Detect addons with customized treeForMethod names

The normal way for addons to implement custom treeFor hooks is to... just implement them.

But some addons mutate the `treeForMethods` table instead. In fact, some addons mutate *other addons* `treeForMethods` table. *sigh*

packages/compat/src/v1-addon.ts

@@ -70,6 +70,19 @@ const dynamicTreeHooks = Object.freeze([
   'treeForVendor',
 ]);
 
+const defaultMethods = {
+  app: 'treeForApp',
+  addon: 'treeForAddon',
+  'addon-styles': 'treeForAddonStyles',
+  'addon-templates': 'treeForAddonTemplates',
+  'addon-test-support': 'treeForAddonTestSupport',
+  public: 'treeForPublic',
+  styles: 'treeForStyles',
+  templates: 'treeForTemplates',
+  'test-support': 'treeForTestSupport',
+  vendor: 'treeForVendor',
+};
+
 const appPublicationDir = '_app_';
 const fastbootPublicationDir = '_fastboot_';
 
@@ -400,12 +413,22 @@ export default class V1Addon {
           // customized hook exists in actual code exported from their index.js
           this.mainModule[treeName] ||
           // addon instance doesn't match its own prototype
-          (realAddon.__proto__ && realAddon[treeName] !== realAddon.__proto__[treeName])
+          (realAddon.__proto__ && realAddon[treeName] !== realAddon.__proto__[treeName]) ||
+          this.customizesHookName(treeName)
         );
       })
     );
   }
 
+  private customizesHookName(treeName: string): boolean {
+    for (let [name, methodName] of Object.entries(defaultMethods)) {
+      if (methodName === treeName) {
+        return this.addonInstance.treeForMethods?.[name] !== methodName;
+      }
+    }
+    return false;
+  }
+
   @Memoize()
   private hasStockTree(treeName: AddonTreePath): boolean {
     if (this.suppressesTree(treeName)) {

packages/shared-internals/src/ember-cli-models.ts

@@ -109,6 +109,7 @@ interface BaseAddonInstance {
     public: string;
     vendor: string;
   };
+  treeForMethods: Record<string, string>;
 }
 
 export type AddonTreePath = keyof BaseAddonInstance['treePaths'];

tests/scenarios/stage1-test.ts

@@ -272,6 +272,26 @@ appScenarios
     externallyCustomized.pkg.name = 'externally-customized';
     troubleMaker.pkg.name = 'trouble-maker';
 
+    // an addon that customizes a tree by mutating treeForMethods
+    let patchesMethodName = baseAddon();
+    merge(patchesMethodName.files, {
+      injected: {
+        hello: { 'world.js': '// hello' },
+      },
+      'index.js': `
+        const { join } = require('path');
+        module.exports = {
+        name: 'patches-method-name',
+        included() {
+          this.treeForMethods['addon'] = 'notTheUsual';
+        },
+        notTheUsual() {
+          return join(this.root, 'injected');
+        }
+      }`,
+    });
+    patchesMethodName.pkg.name = 'patches-method-name';
+
     // an addon that customizes packageJSON['ember-addon'].main and then uses
     // stock trees. Setting the main actually changes the root for *all* stock
     // trees.
@@ -346,6 +366,7 @@ appScenarios
     project.addDependency(movedMain);
     project.addDependency(suppressed);
     project.addDependency(suppressedCustom);
+    project.addDependency(patchesMethodName);
 
     project.pkg['ember-addon'] = { paths: ['lib/disabled-in-repo-addon', 'lib/blacklisted-in-repo-addon'] };
     merge(project.files, loadFromFixtureData('blacklisted-addon-build-options'));
@@ -380,6 +401,10 @@ appScenarios
         assert.ok(fs.existsSync(join(workspaceDir, 'node_modules/externally-customized/public/hello/world.js')));
       });
 
+      test('custom tree hooks are detected when they have been customized via treeForMethod names', function (assert) {
+        assert.ok(fs.existsSync(join(workspaceDir, 'node_modules/patches-method-name/hello/world.js')));
+      });
+
       test('addon with customized ember-addon.main can still use stock trees', function (assert) {
         let fileContents = fs.readFileSync(join(workspaceDir, 'node_modules/moved-main/helpers/hello.js'));
         assert.ok(/hello-world/.test(fileContents.toString()));