fix(calendar): not reacting to min/max boundary changes (#7234)

Fixes the calendar not re-rendering when the `minDate`, `maxDate` or `dateFilter` change. The issue was due to the fact that the `minDate`, `maxDate` and `dateFilter` weren't being passed down to the views via `@Input`.

Fixes #7202.

src/lib/datepicker/calendar.spec.ts

@@ -528,6 +528,57 @@ describe('MatCalendar', () => {
 
       expect(calendarInstance._activeDate).toEqual(new Date(2018, JAN, 1));
     });
+
+    it('should re-render the month view when the minDate changes', () => {
+      fixture.detectChanges();
+      spyOn(calendarInstance.monthView, '_init').and.callThrough();
+
+      testComponent.minDate = new Date(2017, NOV, 1);
+      fixture.detectChanges();
+
+      expect(calendarInstance.monthView._init).toHaveBeenCalled();
+    });
+
+    it('should re-render the month view when the maxDate changes', () => {
+      fixture.detectChanges();
+      spyOn(calendarInstance.monthView, '_init').and.callThrough();
+
+      testComponent.maxDate = new Date(2017, DEC, 1);
+      fixture.detectChanges();
+
+      expect(calendarInstance.monthView._init).toHaveBeenCalled();
+    });
+
+    it('should re-render the year view when the minDate changes', () => {
+      fixture.detectChanges();
+      const periodButton =
+          calendarElement.querySelector('.mat-calendar-period-button') as HTMLElement;
+      periodButton.click();
+      fixture.detectChanges();
+
+      spyOn(calendarInstance.yearView, '_init').and.callThrough();
+
+      testComponent.minDate = new Date(2017, NOV, 1);
+      fixture.detectChanges();
+
+      expect(calendarInstance.yearView._init).toHaveBeenCalled();
+    });
+
+    it('should re-render the year view when the maxDate changes', () => {
+      fixture.detectChanges();
+      const periodButton =
+          calendarElement.querySelector('.mat-calendar-period-button') as HTMLElement;
+      periodButton.click();
+      fixture.detectChanges();
+
+      spyOn(calendarInstance.yearView, '_init').and.callThrough();
+
+      testComponent.maxDate = new Date(2017, DEC, 1);
+      fixture.detectChanges();
+
+      expect(calendarInstance.yearView._init).toHaveBeenCalled();
+    });
+
   });
 
   describe('calendar with date filter', () => {

src/lib/datepicker/calendar.ts

@@ -31,6 +31,9 @@ import {
   Optional,
   Output,
   ViewEncapsulation,
+  ViewChild,
+  OnChanges,
+  SimpleChanges,
 } from '@angular/core';
 import {DateAdapter, MAT_DATE_FORMATS, MatDateFormats} from '@angular/material/core';
 import {first} from 'rxjs/operator/first';
@@ -38,6 +41,8 @@ import {Subscription} from 'rxjs/Subscription';
 import {coerceDateProperty} from './coerce-date-property';
 import {createMissingDateImplError} from './datepicker-errors';
 import {MatDatepickerIntl} from './datepicker-intl';
+import {MatMonthView} from './month-view';
+import {MatYearView} from './year-view';
 
 
 /**
@@ -56,7 +61,7 @@ import {MatDatepickerIntl} from './datepicker-intl';
   preserveWhitespaces: false,
   changeDetection: ChangeDetectionStrategy.OnPush,
 })
-export class MatCalendar<D> implements AfterContentInit, OnDestroy {
+export class MatCalendar<D> implements AfterContentInit, OnDestroy, OnChanges {
   private _intlChanges: Subscription;
 
   /** A date representing the period (month or year) to start the calendar in. */
@@ -95,6 +100,12 @@ export class MatCalendar<D> implements AfterContentInit, OnDestroy {
   /** Emits when any date is selected. */
   @Output() userSelection = new EventEmitter<void>();
 
+  /** Reference to the current month view component. */
+  @ViewChild(MatMonthView) monthView: MatMonthView<D>;
+
+  /** Reference to the current year view component. */
+  @ViewChild(MatYearView) yearView: MatYearView<D>;
+
   /** Date filter for the month and year views. */
   _dateFilterForViews = (date: D) => {
     return !!date &&
@@ -166,6 +177,18 @@ export class MatCalendar<D> implements AfterContentInit, OnDestroy {
     this._intlChanges.unsubscribe();
   }
 
