fix(form-field): enhance error handling for multiple form field controls

Currently, when multiple mat form fields are used together, the error is taken for the first control only, this take into consideration other controls too if they exist

Fixes #28887

Author: mistrykaran91

goldens/material/form-field/index.api.md

@@ -79,6 +79,8 @@ export class MatFormField implements FloatingLabelParent, AfterContentInit, Afte
     _forceDisplayInfixLabel(): boolean | 0;
     // (undocumented)
     _formFieldControl: MatFormFieldControl_2<any>;
+    // (undocumented)
+    _formFieldControls: QueryList<MatFormFieldControl_2<any>>;
     getConnectedOverlayOrigin(): ElementRef;
     getLabelId: i0.Signal<string | null>;
     _getSubscriptMessageType(): 'error' | 'hint';
@@ -121,6 +123,8 @@ export class MatFormField implements FloatingLabelParent, AfterContentInit, Afte
     ngOnDestroy(): void;
     // (undocumented)
     _notchedOutline: MatFormFieldNotchedOutline | undefined;
+    get otherFormFieldControls(): MatFormFieldControl_2<any>[];
+    get otherFormFieldControlsErrorState(): boolean;
     // (undocumented)
     _prefixChildren: QueryList<MatPrefix>;
     _refreshOutlineNotchWidth(): void;
@@ -139,7 +143,7 @@ export class MatFormField implements FloatingLabelParent, AfterContentInit, Afte
     // (undocumented)
     _textSuffixContainer: ElementRef<HTMLElement>;
     // (undocumented)
-    static ɵcmp: i0.ɵɵComponentDeclaration<MatFormField, "mat-form-field", ["matFormField"], { "hideRequiredMarker": { "alias": "hideRequiredMarker"; "required": false; }; "color": { "alias": "color"; "required": false; }; "floatLabel": { "alias": "floatLabel"; "required": false; }; "appearance": { "alias": "appearance"; "required": false; }; "subscriptSizing": { "alias": "subscriptSizing"; "required": false; }; "hintLabel": { "alias": "hintLabel"; "required": false; }; }, {}, ["_labelChild", "_formFieldControl", "_prefixChildren", "_suffixChildren", "_errorChildren", "_hintChildren"], ["mat-label", "[matPrefix], [matIconPrefix]", "[matTextPrefix]", "*", "[matTextSuffix]", "[matSuffix], [matIconSuffix]", "mat-error, [matError]", "mat-hint:not([align='end'])", "mat-hint[align='end']"], true, never>;
+    static ɵcmp: i0.ɵɵComponentDeclaration<MatFormField, "mat-form-field", ["matFormField"], { "hideRequiredMarker": { "alias": "hideRequiredMarker"; "required": false; }; "color": { "alias": "color"; "required": false; }; "floatLabel": { "alias": "floatLabel"; "required": false; }; "appearance": { "alias": "appearance"; "required": false; }; "subscriptSizing": { "alias": "subscriptSizing"; "required": false; }; "hintLabel": { "alias": "hintLabel"; "required": false; }; }, {}, ["_labelChild", "_formFieldControl", "_formFieldControls", "_prefixChildren", "_suffixChildren", "_errorChildren", "_hintChildren"], ["mat-label", "[matPrefix], [matIconPrefix]", "[matTextPrefix]", "*", "[matTextSuffix]", "[matSuffix], [matIconSuffix]", "mat-error, [matError]", "mat-hint:not([align='end'])", "mat-hint[align='end']"], true, never>;
     // (undocumented)
     static ɵfac: i0.ɵɵFactoryDeclaration<MatFormField, never>;
 }

