FIX: NavItem and Composer prop overriding was broken (#17092)

app/assets/javascripts/discourse/app/controllers/composer.js

@@ -136,7 +136,7 @@ export default Controller.extend({
   },
 
   set disableSubmit(value) {
-    this.set("_disableSubmit", value);
+    return this.set("_disableSubmit", value);
   },
 
   @discourseComputed("showPreview")

app/assets/javascripts/discourse/app/models/nav-item.js

@@ -27,7 +27,7 @@ const NavItem = EmberObject.extend({
     },
 
     set(value) {
-      this.set("_title", value);
+      return this.set("_title", value);
     },
   },
 
@@ -56,7 +56,7 @@ const NavItem = EmberObject.extend({
     },
 
     set(value) {
-      this.set("_displayName", value);
+      return this.set("_displayName", value);
     },
   },
 

app/assets/javascripts/discourse/tests/unit/models/nav-item-test.js

@@ -57,4 +57,29 @@ module("Unit | Model | nav-item", function (hooks) {
       "it updates when a new message arrives"
     );
   });
+
+  test("displayName", function (assert) {
+    const navItem = createStore().createRecord("nav-item", {
+      name: "something",
+    });
+
+    assert.strictEqual(
+      navItem.displayName,
+      "[en.filters.something.title count=0]"
+    );
+
+    navItem.set("displayName", "Extra Item");
+    assert.strictEqual(navItem.displayName, "Extra Item");
+  });
+
+  test("title", function (assert) {
+    const navItem = createStore().createRecord("nav-item", {
+      name: "something",
+    });
+
+    assert.strictEqual(navItem.title, "[en.filters.something.help]");
+
+    navItem.set("title", "Extra Item");
+    assert.strictEqual(navItem.title, "Extra Item");
+  });
 });