fix(stepper): unable to skip step if completed value is overwritten

Currently we allow for the `completed` value of a step to be overwritten, however setting it to `true` still won't allow the user to skip the step, because the `interacted` flag won't be flipped if they haven't been on a particular step before.

Fixes #15310.

Author: crisbeto

src/cdk/stepper/stepper.ts

@@ -9,7 +9,8 @@
 import {FocusableOption, FocusKeyManager} from '@angular/cdk/a11y';
 import {Direction, Directionality} from '@angular/cdk/bidi';
 import {coerceBooleanProperty, coerceNumberProperty} from '@angular/cdk/coercion';
-import {END, ENTER, HOME, SPACE, hasModifierKey} from '@angular/cdk/keycodes';
+import {END, ENTER, hasModifierKey, HOME, SPACE} from '@angular/cdk/keycodes';
+import {DOCUMENT} from '@angular/common';
 import {
   AfterViewInit,
   ChangeDetectionStrategy,
@@ -18,10 +19,11 @@ import {
   ContentChild,
   ContentChildren,
   Directive,
-  EventEmitter,
   ElementRef,
+  EventEmitter,
   forwardRef,
   Inject,
+  InjectionToken,
   Input,
   OnChanges,
   OnDestroy,
@@ -31,13 +33,12 @@ import {
   TemplateRef,
   ViewChild,
   ViewEncapsulation,
-  InjectionToken,
 } from '@angular/core';
-import {DOCUMENT} from '@angular/common';
-import {CdkStepLabel} from './step-label';
-import {Observable, Subject, of as obaservableOf} from 'rxjs';
+import {Observable, of as obaservableOf, Subject} from 'rxjs';
 import {startWith, takeUntil} from 'rxjs/operators';
+
 import {CdkStepHeader} from './step-header';
+import {CdkStepLabel} from './step-label';
 
 /** Used to generate unique ID for each stepper component. */
 let nextId = 0;
@@ -46,10 +47,10 @@ let nextId = 0;
  * Position state of the content of each step in stepper that is used for transitioning
  * the content into correct position upon step selection change.
  */
-export type StepContentPositionState = 'previous' | 'current' | 'next';
+export type StepContentPositionState = 'previous'|'current'|'next';
 
 /** Possible orientation of a stepper. */
-export type StepperOrientation = 'horizontal' | 'vertical';
+export type StepperOrientation = 'horizontal'|'vertical';
 
 /** Change event emitted on selection changes. */
 export class StepperSelectionEvent {
@@ -67,7 +68,7 @@ export class StepperSelectionEvent {
 }
 
 /** The state of each step. */
-export type StepState = 'number' | 'edit' | 'done' | 'error' | string;
+export type StepState = 'number'|'edit'|'done'|'error'|string;
 
 /** Enum to represent the different states of the steps. */
 export const STEP_STATE = {
@@ -78,8 +79,7 @@ export const STEP_STATE = {
 };
 
 /** InjectionToken that can be used to specify the global stepper options. */
-export const STEPPER_GLOBAL_OPTIONS =
-  new InjectionToken<StepperOptions>('STEPPER_GLOBAL_OPTIONS');
+export const STEPPER_GLOBAL_OPTIONS = new InjectionToken<StepperOptions>('STEPPER_GLOBAL_OPTIONS');
 
 /**
  * InjectionToken that can be used to specify the global stepper options.
@@ -124,12 +124,7 @@ export class CdkStep implements OnChanges {
   @ViewChild(TemplateRef) content: TemplateRef<any>;
 
   /** The top level abstract control of the step. */
-  @Input() stepControl: {
-    valid: boolean;
-    invalid: boolean;
-    pending: boolean;
-    reset: () => void;
-  };
+  @Input() stepControl: {valid: boolean; invalid: boolean; pending: boolean; reset: () => void};
 
   /** Whether user has seen the expanded step content or not. */
   interacted = false;
@@ -154,15 +149,19 @@ export class CdkStep implements OnChanges {
 
   /** Whether the user can return to this step once it has been marked as completed. */
   @Input()
-  get editable(): boolean { return this._editable; }
+  get editable(): boolean {
+    return this._editable;
+  }
   set editable(value: boolean) {
     this._editable = coerceBooleanProperty(value);
   }
   private _editable = true;
 