goldens/material/input/index.api.md

@@ -72,6 +72,8 @@ export class MatFormField implements FloatingLabelParent, AfterContentInit, Afte
     _forceDisplayInfixLabel(): boolean | 0;
     // (undocumented)
     _formFieldControl: MatFormFieldControl<any>;
+    // (undocumented)
+    _formFieldControls: QueryList<MatFormFieldControl<any>>;
     getConnectedOverlayOrigin(): ElementRef;
     getLabelId: i0.Signal<string | null>;
     _getSubscriptMessageType(): 'error' | 'hint';
@@ -114,6 +116,8 @@ export class MatFormField implements FloatingLabelParent, AfterContentInit, Afte
     ngOnDestroy(): void;
     // (undocumented)
     _notchedOutline: MatFormFieldNotchedOutline | undefined;
+    get otherFormFieldControls(): MatFormFieldControl<any>[];
+    get otherFormFieldControlsErrorState(): boolean;
     // (undocumented)
     _prefixChildren: QueryList<MatPrefix>;
     _refreshOutlineNotchWidth(): void;
@@ -132,7 +136,7 @@ export class MatFormField implements FloatingLabelParent, AfterContentInit, Afte
     // (undocumented)
     _textSuffixContainer: ElementRef<HTMLElement>;
     // (undocumented)
-    static ɵcmp: i0.ɵɵComponentDeclaration<MatFormField, "mat-form-field", ["matFormField"], { "hideRequiredMarker": { "alias": "hideRequiredMarker"; "required": false; }; "color": { "alias": "color"; "required": false; }; "floatLabel": { "alias": "floatLabel"; "required": false; }; "appearance": { "alias": "appearance"; "required": false; }; "subscriptSizing": { "alias": "subscriptSizing"; "required": false; }; "hintLabel": { "alias": "hintLabel"; "required": false; }; }, {}, ["_labelChild", "_formFieldControl", "_prefixChildren", "_suffixChildren", "_errorChildren", "_hintChildren"], ["mat-label", "[matPrefix], [matIconPrefix]", "[matTextPrefix]", "*", "[matTextSuffix]", "[matSuffix], [matIconSuffix]", "mat-error, [matError]", "mat-hint:not([align='end'])", "mat-hint[align='end']"], true, never>;
+    static ɵcmp: i0.ɵɵComponentDeclaration<MatFormField, "mat-form-field", ["matFormField"], { "hideRequiredMarker": { "alias": "hideRequiredMarker"; "required": false; }; "color": { "alias": "color"; "required": false; }; "floatLabel": { "alias": "floatLabel"; "required": false; }; "appearance": { "alias": "appearance"; "required": false; }; "subscriptSizing": { "alias": "subscriptSizing"; "required": false; }; "hintLabel": { "alias": "hintLabel"; "required": false; }; }, {}, ["_labelChild", "_formFieldControl", "_formFieldControls", "_prefixChildren", "_suffixChildren", "_errorChildren", "_hintChildren"], ["mat-label", "[matPrefix], [matIconPrefix]", "[matTextPrefix]", "*", "[matTextSuffix]", "[matSuffix], [matIconSuffix]", "mat-error, [matError]", "mat-hint:not([align='end'])", "mat-hint[align='end']"], true, never>;
     // (undocumented)
     static ɵfac: i0.ɵɵFactoryDeclaration<MatFormField, never>;
 }

