Add cancellable ToastAddEvent (#8952)

src/main/java/net/minecraftforge/client/ForgeHooksClient.java

@@ -27,6 +27,7 @@ import net.minecraft.client.color.item.ItemColors;
 import net.minecraft.client.gui.Font;
 import net.minecraft.client.gui.GuiComponent;
 import net.minecraft.client.gui.components.LerpingBossEvent;
+import net.minecraft.client.gui.components.toasts.Toast;
 import net.minecraft.client.gui.screens.ConfirmScreen;
 import net.minecraft.client.gui.screens.Screen;
 import net.minecraft.client.gui.screens.TitleScreen;
@@ -128,6 +129,7 @@ import net.minecraftforge.client.event.RenderTooltipEvent;
 import net.minecraftforge.client.event.ScreenEvent;
 import net.minecraftforge.client.event.ScreenshotEvent;
 import net.minecraftforge.client.event.TextureStitchEvent;
+import net.minecraftforge.client.event.ToastAddEvent;
 import net.minecraftforge.client.event.ViewportEvent;
 import net.minecraftforge.client.event.sound.PlaySoundEvent;
 import net.minecraftforge.client.extensions.common.IClientFluidTypeExtensions;
@@ -1098,6 +1100,11 @@ public class ForgeHooksClient
         return event;
     }
 
+    public static boolean onToastAdd(Toast toast)
+    {
+        return MinecraftForge.EVENT_BUS.post(new ToastAddEvent(toast));
+    }
+
     public static boolean isBlockInSolidLayer(BlockState state)
     {
         var model = Minecraft.getInstance().getBlockRenderer().getBlockModel(state);

src/main/java/net/minecraftforge/client/event/ToastAddEvent.java

@@ -0,0 +1,38 @@
+/*
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
+ */
+
+package net.minecraftforge.client.event;
+
+import net.minecraft.client.gui.components.toasts.Toast;
+import net.minecraftforge.common.MinecraftForge;
+import net.minecraftforge.eventbus.api.Cancelable;
+import net.minecraftforge.eventbus.api.Event;
+import net.minecraftforge.fml.LogicalSide;
+
+/**
+ * Fired when the client queues a {@link Toast} message to be shown onscreen.
+ * Toasts are small popups that appear on the top right of the screen, for certain actions such as unlocking Advancements and Recipes.
+ *
+ * <p>This event is {@linkplain Cancelable cancellable}, and does not {@linkplain HasResult have a result}.
+ * Cancelling the event stops the toast from being queued, which means it never renders.</p>
+ *
+ * <p>This event is fired on the {@linkplain MinecraftForge#EVENT_BUS main Forge event bus},
+ * only on the {@linkplain LogicalSide#CLIENT logical client}.</p>
+ */
+@Cancelable
+public class ToastAddEvent extends Event
+{
+    private final Toast toast;
+
+    public ToastAddEvent(Toast toast)
+    {
+        this.toast = toast;
+    }
+
+    public Toast getToast()
+    {
+        return toast;
+    }
+}