+  ngOnChanges(changes: SimpleChanges) {
+    const change = changes.minDate || changes.maxDate || changes.dateFilter;
+
+    if (change && !change.firstChange) {
+      const view = this.monthView || this.yearView;
+
+      if (view) {
+        view._init();
+      }
+    }
+  }
+
   /** Handles date selection in the month view. */
   _dateSelected(date: D): void {
     if (!this._dateAdapter.sameDate(date, this.selected)) {

src/lib/datepicker/month-view.ts

@@ -16,6 +16,7 @@ import {
   Optional,
   Output,
   ViewEncapsulation,
+  ChangeDetectorRef,
 } from '@angular/core';
 import {DateAdapter, MAT_DATE_FORMATS, MatDateFormats} from '@angular/material/core';
 import {MatCalendarCell} from './calendar-body';
@@ -93,7 +94,8 @@ export class MatMonthView<D> implements AfterContentInit {
   _weekdays: {long: string, narrow: string}[];
 
   constructor(@Optional() public _dateAdapter: DateAdapter<D>,
-              @Optional() @Inject(MAT_DATE_FORMATS) private _dateFormats: MatDateFormats) {
+              @Optional() @Inject(MAT_DATE_FORMATS) private _dateFormats: MatDateFormats,
+              private _changeDetectorRef: ChangeDetectorRef) {
     if (!this._dateAdapter) {
       throw createMissingDateImplError('DateAdapter');
     }
@@ -132,7 +134,7 @@ export class MatMonthView<D> implements AfterContentInit {
   }
 
   /** Initializes this month view. */
-  private _init() {
+  _init() {
     this._selectedDate = this._getDateInCurrentMonth(this.selected);
     this._todayDate = this._getDateInCurrentMonth(this._dateAdapter.today());
     this._monthLabel =
@@ -146,6 +148,7 @@ export class MatMonthView<D> implements AfterContentInit {
          this._dateAdapter.getFirstDayOfWeek()) % DAYS_PER_WEEK;
 
     this._createWeekCells();
+    this._changeDetectorRef.markForCheck();
   }
 
   /** Creates MatCalendarCells for the dates in this month. */

src/lib/datepicker/year-view.ts

@@ -16,6 +16,7 @@ import {
   Optional,
   Output,
   ViewEncapsulation,
+  ChangeDetectorRef,
 } from '@angular/core';
 import {DateAdapter, MAT_DATE_FORMATS, MatDateFormats} from '@angular/material/core';
 import {MatCalendarCell} from './calendar-body';
@@ -79,7 +80,8 @@ export class MatYearView<D> implements AfterContentInit {
   _selectedMonth: number | null;
 
   constructor(@Optional() public _dateAdapter: DateAdapter<D>,
-              @Optional() @Inject(MAT_DATE_FORMATS) private _dateFormats: MatDateFormats) {
+              @Optional() @Inject(MAT_DATE_FORMATS) private _dateFormats: MatDateFormats,
+              private _changeDetectorRef: ChangeDetectorRef) {
     if (!this._dateAdapter) {
       throw createMissingDateImplError('DateAdapter');
     }
@@ -104,7 +106,7 @@ export class MatYearView<D> implements AfterContentInit {
   }
 
   /** Initializes this month view. */
-  private _init() {
+  _init() {
     this._selectedMonth = this._getMonthInCurrentYear(this.selected);
     this._todayMonth = this._getMonthInCurrentYear(this._dateAdapter.today());
     this._yearLabel = this._dateAdapter.getYearName(this.activeDate);
@@ -113,6 +115,7 @@ export class MatYearView<D> implements AfterContentInit {
     // First row of months only contains 5 elements so we can fit the year label on the same row.
     this._months = [[0, 1, 2, 3], [4, 5, 6, 7], [8, 9, 10, 11]].map(row => row.map(
         month => this._createCellForMonth(month, monthNames[month])));
+    this._changeDetectorRef.markForCheck();
   }
 
   /**