goldens/material/select/index.api.md

@@ -95,6 +95,8 @@ export class MatFormField implements FloatingLabelParent, AfterContentInit, Afte
     _forceDisplayInfixLabel(): boolean | 0;
     // (undocumented)
     _formFieldControl: MatFormFieldControl_2<any>;
+    // (undocumented)
+    _formFieldControls: QueryList<MatFormFieldControl_2<any>>;
     getConnectedOverlayOrigin(): ElementRef;
     getLabelId: i0.Signal<string | null>;
     _getSubscriptMessageType(): 'error' | 'hint';
@@ -137,6 +139,8 @@ export class MatFormField implements FloatingLabelParent, AfterContentInit, Afte
     ngOnDestroy(): void;
     // (undocumented)
     _notchedOutline: MatFormFieldNotchedOutline | undefined;
+    get otherFormFieldControls(): MatFormFieldControl_2<any>[];
+    get otherFormFieldControlsErrorState(): boolean;
     // (undocumented)
     _prefixChildren: QueryList<MatPrefix>;
     _refreshOutlineNotchWidth(): void;
@@ -155,7 +159,7 @@ export class MatFormField implements FloatingLabelParent, AfterContentInit, Afte
     // (undocumented)
     _textSuffixContainer: ElementRef<HTMLElement>;
     // (undocumented)
-    static ɵcmp: i0.ɵɵComponentDeclaration<MatFormField, "mat-form-field", ["matFormField"], { "hideRequiredMarker": { "alias": "hideRequiredMarker"; "required": false; }; "color": { "alias": "color"; "required": false; }; "floatLabel": { "alias": "floatLabel"; "required": false; }; "appearance": { "alias": "appearance"; "required": false; }; "subscriptSizing": { "alias": "subscriptSizing"; "required": false; }; "hintLabel": { "alias": "hintLabel"; "required": false; }; }, {}, ["_labelChild", "_formFieldControl", "_prefixChildren", "_suffixChildren", "_errorChildren", "_hintChildren"], ["mat-label", "[matPrefix], [matIconPrefix]", "[matTextPrefix]", "*", "[matTextSuffix]", "[matSuffix], [matIconSuffix]", "mat-error, [matError]", "mat-hint:not([align='end'])", "mat-hint[align='end']"], true, never>;
+    static ɵcmp: i0.ɵɵComponentDeclaration<MatFormField, "mat-form-field", ["matFormField"], { "hideRequiredMarker": { "alias": "hideRequiredMarker"; "required": false; }; "color": { "alias": "color"; "required": false; }; "floatLabel": { "alias": "floatLabel"; "required": false; }; "appearance": { "alias": "appearance"; "required": false; }; "subscriptSizing": { "alias": "subscriptSizing"; "required": false; }; "hintLabel": { "alias": "hintLabel"; "required": false; }; }, {}, ["_labelChild", "_formFieldControl", "_formFieldControls", "_prefixChildren", "_suffixChildren", "_errorChildren", "_hintChildren"], ["mat-label", "[matPrefix], [matIconPrefix]", "[matTextPrefix]", "*", "[matTextSuffix]", "[matSuffix], [matIconSuffix]", "mat-error, [matError]", "mat-hint:not([align='end'])", "mat-hint[align='end']"], true, never>;
     // (undocumented)
     static ɵfac: i0.ɵɵFactoryDeclaration<MatFormField, never>;
 }

src/material/chips/chip-grid.spec.ts

@@ -867,6 +867,50 @@ describe('MatChipGrid', () => {
     });
   });
 
