fix(input): placeholder covering value when using OnPush (#5660)

src/demo-app/input/input-demo.html

@@ -382,6 +382,11 @@ <h4>Textarea</h4>
     <button md-raised-button color="primary" (click)="ctrlDisabled = !ctrlDisabled">
       DISABLE TD CTRL
     </button>
+    <div>
+      <md-input-container>
+          <input mdInput placeholder="delayed value" [formControl]="delayedFormControl">
+      </md-input-container>
+    </div>
   </md-card-content>
 </md-card>
 

src/demo-app/input/input-demo.ts

@@ -1,4 +1,4 @@
-import {Component} from '@angular/core';
+import { Component, ChangeDetectionStrategy } from '@angular/core';
 import {FormControl, Validators} from '@angular/forms';
 
 
@@ -8,6 +8,7 @@ const EMAIL_REGEX = /^[a-zA-Z0-9.!#$%&’*+/=?^_`{|}~-]+@[a-zA-Z0-9-]+(?:\.[a-zA
 
 @Component({
   moduleId: module.id,
+  changeDetection: ChangeDetectionStrategy.OnPush,
   selector: 'input-demo',
   templateUrl: 'input-demo.html',
   styleUrls: ['input-demo.css'],
@@ -38,8 +39,13 @@ export class InputDemo {
   rows = 8;
   formControl = new FormControl('hello', Validators.required);
   emailFormControl = new FormControl('', [Validators.required, Validators.pattern(EMAIL_REGEX)]);
+  delayedFormControl = new FormControl('');
   model = 'hello';
 
+  constructor() {
+    setTimeout(() => this.delayedFormControl.setValue('hello'), 100);
+  }
+
   addABunch(n: number) {
     for (let x = 0; x < n; x++) {
       this.items.push({ value: ++max });

src/lib/input/input-container.spec.ts

@@ -1,5 +1,5 @@
 import {async, ComponentFixture, inject, TestBed} from '@angular/core/testing';
-import {Component, ViewChild} from '@angular/core';
+import {Component, ViewChild, ChangeDetectionStrategy} from '@angular/core';
 import {
   FormControl,
   FormGroup,
@@ -61,6 +61,7 @@ describe('MdInputContainer without forms', function () {
         MdInputContainerWithValueBinding,
         MdTextareaWithBindings,
         MdInputContainerWithNgIf,
+        MdInputContainerOnPush,
       ],
     });
 
@@ -587,6 +588,22 @@ describe('MdInputContainer without forms', function () {
     expect(prefixEl.nativeElement.innerText.trim()).toEqual('Prefix');
     expect(suffixEl.nativeElement.innerText.trim()).toEqual('Suffix');
   });
+
+  it('should update empty class when value changes programmatically and OnPush', () => {
+    let fixture = TestBed.createComponent(MdInputContainerOnPush);
+    fixture.detectChanges();
+
+    let component = fixture.componentInstance;
+    let placeholder = fixture.debugElement
+        .query(By.css('.mat-input-placeholder')).nativeElement;
+
+    expect(placeholder.classList).toContain('mat-empty', 'Input initially empty');
+
+    component.formControl.setValue('something');
+    fixture.detectChanges();
+
+    expect(placeholder.classList).not.toContain('mat-empty', 'Input no longer empty');
+  });
 });
 
 describe('MdInputContainer with forms', () => {
@@ -1201,3 +1218,15 @@ class MdInputContainerWithPrefixAndSuffix {}
 class MdInputContainerWithNgIf {
   renderInput = true;
 }
+
+@Component({
+  changeDetection: ChangeDetectionStrategy.OnPush,
+  template: `
+    <md-input-container>
+      <input mdInput placeholder="Label" [formControl]="formControl">
+    </md-input-container>
+  `
+})
+class MdInputContainerOnPush {
+  formControl = new FormControl('');
+}

src/lib/input/input-container.ts

@@ -410,6 +410,12 @@ export class MdInputContainer implements AfterViewInit, AfterContentInit, AfterC
     // Re-validate when things change.
     this._hintChildren.changes.subscribe(() => this._processHints());
     this._mdInputChild._placeholderChange.subscribe(() => this._validatePlaceholders());
+
+    // Mark for check when the input's value changes to recalculate whether input is empty
+    const control = this._mdInputChild._ngControl;
+    if (control && control.valueChanges) {
+      control.valueChanges.subscribe(() => this._changeDetectorRef.markForCheck());
+    }
   }
 
   ngAfterContentChecked() {