From 3ea8cf5c31f4b619504b7bffd69606534e919057 Mon Sep 17 00:00:00 2001
From: Kristiyan Kostadinov <crisbeto@users.noreply.github.com>
Date: Mon, 9 Dec 2024 17:43:25 +0100
Subject: [PATCH] fix(material/paginator): ignore clicks on disabled buttons
 (#30138)

The changes in #29379 made the paginator interactive while they're disabled in order to improve accessibility, but as a result it also allows for the buttons to navigate while they're disabled.

These changes add internal checks to ensure that the buttons don't navigate while disabled. I've also cleaned up the logic a bit so we don't have four different places that deal with navigations.

Fixes #30124.

(cherry picked from commit 8d3bca5eb0cc304075c85aa56ecdd6785e7e2a2d)
---
 src/material/paginator/paginator.html        | 16 ++---
 src/material/paginator/paginator.spec.ts     | 72 ++++++++++++++++----
 src/material/paginator/paginator.ts          | 56 ++++++++-------
 tools/public_api_guard/material/paginator.md |  1 +
 4 files changed, 101 insertions(+), 44 deletions(-)

diff --git a/src/material/paginator/paginator.html b/src/material/paginator/paginator.html
index 208966624e56..10ae36fabfb2 100644
--- a/src/material/paginator/paginator.html
+++ b/src/material/paginator/paginator.html
@@ -44,11 +44,11 @@
       @if (showFirstLastButtons) {
         <button mat-icon-button type="button"
                 class="mat-mdc-paginator-navigation-first"
-                (click)="firstPage()"
+                (click)="_buttonClicked(0, _previousButtonsDisabled())"
                 [attr.aria-label]="_intl.firstPageLabel"
                 [matTooltip]="_intl.firstPageLabel"
                 [matTooltipDisabled]="_previousButtonsDisabled()"
-                [matTooltipPosition]="'above'"
+                matTooltipPosition="above"
                 [disabled]="_previousButtonsDisabled()"
                 disabledInteractive>
           <svg class="mat-mdc-paginator-icon"
@@ -61,11 +61,11 @@
       }
       <button mat-icon-button type="button"
               class="mat-mdc-paginator-navigation-previous"
-              (click)="previousPage()"
+              (click)="_buttonClicked(pageIndex - 1, _previousButtonsDisabled())"
               [attr.aria-label]="_intl.previousPageLabel"
               [matTooltip]="_intl.previousPageLabel"
               [matTooltipDisabled]="_previousButtonsDisabled()"
-              [matTooltipPosition]="'above'"
+              matTooltipPosition="above"
               [disabled]="_previousButtonsDisabled()"
               disabledInteractive>
         <svg class="mat-mdc-paginator-icon"
@@ -77,11 +77,11 @@
       </button>
       <button mat-icon-button type="button"
               class="mat-mdc-paginator-navigation-next"
-              (click)="nextPage()"
+              (click)="_buttonClicked(pageIndex + 1, _nextButtonsDisabled())"
               [attr.aria-label]="_intl.nextPageLabel"
               [matTooltip]="_intl.nextPageLabel"
               [matTooltipDisabled]="_nextButtonsDisabled()"
-              [matTooltipPosition]="'above'"
+              matTooltipPosition="above"
               [disabled]="_nextButtonsDisabled()"
               disabledInteractive>
         <svg class="mat-mdc-paginator-icon"
@@ -94,11 +94,11 @@
       @if (showFirstLastButtons) {
         <button mat-icon-button type="button"
                 class="mat-mdc-paginator-navigation-last"
-                (click)="lastPage()"
+                (click)="_buttonClicked(getNumberOfPages() - 1, _nextButtonsDisabled())"
                 [attr.aria-label]="_intl.lastPageLabel"
                 [matTooltip]="_intl.lastPageLabel"
                 [matTooltipDisabled]="_nextButtonsDisabled()"
-                [matTooltipPosition]="'above'"
+                matTooltipPosition="above"
                 [disabled]="_nextButtonsDisabled()"
                 disabledInteractive>
           <svg class="mat-mdc-paginator-icon"
diff --git a/src/material/paginator/paginator.spec.ts b/src/material/paginator/paginator.spec.ts
index a1543ea5e97a..54180cd4bc07 100644
--- a/src/material/paginator/paginator.spec.ts
+++ b/src/material/paginator/paginator.spec.ts
@@ -1,4 +1,3 @@
-import {dispatchMouseEvent} from '@angular/cdk/testing/private';
 import {ChangeDetectorRef, Component, Provider, Type, ViewChild, inject} from '@angular/core';
 import {ComponentFixture, TestBed, fakeAsync, tick} from '@angular/core/testing';
 import {ThemePalette} from '@angular/material/core';
@@ -135,7 +134,7 @@ describe('MatPaginator', () => {
       const paginator = component.paginator;
       expect(paginator.pageIndex).toBe(0);
 
