fix(material/menu): remove dependency on animations module

Second attempt at reworking the menu so it no longer depends on the animations module (after angular#30099). This should allow us to avoid some of the pitfalls of the animations module like occasional memory leaks (e.g. #47748) and reduce the bundle size.

src/material/menu/menu-animations.ts

@@ -20,6 +20,8 @@ import {
  * Animation duration and timing values are based on:
  * https://material.io/guidelines/components/menus.html#menus-usage
  * @docs-private
+ * @deprecated No longer used, will be removed.
+ * @breaking-change 21.0.0
  */
 export const matMenuAnimations: {
   readonly transformMenu: AnimationTriggerMetadata;

src/material/menu/menu-trigger.ts

@@ -40,7 +40,7 @@ import {
 } from '@angular/core';
 import {normalizePassiveListenerOptions} from '@angular/cdk/platform';
 import {merge, Observable, of as observableOf, Subscription} from 'rxjs';
-import {filter, takeUntil} from 'rxjs/operators';
+import {filter, take, takeUntil} from 'rxjs/operators';
 import {MatMenu, MenuCloseReason} from './menu';
 import {throwMatMenuRecursiveError} from './menu-errors';
 import {MatMenuItem} from './menu-item';
@@ -115,6 +115,7 @@ export class MatMenuTrigger implements AfterContentInit, OnDestroy {
   private _closingActionsSubscription = Subscription.EMPTY;
   private _hoverSubscription = Subscription.EMPTY;
   private _menuCloseSubscription = Subscription.EMPTY;
+  private _pendingRemoval: Subscription | undefined;
 
   /**
    * We're specifically looking for a `MatMenu` here since the generic `MatMenuPanel`
@@ -247,6 +248,7 @@ export class MatMenuTrigger implements AfterContentInit, OnDestroy {
       passiveEventListenerOptions,
     );
 
+    this._pendingRemoval?.unsubscribe();
     this._menuCloseSubscription.unsubscribe();
     this._closingActionsSubscription.unsubscribe();
     this._hoverSubscription.unsubscribe();
@@ -285,24 +287,39 @@ export class MatMenuTrigger implements AfterContentInit, OnDestroy {
       return;
     }
 
+    this._pendingRemoval?.unsubscribe();
+    const previousTrigger = PANELS_TO_TRIGGERS.get(menu);
+    PANELS_TO_TRIGGERS.set(menu, this);
+
+    // If the same menu is currently attached to another trigger,
+    // we need to close it so it doesn't end up in a broken state.
+    if (previousTrigger && previousTrigger !== this) {
+      previousTrigger.closeMenu();
+    }
+
     const overlayRef = this._createOverlay(menu);
     const overlayConfig = overlayRef.getConfig();
     const positionStrategy = overlayConfig.positionStrategy as FlexibleConnectedPositionStrategy;
 
     this._setPosition(menu, positionStrategy);
     overlayConfig.hasBackdrop =
       menu.hasBackdrop == null ? !this.triggersSubmenu() : menu.hasBackdrop;
-    overlayRef.attach(this._getPortal(menu));
 
-    if (menu.lazyContent) {
-      menu.lazyContent.attach(this.menuData);
+    // We need the `hasAttached` check for the case where the user kicked off a removal animation,
+    // but re-entered the menu. Re-attaching the same portal will trigger an error otherwise.
+    if (!overlayRef.hasAttached()) {
+      overlayRef.attach(this._getPortal(menu));
+      menu.lazyContent?.attach(this.menuData);
     }
 
     this._closingActionsSubscription = this._menuClosingActions().subscribe(() => this.closeMenu());
-    this._initMenu(menu);
+    menu.parentMenu = this.triggersSubmenu() ? this._parentMaterialMenu : undefined;
+    menu.direction = this.dir;
+    menu.focusFirstItem(this._openedBy || 'program');
+    this._setIsMenuOpen(true);
 
     if (menu instanceof MatMenu) {
-      menu._startAnimation();
+      menu._setIsOpen(true);
       menu._directDescendantItems.changes.pipe(takeUntil(menu.close)).subscribe(() => {
         // Re-adjust the position without locking when the amount of items
         // changes so that the overlay is allowed to pick a new optimal position.
@@ -338,12 +355,28 @@ export class MatMenuTrigger implements AfterContentInit, OnDestroy {
 