   /** Whether the completion of step is optional. */
   @Input()
-  get optional(): boolean { return this._optional; }
+  get optional(): boolean {
+    return this._optional;
+  }
   set optional(value: boolean) {
     this._optional = coerceBooleanProperty(value);
   }
@@ -171,12 +170,12 @@ export class CdkStep implements OnChanges {
   /** Whether step is marked as completed. */
   @Input()
   get completed(): boolean {
-    return this._customCompleted == null ? this._getDefaultCompleted() : this._customCompleted;
+    return this._completedOverride == null ? this._getDefaultCompleted() : this._completedOverride;
   }
   set completed(value: boolean) {
-    this._customCompleted = coerceBooleanProperty(value);
+    this._completedOverride = coerceBooleanProperty(value);
   }
-  private _customCompleted: boolean | null = null;
+  _completedOverride: boolean|null = null;
 
   private _getDefaultCompleted() {
     return this.stepControl ? this.stepControl.valid && this.interacted : this.interacted;
@@ -190,16 +189,16 @@ export class CdkStep implements OnChanges {
   set hasError(value: boolean) {
     this._customError = coerceBooleanProperty(value);
   }
-  private _customError: boolean | null = null;
+  private _customError: boolean|null = null;
 
   private _getDefaultError() {
     return this.stepControl && this.stepControl.invalid && this.interacted;
   }
 
   /** @breaking-change 8.0.0 remove the `?` after `stepperOptions` */
   constructor(
-    @Inject(forwardRef(() => CdkStepper)) private _stepper: CdkStepper,
-    @Optional() @Inject(STEPPER_GLOBAL_OPTIONS) stepperOptions?: StepperOptions) {
+      @Inject(forwardRef(() => CdkStepper)) private _stepper: CdkStepper,
+      @Optional() @Inject(STEPPER_GLOBAL_OPTIONS) stepperOptions?: StepperOptions) {
     this._stepperOptions = stepperOptions ? stepperOptions : {};
     this._displayDefaultIndicatorType = this._stepperOptions.displayDefaultIndicatorType !== false;
     this._showError = !!this._stepperOptions.showError;
@@ -214,8 +213,8 @@ export class CdkStep implements OnChanges {
   reset(): void {
     this.interacted = false;
 
-    if (this._customCompleted != null) {
-      this._customCompleted = false;
+    if (this._completedOverride != null) {
+      this._completedOverride = false;
     }
 
     if (this._customError != null) {
@@ -249,7 +248,7 @@ export class CdkStepper implements AfterViewInit, OnDestroy {
    * @breaking-change 8.0.0 Remove `| undefined` once the `_document`
    * constructor param is required.
    */
-  private _document: Document | undefined;
+  private _document: Document|undefined;
 
   /**
    * The list of step components that the stepper is holding.
@@ -259,7 +258,7 @@ export class CdkStepper implements AfterViewInit, OnDestroy {
   @ContentChildren(CdkStep) _steps: QueryList<CdkStep>;
 
   /** The list of step components that the stepper is holding. */
-  get steps():  QueryList<CdkStep> {
+  get steps(): QueryList<CdkStep> {
     return this._steps;
   }
 
@@ -272,13 +271,19 @@ export class CdkStepper implements AfterViewInit, OnDestroy {
 
   /** Whether the validity of previous steps should be checked or not. */
   @Input()
-  get linear(): boolean { return this._linear; }
-  set linear(value: boolean) { this._linear = coerceBooleanProperty(value); }
+  get linear(): boolean {
+    return this._linear;
+  }
+  set linear(value: boolean) {
+    this._linear = coerceBooleanProperty(value);
+  }
   private _linear = false;
 
   /** The index of the selected step. */
   @Input()
-  get selectedIndex() { return this._selectedIndex; }
+  get selectedIndex() {
+    return this._selectedIndex;
+  }
   set selectedIndex(index: number) {
     const newIndex = coerceNumberProperty(index);
 
@@ -288,8 +293,7 @@ export class CdkStepper implements AfterViewInit, OnDestroy {
         throw Error('cdkStepper: Cannot assign out-of-bounds value to `selectedIndex`.');
       }
 
-      if (this._selectedIndex != newIndex &&
-          !this._anyControlsInvalidOrPending(newIndex) &&
+      if (this._selectedIndex != newIndex && !this._anyControlsInvalidOrPending(newIndex) &&
           (newIndex >= this._selectedIndex || this.steps.toArray()[newIndex].editable)) {
         this._updateSelectedItemIndex(index);
       }
@@ -310,20 +314,18 @@ export class CdkStepper implements AfterViewInit, OnDestroy {
   }
 
   /** Event emitted when the selected step has changed. */
-  @Output() selectionChange: EventEmitter<StepperSelectionEvent>
-      = new EventEmitter<StepperSelectionEvent>();
+  @Output()
+  selectionChange: EventEmitter<StepperSelectionEvent> = new EventEmitter<StepperSelectionEvent>();
 