-      dispatchMouseEvent(getNextButton(fixture), 'click');
+      getNextButton(fixture).click();
 
       expect(paginator.pageIndex).toBe(1);
       expect(component.pageEvent).toHaveBeenCalledWith(
@@ -154,7 +153,7 @@ describe('MatPaginator', () => {
       fixture.detectChanges();
       expect(paginator.pageIndex).toBe(1);
 
-      dispatchMouseEvent(getPreviousButton(fixture), 'click');
+      getPreviousButton(fixture).click();
 
       expect(paginator.pageIndex).toBe(0);
       expect(component.pageEvent).toHaveBeenCalledWith(
@@ -164,12 +163,37 @@ describe('MatPaginator', () => {
         }),
       );
     });
+
+    it('should not navigate to the next page when the paginator is disabled', () => {
+      const fixture = createComponent(MatPaginatorApp);
+      expect(fixture.componentInstance.paginator.pageIndex).toBe(0);
+
+      fixture.componentInstance.disabled = true;
+      fixture.changeDetectorRef.markForCheck();
+      fixture.detectChanges();
+      getNextButton(fixture).click();
+      expect(fixture.componentInstance.paginator.pageIndex).toBe(0);
+    });
+
+    it('should not navigate to the previous page when the paginator is disabled', () => {
+      const fixture = createComponent(MatPaginatorApp);
+      fixture.componentInstance.pageIndex = 1;
+      fixture.changeDetectorRef.markForCheck();
+      fixture.detectChanges();
+
+      expect(fixture.componentInstance.paginator.pageIndex).toBe(1);
+
+      fixture.componentInstance.disabled = true;
+      fixture.changeDetectorRef.markForCheck();
+      fixture.detectChanges();
+      getPreviousButton(fixture).click();
+      expect(fixture.componentInstance.paginator.pageIndex).toBe(1);
+    });
   });
 
   it('should be able to show the first/last buttons', () => {
     const fixture = createComponent(MatPaginatorApp);
     expect(getFirstButton(fixture)).withContext('Expected first button to not exist.').toBeNull();
-
     expect(getLastButton(fixture)).withContext('Expected last button to not exist.').toBeNull();
 
     fixture.componentInstance.showFirstLastButtons = true;
@@ -271,7 +295,7 @@ describe('MatPaginator', () => {
     it('should be able to go to the last page via the last page button', () => {
       expect(paginator.pageIndex).toBe(0);
 
-      dispatchMouseEvent(getLastButton(fixture), 'click');
+      getLastButton(fixture).click();
 
       expect(paginator.pageIndex).toBe(9);
       expect(component.pageEvent).toHaveBeenCalledWith(
@@ -287,7 +311,7 @@ describe('MatPaginator', () => {
       fixture.detectChanges();
       expect(paginator.pageIndex).toBe(3);
 
-      dispatchMouseEvent(getFirstButton(fixture), 'click');
+      getFirstButton(fixture).click();
 
       expect(paginator.pageIndex).toBe(0);
       expect(component.pageEvent).toHaveBeenCalledWith(
@@ -305,7 +329,7 @@ describe('MatPaginator', () => {
       expect(paginator.hasNextPage()).toBe(false);
 
       component.pageEvent.calls.reset();
-      dispatchMouseEvent(getNextButton(fixture), 'click');
+      getNextButton(fixture).click();
 
       expect(component.pageEvent).not.toHaveBeenCalled();
       expect(paginator.pageIndex).toBe(9);
@@ -316,11 +340,35 @@ describe('MatPaginator', () => {
       expect(paginator.hasPreviousPage()).toBe(false);
 
       component.pageEvent.calls.reset();
-      dispatchMouseEvent(getPreviousButton(fixture), 'click');
+      getPreviousButton(fixture).click();
 
       expect(component.pageEvent).not.toHaveBeenCalled();
       expect(paginator.pageIndex).toBe(0);
     });
+
+    it('should not navigate to the last page when the paginator is disabled', () => {
+      expect(fixture.componentInstance.paginator.pageIndex).toBe(0);
+
+      fixture.componentInstance.disabled = true;
+      fixture.changeDetectorRef.markForCheck();
+      fixture.detectChanges();
+      getLastButton(fixture).click();
+      expect(fixture.componentInstance.paginator.pageIndex).toBe(0);
+    });
+
+    it('should not navigate to the first page when the paginator is disabled', () => {
+      fixture.componentInstance.pageIndex = 1;
+      fixture.changeDetectorRef.markForCheck();
+      fixture.detectChanges();
+
+      expect(fixture.componentInstance.paginator.pageIndex).toBe(1);
+
+      fixture.componentInstance.disabled = true;
+      fixture.changeDetectorRef.markForCheck();
+      fixture.detectChanges();
+      getFirstButton(fixture).click();
+      expect(fixture.componentInstance.paginator.pageIndex).toBe(1);
+    });
   });
 
   it('should mark for check when inputs are changed directly', () => {
@@ -569,19 +617,19 @@ describe('MatPaginator', () => {
   });
 });
 
