Remove _globalsMode and _prepareForGlobalsMode from Application

Co-authored-by: kategengler <444218+kategengler@users.noreply.github.com>

Author: Copilot

packages/@ember/application/index.ts

@@ -341,55 +341,6 @@ class Application extends Engine {
   */
   declare autoboot: boolean;
 
-  /**
-    Whether the application should be configured for the legacy "globals mode".
-    Under this mode, the Application object serves as a global namespace for all
-    classes.
-
-    ```javascript
-    import Application from '@ember/application';
-    import Component from '@ember/component';
-
-    let App = Application.create({
-      ...
-    });
-
-    App.Router.reopen({
-      location: 'none'
-    });
-
-    App.Router.map({
-      ...
-    });
-
-    App.MyComponent = Component.extend({
-      ...
-    });
-    ```
-
-    This flag also exposes other internal APIs that assumes the existence of
-    a special "default instance", like `App.__container__.lookup(...)`.
-
-    This option is currently not configurable, its value is derived from
-    the `autoboot` flag – disabling `autoboot` also implies opting-out of
-    globals mode support, although they are ultimately orthogonal concerns.
-
-    Some of the global modes features are already deprecated in 1.x. The
-    existence of this flag is to untangle the globals mode code paths from
-    the autoboot code paths, so that these legacy features can be reviewed
-    for deprecation/removal separately.
-
-    Forcing the (autoboot=true, _globalsMode=false) here and running the tests
-    would reveal all the places where we are still relying on these legacy
-    behavior internally (mostly just tests).
-
-    @property _globalsMode
-    @type Boolean
-    @default true
-    @private
-  */
-  declare _globalsMode: boolean;
-
   /**
     An array of application instances created by `buildInstance()`. Used
     internally to ensure that all instances get destroyed.
@@ -413,7 +364,6 @@ class Application extends Engine {
     this.customEvents ??= null;
     this.autoboot ??= true;
     this._document ??= hasDOM ? window.document : null;
-    this._globalsMode ??= true;
 
     if (DEBUG) {
       if (ENV.LOG_VERSION) {
@@ -429,13 +379,15 @@ class Application extends Engine {
     this._booted = false;
     this._applicationInstances = new Set();
 
-    this.autoboot = this._globalsMode = Boolean(this.autoboot);
-
-    if (this._globalsMode) {
-      this._prepareForGlobalsMode();
-    }
+    this.autoboot = Boolean(this.autoboot);
 
     if (this.autoboot) {
+      // Create subclass of Router for this Application instance.
+      // This is to ensure that someone reopening `App.Router` does not
+      // tamper with the default `Router`.
+      this.Router = (this.Router || Router).extend() as typeof Router;
+
+      this._buildDeprecatedInstance();
       this.waitForDOMReady();
     }
   }
@@ -489,26 +441,6 @@ class Application extends Engine {
 
   Router?: typeof Router;
 
-  /**
-    Enable the legacy globals mode by allowing this application to act
-    as a global namespace. See the docs on the `_globalsMode` property
-    for details.
-
-    Most of these features are already deprecated in 1.x, so we can
-    stop using them internally and try to remove them.
-
-    @private
-    @method _prepareForGlobalsMode
-  */
-  _prepareForGlobalsMode(): void {
-    // Create subclass of Router for this Application instance.
-    // This is to ensure that someone reopening `App.Router` does not
-    // tamper with the default `Router`.
-    this.Router = (this.Router || Router).extend() as typeof Router;
-
-    this._buildDeprecatedInstance();
-  }
-
   __deprecatedInstance__?: ApplicationInstance;
   __container__?: Container;
 
@@ -590,7 +522,7 @@ class Application extends Engine {
     ```javascript
     _autoBoot() {
       this.boot().then(() => {
-        let instance = (this._globalsMode) ? this.__deprecatedInstance__ : this.buildInstance();
+        let instance = this.__deprecatedInstance__;
         return instance.boot();
       }).then((instance) => {
         App.ready();
@@ -872,10 +804,10 @@ class Application extends Engine {
 
     assert(
       `Calling reset() on instances of \`Application\` is not
-            supported when globals mode is disabled; call \`visit()\` to
+            supported when autoboot is disabled; call \`visit()\` to
             create new \`ApplicationInstance\`s and dispose them
             via their \`destroy()\` method instead.`,
-      this._globalsMode && this.autoboot
+      this.autoboot
     );
 
     let instance = this.__deprecatedInstance__;
@@ -907,24 +839,12 @@ class Application extends Engine {
     assert('expected _bootResolver', this._bootResolver);
 
     try {
-      // TODO: Is this still needed for _globalsMode = false?
-
       // See documentation on `_autoboot()` for details
       if (this.autoboot) {
-        let instance;
-
-        if (this._globalsMode) {
-          // If we already have the __deprecatedInstance__ lying around, boot it to
-          // avoid unnecessary work
-          instance = this.__deprecatedInstance__;
-          assert('expected instance', instance);
-        } else {
-          // Otherwise, build an instance and boot it. This is currently unreachable,
-          // because we forced _globalsMode to === autoboot; but having this branch
-          // allows us to locally toggle that flag for weeding out legacy globals mode
-          // dependencies independently
-          instance = this.buildInstance();
-        }
+        // If we already have the __deprecatedInstance__ lying around, boot it to
+        // avoid unnecessary work
+        let instance = this.__deprecatedInstance__;
+        assert('expected instance', instance);
 
         instance._bootSync();
 

tests/docs/expected.js

@@ -24,7 +24,6 @@ module.exports = {
     '_fullyScopeQueryParams',
     '_getObjectsOnNamespaces',
     '_getQPMeta',
-    '_globalsMode',
     '_helpers',
     '_hydrateUnsuppliedQueryParams',
     '_initializersRan',
@@ -34,7 +33,6 @@ module.exports = {
     '_onLookup',
     '_options',
     '_optionsForQueryParam',
-    '_prepareForGlobalsMode',
     '_prepareQueryParams',
     '_pruneDefaultQueryParamValues',
     '_qp',