fix: improve errors when running against Konnect with workspace config

CHANGELOG.md

@@ -66,6 +66,8 @@
   with Konnect cloud. A clear error message is provided when this
   command is invoked.
   [#718](https://github.com/Kong/deck/pull/#718)
+- Improve error message when workspace is used in Konnect mode.
+  [#696](https://github.com/Kong/deck/pull/696)
 
 ## [v1.14.0]
 

cmd/common.go

@@ -103,6 +103,15 @@ func syncMain(ctx context.Context, filenames []string, dry bool, parallelism,
 	var kongClient *kong.Client
 	mode := getMode(targetContent)
 	if mode == modeKonnect {
+		if targetContent.Workspace != "" {
+			return fmt.Errorf("_workspace set in config file.\n"+
+				"Workspaces are not supported in Konnect. "+
+				"Please remove '_workspace: %s' from your "+
+				"configuration and try again", targetContent.Workspace)
+		}
+		if workspace != "" {
+			return fmt.Errorf("--workspace flag is not supported when running against Konnect")
+		}
 		if targetContent.Konnect != nil {
 			if konnectRuntimeGroup != "" &&
 				targetContent.Konnect.RuntimeGroupName != konnectRuntimeGroup {