   /** Closes the menu and does the necessary cleanup. */
   private _destroyMenu(reason: MenuCloseReason) {
-    if (!this._overlayRef || !this.menuOpen) {
+    const overlayRef = this._overlayRef;
+    const menu = this._menu;
+
+    if (!overlayRef || !this.menuOpen) {
       return;
     }
 
     this._closingActionsSubscription.unsubscribe();
-    this._overlayRef.detach();
+    this._pendingRemoval?.unsubscribe();
+
+    // Note that we don't wait for the animation to finish if another trigger took
+    // over the menu, because the panel will end up empty which looks glitchy.
+    if (menu instanceof MatMenu && this._ownsMenu(menu)) {
+      this._pendingRemoval = menu._animationDone.pipe(take(1)).subscribe(() => overlayRef.detach());
+      menu._setIsOpen(false);
+    } else {
+      overlayRef.detach();
+    }
+
+    if (menu && this._ownsMenu(menu)) {
+      PANELS_TO_TRIGGERS.delete(menu);
+    }
 
     // Always restore focus if the user is navigating using the keyboard or the menu was opened
     // programmatically. We don't restore for non-root triggers, because it can prevent focus
@@ -355,30 +388,6 @@ export class MatMenuTrigger implements AfterContentInit, OnDestroy {
 
     this._openedBy = undefined;
     this._setIsMenuOpen(false);
-
-    if (this.menu && this._ownsMenu(this.menu)) {
-      PANELS_TO_TRIGGERS.delete(this.menu);
-    }
-  }
-
-  /**
-   * This method sets the menu state to open and focuses the first item if
-   * the menu was opened via the keyboard.
-   */
-  private _initMenu(menu: MatMenuPanel): void {
-    const previousTrigger = PANELS_TO_TRIGGERS.get(menu);
-
-    // If the same menu is currently attached to another trigger,
-    // we need to close it so it doesn't end up in a broken state.
-    if (previousTrigger && previousTrigger !== this) {
-      previousTrigger.closeMenu();
-    }
-
-    PANELS_TO_TRIGGERS.set(menu, this);
-    menu.parentMenu = this.triggersSubmenu() ? this._parentMaterialMenu : undefined;
-    menu.direction = this.dir;
-    menu.focusFirstItem(this._openedBy || 'program');
-    this._setIsMenuOpen(true);
   }
 
   // set state rather than toggle to support triggers sharing a menu

src/material/menu/menu.html

@@ -3,12 +3,15 @@
     class="mat-mdc-menu-panel"
     [id]="panelId"
     [class]="_classList"
+    [class.mat-menu-panel-animations-disabled]="_animationsDisabled"
+    [class.mat-menu-panel-exit-animation]="_panelAnimationState === 'void'"
+    [class.mat-menu-panel-animating]="_isAnimating"
     (click)="closed.emit('click')"
-    [@transformMenu]="_panelAnimationState"
-    (@transformMenu.start)="_onAnimationStart($event)"
-    (@transformMenu.done)="_onAnimationDone($event)"
     tabindex="-1"
     role="menu"
+    (animationstart)="_onAnimationStart($event.animationName)"
+    (animationend)="_onAnimationDone($event.animationName)"
+    (animationcancel)="_onAnimationDone($event.animationName)"
     [attr.aria-label]="ariaLabel || null"
     [attr.aria-labelledby]="ariaLabelledby || null"
     [attr.aria-describedby]="ariaDescribedby || null">

src/material/menu/menu.scss

@@ -31,10 +31,33 @@ mat-menu {
   }
 }
 
+@keyframes _mat-menu-enter {
+  from {
+    opacity: 0;
+    transform: scale(0.8);
+  }
+
+  to {
+    opacity: 1;
+    transform: none;
+  }
+}
+
+@keyframes _mat-menu-exit {
+  from {
+    opacity: 1;
+  }
+
+  to {
+    opacity: 0;
+  }
+}
+
 .mat-mdc-menu-panel {
   @include menu-common.base;
   box-sizing: border-box;
   outline: 0;
+  animation: _mat-menu-enter 120ms cubic-bezier(0, 0, 0.2, 1);
 
   @include token-utils.use-tokens(tokens-mat-menu.$prefix, tokens-mat-menu.get-token-slots()) {
     @include token-utils.create-token-slot(border-radius, container-shape);
@@ -48,14 +71,22 @@ mat-menu {
   // We should clean it up eventually and re-approve all the screenshots.
   will-change: transform, opacity;
 
+  &.mat-menu-panel-exit-animation {
+    animation: _mat-menu-exit 100ms 25ms linear forwards;
+  }
+
+  &.mat-menu-panel-animations-disabled {
+    animation: none;
+  }
+
   // Prevent users from interacting with the panel while it's animating. Note that
   // people won't be able to click through it, because the overlay pane will catch the click.
   // This fixes the following issues:
   //  * Users accidentally opening sub-menus when the `overlapTrigger` option is enabled.
   //  * Users accidentally tapping on content inside the sub-menu on touch devices, if the
   //    sub-menu overlaps the trigger. The issue is due to touch devices emulating the
   //    `mouseenter` event by dispatching it on tap.
-  &.ng-animating {
+  &.mat-menu-panel-animating {
     pointer-events: none;
 
     // If the same menu is assigned to multiple triggers and the user moves quickly between them