refactor: use lightweight token for injecting radio group

goldens/size-test.yaml

@@ -1 +1,2 @@
 material/list/nav-list: 130473
+material/radio/without-group: 121448

integration/size-test/material/radio/BUILD.bazel

@@ -0,0 +1,7 @@
+load("//integration/size-test:index.bzl", "size_test")
+
+size_test(
+    name = "without-group",
+    file = "without-group.ts",
+    deps = ["//src/material/radio"],
+)

integration/size-test/material/radio/without-group.ts

@@ -0,0 +1,23 @@
+import {Component, NgModule} from '@angular/core';
+import {MatRadioModule} from '@angular/material/radio';
+import {platformBrowser} from '@angular/platform-browser';
+
+/**
+ * Basic component using `MatRadioButton`. Doesn't use a `MatRadioGroup`, so the class
+ * should be tree-shaken away properly.
+ */
+@Component({
+  template: `
+    <mat-radio-button value="hello"></mat-radio-button>
+  `,
+})
+export class TestComponent {}
+
+@NgModule({
+  imports: [MatRadioModule],
+  declarations: [TestComponent],
+  bootstrap: [TestComponent],
+})
+export class AppModule {}
+
+platformBrowser().bootstrapModule(AppModule);

src/material-experimental/mdc-radio/radio.ts

@@ -16,6 +16,7 @@ import {
   ElementRef,
   forwardRef,
   Inject,
+  InjectionToken,
   OnDestroy,
   Optional,
   QueryList,
@@ -50,6 +51,14 @@ export const MAT_RADIO_GROUP_CONTROL_VALUE_ACCESSOR: any = {
   multi: true
 };
 
+/**
+ * Injection token that can be used to inject instances of `MatRadioGroup`. It serves as
+ * alternative token to the actual `MatRadioGroup` class which could cause unnecessary
+ * retention of the class and its component metadata.
+ */
+export const MAT_RADIO_GROUP =
+  new InjectionToken<_MatRadioGroupBase<_MatRadioButtonBase>>('MatRadioGroup');
+
 /** Configuration for the ripple animation. */
 const RIPPLE_ANIMATION_CONFIG: RippleAnimationConfig = {
   enterDuration: numbers.DEACTIVATION_TIMEOUT_MS,
@@ -62,7 +71,10 @@ const RIPPLE_ANIMATION_CONFIG: RippleAnimationConfig = {
 @Directive({
   selector: 'mat-radio-group',
   exportAs: 'matRadioGroup',
-  providers: [MAT_RADIO_GROUP_CONTROL_VALUE_ACCESSOR],
+  providers: [
+    MAT_RADIO_GROUP_CONTROL_VALUE_ACCESSOR,
+    {provide: MAT_RADIO_GROUP, useExisting: MatRadioGroup},
+  ],
   host: {
     'role': 'radiogroup',
     'class': 'mat-mdc-radio-group',
@@ -117,7 +129,7 @@ export class MatRadioButton extends _MatRadioButtonBase implements AfterViewInit
   _radioFoundation = new MDCRadioFoundation(this._radioAdapter);
   _classes: {[key: string]: boolean} = {};
 
-  constructor(@Optional() radioGroup: MatRadioGroup,
+  constructor(@Optional() @Inject(MAT_RADIO_GROUP) radioGroup: MatRadioGroup,
               elementRef: ElementRef,
               _changeDetector: ChangeDetectorRef,
               _focusMonitor: FocusMonitor,

