[BUGFIX release] Improve assert in default store

packages/@ember/-internals/routing/lib/system/route.ts

@@ -25,7 +25,6 @@ import Controller from '@ember/controller';
 import { assert, info, isTesting } from '@ember/debug';
 import { dependentKeyCompat } from '@ember/object/compat';
 import { once } from '@ember/runloop';
-import { classify } from '@ember/string';
 import { DEBUG } from '@glimmer/env';
 import { Template, TemplateFactory } from '@glimmer/interfaces';
 import {
@@ -1736,16 +1735,18 @@ class Route extends EmberObject.extend(ActionHandler, Evented) implements IRoute
   protected get store() {
     let owner = getOwner(this);
     let routeName = this.routeName;
-    let namespace = get(this, '_router.namespace');
 
     return {
       find(name: string, value: unknown) {
         let modelClass: any = owner.factoryFor(`model:${name}`);
 
         assert(
-          `You used the dynamic segment ${name}_id in your route ${routeName}, but ${namespace}.${classify(
-            name
-          )} did not exist and you did not override your route's \`model\` hook.`,
+          `You used the dynamic segment \`${name}_id\` in your route ` +
+            `\`${routeName}\` for which Ember requires you provide a ` +
+            `data-loading implementation. Commonly, that is done by ` +
+            `adding a model hook implementation on the route ` +
+            `(\`model({${name}_id}) {\`) or by injecting an implemention of ` +
+            `a data store: \`@service store;\`.`,
           Boolean(modelClass)
         );
 
@@ -1755,7 +1756,22 @@ class Route extends EmberObject.extend(ActionHandler, Evented) implements IRoute
 
         modelClass = modelClass.class;
 
-        assert(`${classify(name)} has no method \`find\`.`, typeof modelClass.find === 'function');
+        assert(
+          `You used the dynamic segment \`${name}_id\` in your route ` +
+            `\`${routeName}\` for which Ember requires you provide a ` +
+            `data-loading implementation. Commonly, that is done by ` +
+            `adding a model hook implementation on the route ` +
+            `(\`model({${name}_id}) {\`) or by injecting an implemention of ` +
+            `a data store: \`@service store;\`.\n\n` +
+            `Rarely, applications may attempt to use a legacy behavior where ` +
+            `the model class (in this case \`${name}\`) is resolved and the ` +
+            `\`find\` method on that class is invoked to load data. In this ` +
+            `application, a model of \`${name}\` was found but it did not ` +
+            `provide a \`find\` method. You should not add a \`find\` ` +
+            `method to your model. Instead, please implement an appropriate ` +
+            `\`model\` hook on the \`${routeName}\` route.`,
+          typeof modelClass.find === 'function'
+        );
 
         return modelClass.find(value);
       },

packages/@ember/-internals/routing/tests/system/route_test.js

@@ -70,14 +70,31 @@ moduleFor(
       let owner = buildOwner();
       let Post = EmberObject.extend();
 
-      owner.register('route:index', EmberRoute);
+      owner.register(
+        'route:index',
+        EmberRoute.extend({
+          routeName: 'index',
+        })
+      );
       owner.register('model:post', Post);
 
       route = owner.lookup('route:index');
 
       expectAssertion(function () {
         route.findModel('post', 1);
-      }, 'Post has no method `find`.');
+      }, `You used the dynamic segment \`post_id\` in your route ` +
+        `\`index\` for which Ember requires you provide a ` +
+        `data-loading implementation. Commonly, that is done by ` +
+        `adding a model hook implementation on the route ` +
+        `(\`model({post_id}) {\`) or by injecting an implemention of ` +
+        `a data store: \`@service store;\`.\n\n` +
+        `Rarely, applications may attempt to use a legacy behavior where ` +
+        `the model class (in this case \`post\`) is resolved and the ` +
+        `\`find\` method on that class is invoked to load data. In this ` +
+        `application, a model of \`post\` was found but it did not ` +
+        `provide a \`find\` method. You should not add a \`find\` ` +
+        `method to your model. Instead, please implement an appropriate ` +
+        `\`model\` hook on the \`index\` route.`);
 
       runDestroy(owner);
     }
@@ -86,13 +103,23 @@ moduleFor(
       runDestroy(route);
 
       let owner = buildOwner();
-      owner.register('route:index', EmberRoute);
+      owner.register(
+        'route:index',
+        EmberRoute.extend({
+          routeName: 'index',
+        })
+      );
 
       route = owner.lookup('route:index');
 
       expectAssertion(function () {
         route.model({ post_id: 1 });
-      }, /You used the dynamic segment post_id in your route undefined, but <.*:ember\d+>.Post did not exist and you did not override your route's `model` hook./);
+      }, `You used the dynamic segment \`post_id\` in your route ` +
+        `\`index\` for which Ember requires you provide a ` +
+        `data-loading implementation. Commonly, that is done by ` +
+        `adding a model hook implementation on the route ` +
+        `(\`model({post_id}) {\`) or by injecting an implemention of ` +
+        `a data store: \`@service store;\`.`);
 
       runDestroy(owner);
     }