   /** Used to track unique ID for each stepper component. */
   _groupId: number;
 
   protected _orientation: StepperOrientation = 'horizontal';
 
   constructor(
-    @Optional() private _dir: Directionality,
-    private _changeDetectorRef: ChangeDetectorRef,
-    // @breaking-change 8.0.0 `_elementRef` and `_document` parameters to become required.
-    private _elementRef?: ElementRef<HTMLElement>,
-    @Inject(DOCUMENT) _document?: any) {
+      @Optional() private _dir: Directionality, private _changeDetectorRef: ChangeDetectorRef,
+      // @breaking-change 8.0.0 `_elementRef` and `_document` parameters to become required.
+      private _elementRef?: ElementRef<HTMLElement>, @Inject(DOCUMENT) _document?: any) {
     this._groupId = nextId++;
     this._document = _document;
   }
@@ -333,12 +335,12 @@ export class CdkStepper implements AfterViewInit, OnDestroy {
     // extend this one might have them as view chidren. We initialize the keyboard handling in
     // AfterViewInit so we're guaranteed for both view and content children to be defined.
     this._keyManager = new FocusKeyManager<FocusableOption>(this._stepHeader)
-      .withWrap()
-      .withVerticalOrientation(this._orientation === 'vertical');
+                           .withWrap()
+                           .withVerticalOrientation(this._orientation === 'vertical');
 
-    (this._dir ? this._dir.change as Observable<Direction> : obaservableOf<Direction>())
-      .pipe(startWith(this._layoutDirection()), takeUntil(this._destroyed))
-      .subscribe(direction => this._keyManager.withHorizontalOrientation(direction));
+    (this._dir ? (this._dir.change as Observable<Direction>) : obaservableOf<Direction>())
+        .pipe(startWith(this._layoutDirection()), takeUntil(this._destroyed))
+        .subscribe(direction => this._keyManager.withHorizontalOrientation(direction));
 
     this._keyManager.updateActiveItemIndex(this._selectedIndex);
 
@@ -402,9 +404,8 @@ export class CdkStepper implements AfterViewInit, OnDestroy {
     const step = this.steps.toArray()[index];
     const isCurrentStep = this._isCurrentStep(index);
 
-    return step._displayDefaultIndicatorType
-      ? this._getDefaultIndicatorLogic(step, isCurrentStep)
-      : this._getGuidelineLogic(step, isCurrentStep, state);
+    return step._displayDefaultIndicatorType ? this._getDefaultIndicatorLogic(step, isCurrentStep) :
+                                               this._getGuidelineLogic(step, isCurrentStep, state);
   }
 
   private _getDefaultIndicatorLogic(step: CdkStep, isCurrentStep: boolean): StepState {
@@ -418,9 +419,7 @@ export class CdkStepper implements AfterViewInit, OnDestroy {
   }
 
   private _getGuidelineLogic(
-    step: CdkStep,
-    isCurrentStep: boolean,
-    state: StepState = STEP_STATE.NUMBER): StepState {
+      step: CdkStep, isCurrentStep: boolean, state: StepState = STEP_STATE.NUMBER): StepState {
     if (step._showError && step.hasError && !isCurrentStep) {
       return STEP_STATE.ERROR;
     } else if (step.completed && !isCurrentStep) {
@@ -491,10 +490,9 @@ export class CdkStepper implements AfterViewInit, OnDestroy {
     if (this._linear && index >= 0) {
       return steps.slice(0, index).some(step => {
         const control = step.stepControl;
-        const isIncomplete = control ?
-            (control.invalid || control.pending || !step.interacted) :
-            !step.completed;
-        return isIncomplete && !step.optional;
+        const isIncomplete =
+            control ? (control.invalid || control.pending || !step.interacted) : !step.completed;
+        return isIncomplete && !step.optional && !step._completedOverride;
       });
     }
 

src/lib/stepper/stepper.spec.ts

@@ -718,6 +718,27 @@ describe('MatStepper', () => {
       expect(steps[2].completed).toBe(true,
           'Expected third step to be considered complete when doing a run after a reset.');
     });
+
+    it('should be able to skip past the current step if a custom `completed` value is set', () => {
+      expect(testComponent.oneGroup.get('oneCtrl')!.value).toBe('');
+      expect(testComponent.oneGroup.get('oneCtrl')!.valid).toBe(false);
+      expect(testComponent.oneGroup.valid).toBe(false);
+      expect(stepperComponent.selectedIndex).toBe(0);
+
+      const nextButtonNativeEl = fixture.debugElement
+          .queryAll(By.directive(MatStepperNext))[0].nativeElement;
+      nextButtonNativeEl.click();
+      fixture.detectChanges();
+
+      expect(stepperComponent.selectedIndex).toBe(0);
+
+      stepperComponent.steps.first.completed = true;
+      nextButtonNativeEl.click();
+      fixture.detectChanges();
+
+      expect(testComponent.oneGroup.valid).toBe(false);
+      expect(stepperComponent.selectedIndex).toBe(1);
+    });
   });
 
   describe('linear stepper with a pre-defined selectedIndex', () => {

tools/public_api_guard/cdk/stepper.d.ts

@@ -1,4 +1,5 @@
 export declare class CdkStep implements OnChanges {
+    _completedOverride: boolean | null;
     _displayDefaultIndicatorType: boolean;
     _showError: boolean;
     ariaLabel: string;