Do not bypass Ingredient.TagValue#getItems during server resource reload

This breaks KubeJS/CraftTweaker's workarounds for tags not being
available during RecipeManager#apply (even though they become available
right after)

Related: #555

Author: embeddedt

forge/src/main/java/org/embeddedt/modernfix/forge/load/MinecraftServerReloadTracker.java

@@ -0,0 +1,9 @@
+package org.embeddedt.modernfix.forge.load;
+
+public class MinecraftServerReloadTracker {
+    public static int ACTIVE_RELOADS = 0;
+
+    public static boolean isReloadActive() {
+        return ACTIVE_RELOADS > 0;
+    }
+}

forge/src/main/java/org/embeddedt/modernfix/forge/mixin/core/MinecraftServerMixin.java

@@ -0,0 +1,28 @@
+package org.embeddedt.modernfix.forge.mixin.core;
+
+import com.llamalad7.mixinextras.injector.ModifyExpressionValue;
+import net.minecraft.server.MinecraftServer;
+import org.embeddedt.modernfix.forge.load.MinecraftServerReloadTracker;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.injection.At;
+import org.spongepowered.asm.mixin.injection.Inject;
+import org.spongepowered.asm.mixin.injection.callback.CallbackInfoReturnable;
+
+import java.util.Collection;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.Executor;
+
+@Mixin(MinecraftServer.class)
+public class MinecraftServerMixin {
+    @Inject(method = "reloadResources", at = @At("HEAD"))
+    private void startReloadTrack(Collection<String> selectedIds, CallbackInfoReturnable<CompletableFuture<Void>> cir) {
+        MinecraftServerReloadTracker.ACTIVE_RELOADS++;
+    }
+
+    @ModifyExpressionValue(method = "reloadResources", at = @At(value = "INVOKE", target = "Ljava/util/concurrent/CompletableFuture;thenAcceptAsync(Ljava/util/function/Consumer;Ljava/util/concurrent/Executor;)Ljava/util/concurrent/CompletableFuture;", ordinal = 0))
+    private CompletableFuture<Void> mfix$endReloadTrack(CompletableFuture<Void> original) {
+        return original.thenAcceptAsync(val -> {
+            MinecraftServerReloadTracker.ACTIVE_RELOADS--;
+        }, (Executor)this);
+    }
+}

forge/src/main/java/org/embeddedt/modernfix/forge/mixin/core/WorldLoaderMixin.java

@@ -0,0 +1,29 @@
+package org.embeddedt.modernfix.forge.mixin.core;
+
+import com.llamalad7.mixinextras.injector.ModifyReturnValue;
+import com.llamalad7.mixinextras.sugar.Local;
+import net.minecraft.server.WorldLoader;
+import org.embeddedt.modernfix.forge.load.MinecraftServerReloadTracker;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.injection.At;
+import org.spongepowered.asm.mixin.injection.Inject;
+import org.spongepowered.asm.mixin.injection.callback.CallbackInfoReturnable;
+
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.Executor;
+
+@Mixin(WorldLoader.class)
+public class WorldLoaderMixin {
+    @Inject(method = "load", at = @At("HEAD"))
+    private static void trackStartReload(CallbackInfoReturnable<CompletableFuture<?>> cir) {
+        MinecraftServerReloadTracker.ACTIVE_RELOADS++;
+    }
+
+    @ModifyReturnValue(method = "load", at = @At("RETURN"))
+    private static <V> CompletableFuture<V> trackEndReload(CompletableFuture<V> original, @Local(ordinal = 1, argsOnly = true) Executor syncExecutor) {
+        return original.thenApplyAsync(val -> {
+            MinecraftServerReloadTracker.ACTIVE_RELOADS--;
+            return val;
+        }, syncExecutor);
+    }
+}

forge/src/main/java/org/embeddedt/modernfix/forge/mixin/perf/faster_ingredients/IngredientMixin.java

@@ -6,6 +6,7 @@
 import net.minecraft.core.registries.BuiltInRegistries;
 import net.minecraft.world.item.ItemStack;
 import net.minecraft.world.item.crafting.Ingredient;
+import org.embeddedt.modernfix.forge.load.MinecraftServerReloadTracker;
 import org.embeddedt.modernfix.forge.recipe.ExtendedIngredient;
 import org.embeddedt.modernfix.forge.recipe.IngredientItemStacksSoftReference;
 import org.jetbrains.annotations.Nullable;
@@ -34,13 +35,32 @@ public abstract class IngredientMixin implements ExtendedIngredient {
 
     private volatile IngredientItemStacksSoftReference mfix$cachedItemStacks;
 