+  describe('error message when multiple form field controls', () => {
+    let fixture: ComponentFixture<ChipGridWithMultipleControls>;
+    let errorTestComponent: ChipGridWithMultipleControls;
+    let containerEl: HTMLElement;
+    let chipGridEl: HTMLElement;
+
+    beforeEach(fakeAsync(() => {
+      fixture = createComponent(ChipGridWithMultipleControls);
+      flush();
+      fixture.detectChanges();
+
+      errorTestComponent = fixture.componentInstance;
+      containerEl = fixture.debugElement.query(By.css('mat-form-field'))!.nativeElement;
+      chipGridEl = fixture.debugElement.query(By.css('mat-chip-grid'))!.nativeElement;
+    }));
+
+    it('should display an error message when the grid is touched and invalid when multiple controls in mat form field', fakeAsync(() => {
+      expect(errorTestComponent.chipCtrl.invalid)
+        .withContext('Expected form control to be invalid')
+        .toBe(true);
+      expect(containerEl.querySelectorAll('mat-error').length)
+        .withContext('Expected no error message')
+        .toBe(0);
+
+      expect(containerEl.classList)
+        .withContext('Expected container not to have the invalid CSS class.')
+        .not.toContain('mat-form-field-invalid');
+
+      errorTestComponent.chipCtrl.markAsTouched();
+      fixture.detectChanges();
+      tick();
+
+      expect(containerEl.classList)
+        .withContext('Expected container to have the invalid CSS class.')
+        .toContain('mat-form-field-invalid');
+      expect(containerEl.querySelectorAll('mat-error').length)
+        .withContext('Expected one error message to have been rendered.')
+        .toBe(1);
+      expect(chipGridEl.getAttribute('aria-invalid'))
+        .withContext('Expected aria-invalid to be set to "true".')
+        .toBe('true');
+    }));
+  });
+
   describe('error messages', () => {
     let fixture: ComponentFixture<ChipGridWithFormErrorMessages>;
     let errorTestComponent: ChipGridWithFormErrorMessages;
@@ -1228,3 +1272,36 @@ class ChipGridWithRemove {
     this.chips.splice(event.chip.value, 1);
   }
 }
+
+@Component({
+  template: `
+    <mat-form-field>
+    <input
+          matInput
+          type="text"
+          placeholder="New item..."
+          [matChipInputFor]="chipGrid"
+        />
+
+      <mat-chip-grid #chipGrid  required [formControl]="chipCtrl">
+        @for (i of chips; track i) {
+          <mat-chip-row [value]="i" >
+            Chip {{i + 1}}
+            <span matChipRemove>Remove</span>
+          </mat-chip-row>
+        }
+      </mat-chip-grid>
+
+      <mat-error data-test-id="errors">
+            @if (chipCtrl.errors?.['required']) {
+              {{ 'Error occurs' }}
+            }
+          </mat-error>
+    </mat-form-field>
+  `,
+  standalone: false,
+})
+class ChipGridWithMultipleControls {
+  chipCtrl = new FormControl();
+  chips = [0, 1, 2, 3, 4];
+}

src/material/form-field/form-field.html

@@ -42,7 +42,7 @@
   [class.mdc-text-field--outlined]="_hasOutline()"
   [class.mdc-text-field--no-label]="!_hasFloatingLabel()"
   [class.mdc-text-field--disabled]="_control.disabled"
-  [class.mdc-text-field--invalid]="_control.errorState"
+  [class.mdc-text-field--invalid]="_control.errorState || otherFormFieldControlsErrorState"
   (click)="_control.onContainerClick($event)"
 >
   @if (!_hasOutline() && !_control.disabled) {
@@ -96,20 +96,20 @@
 </div>
 
 <div
-    class="mat-mdc-form-field-subscript-wrapper mat-mdc-form-field-bottom-align"
-    [class.mat-mdc-form-field-subscript-dynamic-size]="subscriptSizing === 'dynamic'"
->
+  class="mat-mdc-form-field-subscript-wrapper mat-mdc-form-field-bottom-align"
+  [class.mat-mdc-form-field-subscript-dynamic-size]="subscriptSizing === 'dynamic'">
   @let subscriptMessageType = _getSubscriptMessageType();
 
   <!-- 
     Use a single permanent wrapper for both hints and errors so aria-live works correctly,
     as having it appear post render will not consistently work. We also do not want to add
     additional divs as it causes styling regressions.
     -->
-  <div aria-atomic="true" aria-live="polite" 
-      [class.mat-mdc-form-field-error-wrapper]="subscriptMessageType === 'error'"
-      [class.mat-mdc-form-field-hint-wrapper]="subscriptMessageType === 'hint'"
-    >
+  <div
+    aria-atomic="true"
+    aria-live="polite"
+    [class.mat-mdc-form-field-error-wrapper]="subscriptMessageType === 'error'"
+    [class.mat-mdc-form-field-hint-wrapper]="subscriptMessageType === 'hint'">
     @switch (subscriptMessageType) {
       @case ('error') {
         <ng-content select="mat-error, [matError]"></ng-content>

