FIX: Reset the BBCode engine in every process

app/controllers/bb_code/admin/refresh_controller.rb

@@ -5,6 +5,8 @@ module Admin
     class RefreshController < ::Admin::AdminController
       requires_plugin PLUGIN_NAME
       def index
+        MessageBus.publish(::BbCode::ENGINE_RESET_CHANNEL, {})
+
         PrettyText.reset_context
         begin
           # Skip warmup in development mode - it makes boot take ~2s longer

assets/javascripts/discourse/api-initializers/engine-reset.js

@@ -0,0 +1,16 @@
+import { apiInitializer } from "discourse/lib/api";
+import { i18n } from "discourse-i18n";
+
+const RESET_CHANNEL = "/bbcode/engine-reset";
+
+export default apiInitializer((api) => {
+  api.container.lookup("service:message-bus").subscribe(RESET_CHANNEL, () => {
+    // The markdown-it feature is baked into the app bundle, so a reload is the
+    // only way to pick it up
+    api.addGlobalNotice(i18n("bbcode.reload_notice"), "bbcode-engine-reset", {
+      dismissable: true,
+      level: "info",
+      persistentDismiss: false,
+    });
+  });
+});

config/locales/client.en.yml

@@ -2,7 +2,8 @@ en:
   js:
     bbcode:
       title: "BBCode"
-      resetDesc: "The following resets the Markdown-It engine in the backend. This allows the engine to load in the latest code from the custom parser."
+      resetDesc: "Loads the latest custom parser code into every server process, without a restart. Open browser sessions are shown a banner asking them to refresh, since previews run the parser in the browser."
+      reload_notice: "The BBCode parser was updated. Refresh the page to use the latest version."
       reset: "Reset BBCode Engine"
       success: "Successfully reset."
       error: "Failed to reset. Please check logs."

plugin.rb

@@ -22,6 +22,8 @@
 
 module ::BbCode
   PLUGIN_NAME = "BbCode"
+
+  ENGINE_RESET_CHANNEL = "/bbcode/engine-reset"
 end
 
 require_relative "lib/bb_code/engine"
@@ -31,6 +33,10 @@ module ::BbCode
   # should clear out the context so the initial setup logic for bbcode parser runs
   PrettyText.reset_context()
 
+  unless Rails.env.test?
+    MessageBus.subscribe(::BbCode::ENGINE_RESET_CHANNEL) { PrettyText.reset_context }
+  end
+
   # overrides the default normalize_whitespaces function in discourse/lib/text_cleaner.rb
   # adds discourse_normalize_whitespace setting (defaults to false)
   # when true, normalize_whitespace runs as normal