DEV: prevents route nodes to leak on each test run (#14457)

Note this commit is also adding support for teardown in pre-initializers just like we have for initializers.

Co-authored-by: Jarek Radosz <jradosz@gmail.com>
Co-authored-by: David Taylor <david@taylorhq.com>

app/assets/javascripts/discourse/app/mapping-router.js

@@ -141,6 +141,11 @@ export function mapRoutes() {
     this.route("unknown", { path: "*path" });
   });
 }
+export function teardownRouter(container) {
+  const router = container.lookup("router:main");
+  const constructor = Object.getPrototypeOf(router).constructor;
+  constructor.dslCallbacks.splice(0, constructor.dslCallbacks.length);
+}
 
 export function registerRouter(registry) {
   registry.unregister("router:main");

app/assets/javascripts/discourse/app/pre-initializers/map-routes.js

@@ -1,6 +1,6 @@
 import Application from "@ember/application";
 import { isLegacyEmber } from "discourse-common/config/environment";
-import { registerRouter } from "discourse/mapping-router";
+import { registerRouter, teardownRouter } from "discourse/mapping-router";
 
 let originalBuildInstance;
 
@@ -23,4 +23,8 @@ export default {
       };
     }
   },
+
+  teardown(container) {
+    teardownRouter(container);
+  },
 };

app/assets/javascripts/discourse/tests/helpers/qunit-helpers.js

@@ -296,6 +296,11 @@ export function acceptance(name, optionsOrCallback) {
           initializer.teardown(this.container);
         }
       });
+      app._runInitializer("initializers", (initName, initializer) => {
+        if (initializer && initializer.teardown) {
+          initializer.teardown(this.container);
+        }
+      });
 
       if (LEGACY_ENV) {
         app.__registeredObjects__ = false;