src/material/form-field/form-field.ts

@@ -149,7 +149,7 @@ interface MatFormFieldControl<T> extends _MatFormFieldControl<T> {}
     // Note that these classes reuse the same names as the non-MDC version, because they can be
     // considered a public API since custom form controls may use them to style themselves.
     // See https://github.com/angular/components/pull/20502#discussion_r486124901.
-    '[class.mat-form-field-invalid]': '_control.errorState',
+    '[class.mat-form-field-invalid]': '_control.errorState || otherFormFieldControlsErrorState',
     '[class.mat-form-field-disabled]': '_control.disabled',
     '[class.mat-form-field-autofilled]': '_control.autofilled',
     '[class.mat-form-field-appearance-fill]': 'appearance == "fill"',
@@ -219,6 +219,9 @@ export class MatFormField
   });
 
   @ContentChild(_MatFormFieldControl) _formFieldControl: MatFormFieldControl<any>;
+  @ContentChildren(_MatFormFieldControl, {descendants: true}) _formFieldControls: QueryList<
+    MatFormFieldControl<any>
+  >;
   @ContentChildren(MAT_PREFIX, {descendants: true}) _prefixChildren: QueryList<MatPrefix>;
   @ContentChildren(MAT_SUFFIX, {descendants: true}) _suffixChildren: QueryList<MatSuffix>;
   @ContentChildren(MAT_ERROR, {descendants: true}) _errorChildren: QueryList<MatError>;
@@ -327,12 +330,23 @@ export class MatFormField
     this._explicitFormFieldControl = value;
   }
 
+  /** Gets the other form field controls if any */
+  get otherFormFieldControls(): MatFormFieldControl<any>[] {
+    return this._formFieldControls.filter(control => control.id !== this._control.id);
+  }
+
+  /** Gets the error state of other form field controls if any */
+  get otherFormFieldControlsErrorState(): boolean {
+    return this.otherFormFieldControls.some(control => control.errorState);
+  }
+
   private _destroyed = new Subject<void>();
   private _isFocused: boolean | null = null;
   private _explicitFormFieldControl: MatFormFieldControl<any>;
   private _previousControl: MatFormFieldControl<unknown> | null = null;
   private _previousControlValidatorFn: ValidatorFn | null = null;
   private _stateChanges: Subscription | undefined;
+  private _otherControlStateChanges: Subscription | undefined;
   private _valueChanges: Subscription | undefined;
   private _describedByChanges: Subscription | undefined;
   protected readonly _animationsDisabled = _animationsDisabled();
@@ -412,6 +426,7 @@ export class MatFormField
   ngOnDestroy() {
     this._outlineLabelOffsetResizeObserver?.disconnect();
     this._stateChanges?.unsubscribe();
+    this._otherControlStateChanges?.unsubscribe();
     this._valueChanges?.unsubscribe();
     this._describedByChanges?.unsubscribe();
     this._destroyed.next();
@@ -466,6 +481,16 @@ export class MatFormField
       this._changeDetectorRef.markForCheck();
     });
 
+    if (this.otherFormFieldControls.length) {
+      this._otherControlStateChanges?.unsubscribe();
+      this.otherFormFieldControls.map(control => {
+        const subscription = control.stateChanges.subscribe(() =>
+          this._changeDetectorRef.markForCheck(),
+        );
+        this._otherControlStateChanges?.add(subscription);
+      });
+    }
+
     // Updating the `aria-describedby` touches the DOM. Only do it if it actually needs to change.
     this._describedByChanges?.unsubscribe();
     this._describedByChanges = control.stateChanges
@@ -632,7 +657,9 @@ export class MatFormField
 
   /** Gets the type of subscript message to render (error or hint). */
   _getSubscriptMessageType(): 'error' | 'hint' {
-    return this._errorChildren && this._errorChildren.length > 0 && this._control.errorState
+    return this._errorChildren &&
+      this._errorChildren.length > 0 &&
+      (this._control.errorState || this.otherFormFieldControlsErrorState)
       ? 'error'
       : 'hint';
   }