannel.GetPublishingActivitiesAsync(cancellationToken);
-
-            var debugMode = parseResult.GetValue<bool?>("--debug") ?? false;
 
             // Check if debug or trace logging is enabled
             var logLevel = parseResult.GetValue(_logLevelOption);
@@ -242,17 +244,30 @@ protected override async Task<int> ExecuteAsync(ParseResult parseResult, Cancell
             await backchannel.RequestStopAsync(cancellationToken).ConfigureAwait(false);
             var exitCode = await pendingRun;
 
-            if (exitCode == 0 && noFailuresReported)
+            // If the apphost returned a non-zero exit code, use it directly.
+            // This ensures we properly propagate apphost failures (e.g., exceptions, crashes).
+            if (exitCode != 0)
             {
-                return ExitCodeConstants.Success;
+                if (debugMode)
+                {
+                    InteractionService.DisplayLines(operationOutputCollector.GetLines());
+                }
+                return exitCode;
             }
 
-            if (debugMode)
+            // If the apphost exited successfully (0) but reported failures via backchannel,
+            // return a failure exit code.
+            if (!noFailuresReported)
             {
-                InteractionService.DisplayLines(operationOutputCollector.GetLines());
+                if (debugMode)
+                {
+                    InteractionService.DisplayLines(operationOutputCollector.GetLines());
+                }
+                return ExitCodeConstants.FailedToBuildArtifacts;
             }
 
-            return ExitCodeConstants.FailedToBuildArtifacts;
+            // Both apphost exit code and backchannel indicate success
+            return ExitCodeConstants.Success;
         }
         catch (OperationCanceledException)
         {
@@ -284,6 +299,14 @@ protected override async Task<int> ExecuteAsync(ParseResult parseResult, Cancell
             InteractionService.DisplayLines(operationOutputCollector.GetLines());
             return ExitCodeConstants.FailedToBuildArtifacts;
         }
+        catch (ConnectionLostException ex)
+        {
+            // Occurs if the apphost RPC channel is lost unexpectedly.
+            StopTerminalProgressBar();
+            InteractionService.DisplayError(string.Format(CultureInfo.CurrentCulture, InteractionServiceStrings.AppHostConnectionLost, ex.Message));
+            InteractionService.DisplayLines(operationOutputCollector.GetLines());
+            return pendingRun is { } && debugMode ? await pendingRun : ExitCodeConstants.FailedToBuildArtifacts;
+        }
         catch (Exception ex)
         {
             // Send terminal progress bar stop sequence on exception

src/Aspire.Cli/DotNet/DotNetCliRunner.cs

@@ -690,11 +690,10 @@ private async Task StartBackchannelAsync(Process? process, string socketPath, Ta
                 logger.LogTrace("Attempting to connect to AppHost backchannel at {SocketPath} (attempt {Attempt})", socketPath, connectionAttempts++);
                 await backchannel.ConnectAsync(socketPath, cancellationToken).ConfigureAwait(false);
                 backchannelCompletionSource.SetResult(backchannel);
-                backchannel.AddDisconnectHandler((_, _) =>
-                {
-                    // If the backchannel disconnects, we want to stop the CLI process
-                    Environment.Exit(ExitCodeConstants.Success);
-                });
+                // Note: We intentionally do not call Environment.Exit when the backchannel disconnects.
+                // The CLI should complete normally and return the appropriate exit code based on the
+                // deployment result. Calling Environment.Exit here would bypass the normal exit code
+                // logic and always return success (0), even when the deployment failed.
 
                 logger.LogDebug("Connected to AppHost backchannel at {SocketPath}", socketPath);
                 return;

src/Aspire.Cli/Resources/InteractionServiceStrings.Designer.cs

@@ -193,6 +193,9 @@
   <data name="ErrorConnectingToAppHost" xml:space="preserve">
     <value>An error occurred while connecting to the app host. The app host possibly crashed before it was available: {0}.</value>
   </data>
+  <data name="AppHostConnectionLost" xml:space="preserve">
+    <value>The connection to the app host was lost: {0}.</value>
+  </data>
   <data name="UnexpectedErrorOccurred" xml:space="preserve">
     <value>An unexpected error occurred: {0}</value>
     <comment>{0} is the exception message</comment>