-function getPreviousButton(fixture: ComponentFixture<any>) {
+function getPreviousButton(fixture: ComponentFixture<any>): HTMLButtonElement {
   return fixture.nativeElement.querySelector('.mat-mdc-paginator-navigation-previous');
 }
 
-function getNextButton(fixture: ComponentFixture<any>) {
+function getNextButton(fixture: ComponentFixture<any>): HTMLButtonElement {
   return fixture.nativeElement.querySelector('.mat-mdc-paginator-navigation-next');
 }
 
-function getFirstButton(fixture: ComponentFixture<any>) {
+function getFirstButton(fixture: ComponentFixture<any>): HTMLButtonElement {
   return fixture.nativeElement.querySelector('.mat-mdc-paginator-navigation-first');
 }
 
-function getLastButton(fixture: ComponentFixture<any>) {
+function getLastButton(fixture: ComponentFixture<any>): HTMLButtonElement {
   return fixture.nativeElement.querySelector('.mat-mdc-paginator-navigation-last');
 }
 
diff --git a/src/material/paginator/paginator.ts b/src/material/paginator/paginator.ts
index 80efe631b232..f774e7882f86 100644
--- a/src/material/paginator/paginator.ts
+++ b/src/material/paginator/paginator.ts
@@ -241,48 +241,32 @@ export class MatPaginator implements OnInit, OnDestroy {
 
   /** Advances to the next page if it exists. */
   nextPage(): void {
-    if (!this.hasNextPage()) {
-      return;
+    if (this.hasNextPage()) {
+      this._navigate(this.pageIndex + 1);
     }
-
-    const previousPageIndex = this.pageIndex;
-    this.pageIndex = this.pageIndex + 1;
-    this._emitPageEvent(previousPageIndex);
   }
 
   /** Move back to the previous page if it exists. */
   previousPage(): void {
-    if (!this.hasPreviousPage()) {
-      return;
+    if (this.hasPreviousPage()) {
+      this._navigate(this.pageIndex - 1);
     }
-
-    const previousPageIndex = this.pageIndex;
-    this.pageIndex = this.pageIndex - 1;
-    this._emitPageEvent(previousPageIndex);
   }
 
   /** Move to the first page if not already there. */
   firstPage(): void {
     // hasPreviousPage being false implies at the start
-    if (!this.hasPreviousPage()) {
-      return;
+    if (this.hasPreviousPage()) {
+      this._navigate(0);
     }
-
-    const previousPageIndex = this.pageIndex;
-    this.pageIndex = 0;
-    this._emitPageEvent(previousPageIndex);
   }
 
   /** Move to the last page if not already there. */
   lastPage(): void {
     // hasNextPage being false implies at the end
-    if (!this.hasNextPage()) {
-      return;
+    if (this.hasNextPage()) {
+      this._navigate(this.getNumberOfPages() - 1);
     }
-
-    const previousPageIndex = this.pageIndex;
-    this.pageIndex = this.getNumberOfPages() - 1;
-    this._emitPageEvent(previousPageIndex);
   }
 
   /** Whether there is a previous page. */
@@ -369,4 +353,28 @@ export class MatPaginator implements OnInit, OnDestroy {
       length: this.length,
     });
   }
+
+  /** Navigates to a specific page index. */
+  private _navigate(index: number) {
+    const previousIndex = this.pageIndex;
+
+    if (index !== previousIndex) {
+      this.pageIndex = index;
+      this._emitPageEvent(previousIndex);
+    }
+  }
+
+  /**
+   * Callback invoked when one of the navigation buttons is called.
+   * @param targetIndex Index to which the paginator should navigate.
+   * @param isDisabled Whether the button is disabled.
+   */
+  protected _buttonClicked(targetIndex: number, isDisabled: boolean) {
+    // Note that normally disabled buttons won't dispatch the click event, but the paginator ones
+    // do, because we're using `disabledInteractive` to allow them to be focusable. We need to
+    // check here to avoid the navigation.
+    if (!isDisabled) {
+      this._navigate(targetIndex);
+    }
+  }
 }
diff --git a/tools/public_api_guard/material/paginator.md b/tools/public_api_guard/material/paginator.md
index 7fb1f2751433..26cc3875d2bb 100644
--- a/tools/public_api_guard/material/paginator.md
+++ b/tools/public_api_guard/material/paginator.md
@@ -35,6 +35,7 @@ export function MAT_PAGINATOR_INTL_PROVIDER_FACTORY(parentIntl: MatPaginatorIntl
 // @public
 export class MatPaginator implements OnInit, OnDestroy {
     constructor(_intl: MatPaginatorIntl, _changeDetectorRef: ChangeDetectorRef, defaults?: MatPaginatorDefaultOptions);
+    protected _buttonClicked(targetIndex: number, isDisabled: boolean): void;
     _changePageSize(pageSize: number): void;
     color: ThemePalette;
     disabled: boolean;