Improve error message when removing a workshop twice

internal/daemon/api_workshops.go

@@ -662,7 +662,9 @@ func v1PostProjectWorkshop(c *Command, r *http.Request, _ *userState) Response {
 		return changeConflictErrorResponse(changeConflictErr)
 	case errors.Is(err, conflict.ErrorNoWaitingChange):
 		return noWaitingChangeResponse(err)
-	case err != nil:
+	case errors.Is(err, workshop.ErrWorkshopNotLaunched):
+		return statusNotFound("%w", err)
+	default:
 		return statusBadRequest("%w", err)
 	}
 

internal/daemon/api_workshops_test.go

@@ -4330,8 +4330,8 @@ func (s *apiSuite) TestValidateIncorrectActionModeInputs(c *check.C) {
 		}, {
 			cmd: "remove",
 			result: map[string]string{
-				"":              `cannot remove "basic": workshop not launched`,
-				"transactional": `cannot remove "basic": workshop not launched`,
+				"":              `cannot remove "basic": workshop already removed`,
+				"transactional": `cannot remove "basic": workshop already removed`,
 				"wait-on-error": `cannot remove: mode "wait-on-error" is not valid with the "remove" command`,
 				"continue":      `cannot remove: mode "continue" is not valid with the "remove" command`,
 				"abort":         `cannot remove: mode "abort" is not valid with the "remove" command`,
@@ -4353,6 +4353,9 @@ func (s *apiSuite) TestValidateIncorrectActionModeInputs(c *check.C) {
 				Status:  http.StatusBadRequest,
 				Message: experr,
 			}
+			if strings.HasSuffix(experr, "workshop not launched") || strings.HasSuffix(experr, "workshop already removed") {
+				exp.Status = http.StatusNotFound
+			}
 
 			// Execute
 			rsp := v1PostProjectWorkshop(apiCmd("/v1/projects/{id}/workshops"), req, nil).(*resp)
@@ -5418,8 +5421,8 @@ func (s *apiSuite) TestRemoveWorkshopNotFound(c *check.C) {
 	expected := []*expectedResp{
 		{
 			Type:    ResponseTypeError,
-			Status:  http.StatusBadRequest,
-			Message: `cannot remove "workshopconns": workshop not launched`,
+			Status:  http.StatusNotFound,
+			Message: `cannot remove "workshopconns": workshop already removed`,
 		},
 	}
 	s.runActionTest(c, requests, expected)

internal/overlord/workshopstate/manifest.go

@@ -142,6 +142,9 @@ func (w *WorkshopManager) RemoveManifests(ctx context.Context, projectId string,
 	running = make(map[string]bool, len(names))
 	for _, name := range names {
 		wp, err := w.backend.Workshop(ctx, name)
+		if errors.Is(err, workshop.ErrWorkshopNotLaunched) {
+			err = errAlreadyRemoved{}
+		}
 		if err != nil {
 			return nil, nil, nil, fmt.Errorf("cannot remove %q: %w", name, err)
 		}
@@ -171,6 +174,16 @@ func (w *WorkshopManager) RemoveManifests(ctx context.Context, projectId string,
 	return stashed, current, running, nil
 }
 
+type errAlreadyRemoved struct{}
+
+func (errAlreadyRemoved) Error() string {
+	return "workshop already removed"
+}
+
+func (errAlreadyRemoved) Unwrap() error {
+	return workshop.ErrWorkshopNotLaunched
+}
+
 func (w *WorkshopManager) maybeDiscardWaitingRefresh(projectId string, file *workshop.File) (*Manifest, error) {
 	err := conflict.CheckChangeConflict(w.state, projectId, file.Name, []string{"exec"})
 	if err == nil {