src/material/radio/radio.ts

@@ -83,6 +83,14 @@ export class MatRadioChange {
     public value: any) {}
 }
 
+/**
+ * Injection token that can be used to inject instances of `MatRadioGroup`. It serves as
+ * alternative token to the actual `MatRadioGroup` class which could cause unnecessary
+ * retention of the class and its component metadata.
+ */
+export const MAT_RADIO_GROUP =
+    new InjectionToken<_MatRadioGroupBase<_MatRadioButtonBase>>('MatRadioGroup');
+
 /**
  * Base class with all of the `MatRadioGroup` functionality.
  * @docs-private
@@ -311,7 +319,10 @@ export abstract class _MatRadioGroupBase<T extends _MatRadioButtonBase> implemen
 @Directive({
   selector: 'mat-radio-group',
   exportAs: 'matRadioGroup',
-  providers: [MAT_RADIO_GROUP_CONTROL_VALUE_ACCESSOR],
+  providers: [
+    MAT_RADIO_GROUP_CONTROL_VALUE_ACCESSOR,
+    {provide: MAT_RADIO_GROUP, useExisting: MatRadioGroup},
+  ],
   host: {
     'role': 'radiogroup',
     'class': 'mat-radio-group',
@@ -475,14 +486,13 @@ export abstract class _MatRadioButtonBase extends _MatRadioButtonMixinBase imple
   /** The native `<input type=radio>` element */
   @ViewChild('input') _inputElement: ElementRef<HTMLInputElement>;
 
-  constructor(@Optional() radioGroup: _MatRadioGroupBase<_MatRadioButtonBase>,
+  constructor(radioGroup: _MatRadioGroupBase<_MatRadioButtonBase>,
               elementRef: ElementRef,
               protected _changeDetector: ChangeDetectorRef,
               private _focusMonitor: FocusMonitor,
               private _radioDispatcher: UniqueSelectionDispatcher,
-              @Optional() @Inject(ANIMATION_MODULE_TYPE) public _animationMode?: string,
-                @Optional() @Inject(MAT_RADIO_DEFAULT_OPTIONS)
-                private _providerOverride?: MatRadioDefaultOptions) {
+              public _animationMode?: string,
+              private _providerOverride?: MatRadioDefaultOptions) {
     super(elementRef);
 
     // Assertions. Ideally these should be stripped out by the compiler.
@@ -626,7 +636,7 @@ export abstract class _MatRadioButtonBase extends _MatRadioButtonMixinBase imple
   changeDetection: ChangeDetectionStrategy.OnPush,
 })
 export class MatRadioButton extends _MatRadioButtonBase {
-  constructor(@Optional() radioGroup: MatRadioGroup,
+  constructor(@Optional() @Inject(MAT_RADIO_GROUP) radioGroup: MatRadioGroup,
               elementRef: ElementRef,
               changeDetector: ChangeDetectorRef,
               focusMonitor: FocusMonitor,

tools/public_api_guard/material/radio.d.ts

@@ -37,7 +37,7 @@ export declare abstract class _MatRadioButtonBase extends _MatRadioButtonMixinBa
     static ngAcceptInputType_disabled: BooleanInput;
     static ngAcceptInputType_required: BooleanInput;
     static ɵdir: i0.ɵɵDirectiveDefWithMeta<_MatRadioButtonBase, never, never, { "id": "id"; "name": "name"; "ariaLabel": "aria-label"; "ariaLabelledby": "aria-labelledby"; "ariaDescribedby": "aria-describedby"; "checked": "checked"; "value": "value"; "labelPosition": "labelPosition"; "disabled": "disabled"; "required": "required"; "color": "color"; }, { "change": "change"; }, never>;
-    static ɵfac: i0.ɵɵFactoryDef<_MatRadioButtonBase, [{ optional: true; }, null, null, null, null, { optional: true; }, { optional: true; }]>;
+    static ɵfac: i0.ɵɵFactoryDef<_MatRadioButtonBase, never>;
 }
 
 export declare abstract class _MatRadioGroupBase<T extends _MatRadioButtonBase> implements AfterContentInit, ControlValueAccessor {
@@ -78,6 +78,8 @@ export declare const MAT_RADIO_DEFAULT_OPTIONS: InjectionToken<MatRadioDefaultOp
 
 export declare function MAT_RADIO_DEFAULT_OPTIONS_FACTORY(): MatRadioDefaultOptions;
 
+export declare const MAT_RADIO_GROUP: InjectionToken<_MatRadioGroupBase<_MatRadioButtonBase>>;
+
 export declare const MAT_RADIO_GROUP_CONTROL_VALUE_ACCESSOR: any;
 
 export declare class MatRadioButton extends _MatRadioButtonBase {