feat(engine): display and notify an error if rendering fails. Fix #774

espanso-engine/src/event/effect.rs

@@ -30,7 +30,7 @@ pub struct CursorHintCompensationEvent {
   pub cursor_hint_back_count: usize,
 }
 
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, Default)]
 pub struct TextInjectRequest {
   pub text: String,
   pub force_mode: Option<TextInjectMode>,

espanso-engine/src/event/mod.rs

@@ -49,7 +49,6 @@ impl Event {
 #[allow(clippy::upper_case_acronyms)]
 pub enum EventType {
   NOOP,
-  ProcessingError(String),
   ExitRequested(ExitMode),
   Exit(ExitMode),
   Heartbeat,
@@ -77,6 +76,7 @@ pub enum EventType {
   DiscardPrevious(internal::DiscardPreviousEvent),
   DiscardBetween(internal::DiscardBetweenEvent),
   Undo(internal::UndoEvent),
+  RenderingError,
 
   Disabled,
   Enabled,

espanso-engine/src/process/middleware/notification.rs

@@ -22,6 +22,7 @@ use crate::event::{Event, EventType};
 
 pub trait NotificationManager {
   fn notify_status_change(&self, enabled: bool);
+  fn notify_rendering_error(&self);
 }
 
 pub struct NotificationMiddleware<'a> {
@@ -45,6 +46,7 @@ impl<'a> Middleware for NotificationMiddleware<'a> {
     match &event.etype {
       EventType::Enabled => self.notification_manager.notify_status_change(true),
       EventType::Disabled => self.notification_manager.notify_status_change(false),
+      EventType::RenderingError => self.notification_manager.notify_rendering_error(),
       _ => {}
     }
 

espanso-engine/src/process/middleware/render.rs

@@ -22,7 +22,7 @@ use std::collections::HashMap;
 use log::error;
 
 use super::super::Middleware;
-use crate::event::{internal::RenderedEvent, Event, EventType};
+use crate::event::{effect::TextInjectRequest, internal::RenderedEvent, Event, EventType};
 use anyhow::Result;
 use thiserror::Error;
 
@@ -62,7 +62,7 @@ impl<'a> Middleware for RenderMiddleware<'a> {
     "render"
   }
 
-  fn next(&self, event: Event, _: &mut dyn FnMut(Event)) -> Event {
+  fn next(&self, event: Event, dispatch: &mut dyn FnMut(Event)) -> Event {
     if let EventType::RenderingRequested(m_event) = event.etype {
       match self.renderer.render(
         m_event.match_id,
@@ -91,7 +91,16 @@ impl<'a> Middleware for RenderMiddleware<'a> {
           }
           _ => {
             error!("error during rendering: {:?}", err);
-            return Event::caused_by(event.source_id, EventType::ProcessingError("An error has occurred during rendering, please examine the logs or contact support.".to_string()));
+
+            dispatch(Event::caused_by(
+                event.source_id,
+                EventType::TextInject(TextInjectRequest {
+                  text: "[Espanso]: An error occurred during rendering, please examine the logs for more information.".to_string(),
+                  ..Default::default()
+                }),
+              ));
+
+            return Event::caused_by(event.source_id, EventType::RenderingError);
           }
         },
       }