No longer test EXTEND_PROTOYPES .. the last usage is removed in >= 6.0

.github/workflows/ci.yml

@@ -98,13 +98,6 @@ jobs:
           - name: "Production build, with optional features"
             BUILD: "production"
             ENABLE_OPTIONAL_FEATURES: "true"
-          - name: "Extend prototypes"
-            EXTEND_PROTOTYPES: "true"
-            RAISE_ON_DEPRECATION: "false"
-          - name: "Extend prototypes, with optional features"
-            EXTEND_PROTOTYPES: "true"
-            ENABLE_OPTIONAL_FEATURES: "true"
-            RAISE_ON_DEPRECATION: "false"
 
     steps:
       - uses: actions/checkout@v4
@@ -115,7 +108,6 @@ jobs:
         env:
           ALL_DEPRECATIONS_ENABLED: ${{ matrix.ALL_DEPRECATIONS_ENABLED }}
           OVERRIDE_DEPRECATION_VERSION: ${{ matrix.OVERRIDE_DEPRECATION_VERSION }}
-          EXTEND_PROTOTYPES: ${{ matrix.EXTEND_PROTOTYPES }}
           ENABLE_OPTIONAL_FEATURES: ${{ matrix.ENABLE_OPTIONAL_FEATURES }}
           RAISE_ON_DEPRECATION: ${{ matrix.RAISE_ON_DEPRECATION }}
 

bin/run-tests.js

@@ -18,10 +18,6 @@ const variants = [
   // hit its "until" version, the tests for it will behave correctly.
   'OVERRIDE_DEPRECATION_VERSION',
 
-  // This enables the legacy Ember feature that causes Ember to extend built-in
-  // platform features like Array.
-  'EXTEND_PROTOTYPES',
-
   // This enables all canary feature flags for unreleased feature within Ember
   // itself.
   'ENABLE_OPTIONAL_FEATURES',

index.html

@@ -24,9 +24,6 @@
         EmberENV.__test_hook_count__ += object;
       });
 
-      // Handle extending prototypes
-      EmberENV['EXTEND_PROTOTYPES'] = !!QUnit.urlParams.EXTEND_PROTOTYPES;
-
       // Handle testing feature flags
       if (QUnit.urlParams.ENABLE_OPTIONAL_FEATURES) {
         EmberENV.ENABLE_OPTIONAL_FEATURES = true;

packages/@ember/-internals/environment/lib/env.ts

@@ -26,11 +26,11 @@ export const ENV = {
     @type Boolean
     @default true
     @for EmberENV
-    @public
+    @private
     @deprecated in v5.10
   */
   EXTEND_PROTOTYPES: {
-    Array: true,
+    Array: false,
   },
 
   /**

packages/@ember/array/index.ts

@@ -2094,34 +2094,20 @@ NativeArray = NativeArray.without(...ignore);
 
 let A: <T>(arr?: Array<T>) => NativeArray<T>;
 
-if (ENV.EXTEND_PROTOTYPES.Array) {
-  NativeArray.apply(Array.prototype, true);
-
-  A = function <T>(this: unknown, arr?: Array<T>) {
-    assert(
-      'You cannot create an Ember Array with `new A()`, please update to calling A as a function: `A()`',
-      !(this instanceof A)
-    );
-
-    // SAFTEY: Since we are extending prototypes all true native arrays are Ember NativeArrays
-    return (arr || []) as NativeArray<T>;
-  };
-} else {
-  A = function <T>(this: unknown, arr?: Array<T>) {
-    assert(
-      'You cannot create an Ember Array with `new A()`, please update to calling A as a function: `A()`',
-      !(this instanceof A)
-    );
-
-    if (isEmberArray(arr)) {
-      // SAFETY: If it's a true native array and it is also an EmberArray then it should be an Ember NativeArray
-      return arr as unknown as NativeArray<T>;
-    } else {
-      // SAFETY: This will return an NativeArray but TS can't infer that.
-      return NativeArray.apply(arr ?? []) as NativeArray<T>;
-    }
-  };
-}
+A = function <T>(this: unknown, arr?: Array<T>) {
+  assert(
+    'You cannot create an Ember Array with `new A()`, please update to calling A as a function: `A()`',
+    !(this instanceof A)
+  );
+
+  if (isEmberArray(arr)) {
+    // SAFETY: If it's a true native array and it is also an EmberArray then it should be an Ember NativeArray
+    return arr as unknown as NativeArray<T>;
+  } else {
+    // SAFETY: This will return an NativeArray but TS can't infer that.
+    return NativeArray.apply(arr ?? []) as NativeArray<T>;
+  }
+};
 
 export { A, NativeArray, MutableArray };