+    /**
+     * Minecraft's server resource loading process has a design flaw in that tags are loaded, recipes are loaded,
+     * then tags are bound to the server registries. This results in recipe modification mods like KubeJS/CraftTweaker
+     * not being able to use Ingredient.test reliably as the TagValue will not find any contents for the given tag.
+     * To work around this issue these mods track tag context themselves and then patch TagValue.getItems to use it
+     * during the resource reload process. We often bypass Value.getItems, so we must disable that bypass
+     * whenever a server reload is in progress.
+     * <p>
+     * An alternative fix would be to bind tags ourselves when the recipe manager reload begins, before control is
+     * handed to these mods. However, it's unclear if there would be any negative side effects from binding tags early
+     * like this. Moreover, this fix would only work if the mod-provided patches to getItems read exactly what the
+     * registry would normally contain, rather than a modified version.
+     * <p>
+     * Note: this is a separate problem from the issue where clients may receive recipes before tags in 1.21.
+     */
+    private boolean mfix$areTagsAvailable() {
+        return !MinecraftServerReloadTracker.isReloadActive();
+    }
+
     /**
      * @author embeddedt
      * @reason tag ingredients can be tested without iterating over all items
      */
     @Inject(method = "test(Lnet/minecraft/world/item/ItemStack;)Z", at = @At(value = "INVOKE", target = "Lnet/minecraft/world/item/crafting/Ingredient;getItems()[Lnet/minecraft/world/item/ItemStack;"), cancellable = true)
     private void modernfix$fasterTagIngredientTest(ItemStack stack, CallbackInfoReturnable<Boolean> cir) {
-        if (this.isVanilla() && this.values.length == 1 && this.values[0] instanceof Ingredient.TagValue tagValue) {
+        if (this.isVanilla() && this.values.length == 1 && this.values[0] instanceof Ingredient.TagValue tagValue && mfix$areTagsAvailable()) {
             cir.setReturnValue(stack.getItemHolder().is(tagValue.tag));
         }
     }
@@ -60,7 +80,7 @@ private boolean containsItems() {
         for (Ingredient.Value value : this.values) {
             if (value instanceof Ingredient.ItemValue) {
                 return true;
-            } else if (value instanceof Ingredient.TagValue tagValue) {
+            } else if (value instanceof Ingredient.TagValue tagValue && mfix$areTagsAvailable()) {
                 var holderSetOpt = BuiltInRegistries.ITEM.getTag(tagValue.tag);
                 if (holderSetOpt.isPresent() && holderSetOpt.get().size() > 0) {
                     return true;
@@ -84,7 +104,7 @@ private boolean containsItems() {
      */
     @Inject(method = "getStackingIds", at = @At(value = "INVOKE", target = "Lnet/minecraft/world/item/crafting/Ingredient;getItems()[Lnet/minecraft/world/item/ItemStack;"), cancellable = true)
     private void modernfix$fasterTagIngredientStacking(CallbackInfoReturnable<IntList> cir) {
-        if (this.isVanilla() && this.values.length == 1 && this.values[0] instanceof Ingredient.TagValue tagValue) {
+        if (this.isVanilla() && this.values.length == 1 && this.values[0] instanceof Ingredient.TagValue tagValue && mfix$areTagsAvailable()) {
             var tag = BuiltInRegistries.ITEM.getTag(tagValue.tag);
             if (!tag.isPresent() || tag.get().size() == 0) {
                 return;
@@ -124,7 +144,7 @@ private ItemStack[] computeItemsArray() {
         if (this.values.length == 1) {
             if (this.values[0] instanceof Ingredient.ItemValue itemValue) {
                 return new ItemStack[] { itemValue.item };
-            } else if (this.values[0] instanceof Ingredient.TagValue tagValue) {
+            } else if (this.values[0] instanceof Ingredient.TagValue tagValue && mfix$areTagsAvailable()) {
                 var tag = BuiltInRegistries.ITEM.getTag(tagValue.tag);
                 if (tag.isPresent() && tag.get().size() > 0) {
                     var holderSet = tag.get();