From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Jake Potrebic <jake.m.potrebic@gmail.com>
Date: Sun, 22 Aug 2021 15:21:57 -0700
Subject: [PATCH] Fix entity type tags suggestions in selectors

This would really be better as a client fix because just to fix it
all EntityArguments have been told to ask the server for completions
when if this was fixed on the client, that wouldn't be needed.

Mojira Issue: https://bugs.mojang.com/browse/MC-235045

diff --git a/src/main/java/net/minecraft/commands/CommandSourceStack.java b/src/main/java/net/minecraft/commands/CommandSourceStack.java
index b14773074fc4b10ef427eb0ad9e21601a7287901..e0dd0fc1638377f4d4226d4b2976b901d635dff0 100644
--- a/src/main/java/net/minecraft/commands/CommandSourceStack.java
+++ b/src/main/java/net/minecraft/commands/CommandSourceStack.java
@@ -412,4 +412,20 @@ public class CommandSourceStack implements SharedSuggestionProvider, com.destroy
         return this.source.getBukkitSender(this);
     }
     // CraftBukkit end
+    // Paper start - override getSelectedEntities
+    @Override
+    public Collection<String> getSelectedEntities() {
+        if (io.papermc.paper.configuration.GlobalConfiguration.get().commands.fixTargetSelectorTagCompletion && this.source instanceof ServerPlayer player) {
+            double pickDistance = player.gameMode.getGameModeForPlayer().isCreative() ? 5.0F : 4.5F;
+            Vec3 min = player.getEyePosition(1.0F);
+            Vec3 viewVector = player.getViewVector(1.0F);
+            Vec3 max = min.add(viewVector.x * pickDistance, viewVector.y * pickDistance, viewVector.z * pickDistance);
+            net.minecraft.world.phys.AABB aabb = player.getBoundingBox().expandTowards(viewVector.scale(pickDistance)).inflate(1.0D, 1.0D, 1.0D);
+            pickDistance = player.gameMode.getGameModeForPlayer().isCreative() ? 6.0F : pickDistance;
+            net.minecraft.world.phys.EntityHitResult hitResult = net.minecraft.world.entity.projectile.ProjectileUtil.getEntityHitResult(player, min, max, aabb, (e) -> !e.isSpectator() && e.isPickable(), pickDistance);
+            return hitResult != null ? java.util.Collections.singletonList(hitResult.getEntity().getStringUUID()) : SharedSuggestionProvider.super.getSelectedEntities();
+        }
+        return SharedSuggestionProvider.super.getSelectedEntities();
+    }
+    // Paper end
 }
diff --git a/src/main/java/net/minecraft/commands/Commands.java b/src/main/java/net/minecraft/commands/Commands.java
index e70e5af7e49e4ccf332d9ce44e1a106344b35490..a0f5aa8c3cfce63af9cb286278a7fdebd7aa3642 100644
--- a/src/main/java/net/minecraft/commands/Commands.java
+++ b/src/main/java/net/minecraft/commands/Commands.java
@@ -422,6 +422,7 @@ public class Commands {
     private void fillUsableCommands(CommandNode<CommandSourceStack> tree, CommandNode<SharedSuggestionProvider> result, CommandSourceStack source, Map<CommandNode<CommandSourceStack>, CommandNode<SharedSuggestionProvider>> resultNodes) {
         Iterator iterator = tree.getChildren().iterator();
 
+        boolean registeredAskServerSuggestionsForTree = false; // Paper - tell clients to ask server for suggestions for EntityArguments
         while (iterator.hasNext()) {
             CommandNode<CommandSourceStack> commandnode2 = (CommandNode) iterator.next();
             if ( !org.spigotmc.SpigotConfig.sendNamespaced && commandnode2.getName().contains( ":" ) ) continue; // Spigot
@@ -443,6 +444,12 @@ public class Commands {
 
                     if (requiredargumentbuilder.getSuggestionsProvider() != null) {
                         requiredargumentbuilder.suggests(SuggestionProviders.safelySwap(requiredargumentbuilder.getSuggestionsProvider()));
+                        // Paper start - tell clients to ask server for suggestions for EntityArguments
+                        registeredAskServerSuggestionsForTree = requiredargumentbuilder.getSuggestionsProvider() == net.minecraft.commands.synchronization.SuggestionProviders.ASK_SERVER;
+                    } else if (io.papermc.paper.configuration.GlobalConfiguration.get().commands.fixTargetSelectorTagCompletion && !registeredAskServerSuggestionsForTree && requiredargumentbuilder.getType() instanceof net.minecraft.commands.arguments.EntityArgument) {
+                        requiredargumentbuilder.suggests(requiredargumentbuilder.getType()::listSuggestions);
+                        registeredAskServerSuggestionsForTree = true; // You can only
+                        // Paper end - tell clients to ask server for suggestions for EntityArguments
                     }
                 }
 
diff --git a/src/main/java/net/minecraft/commands/arguments/EntityArgument.java b/src/main/java/net/minecraft/commands/arguments/EntityArgument.java
index 850db283bf12345e9e7d7e8e590dbe8135c6dce1..a2ea64b7ec5f47224312a1e08dd64347be6f7c43 100644
--- a/src/main/java/net/minecraft/commands/arguments/EntityArgument.java
+++ b/src/main/java/net/minecraft/commands/arguments/EntityArgument.java
@@ -128,7 +128,7 @@ public class EntityArgument implements ArgumentType<EntitySelector> {
             StringReader stringreader = new StringReader(suggestionsbuilder.getInput());
 
             stringreader.setCursor(suggestionsbuilder.getStart());
-            EntitySelectorParser argumentparserselector = new EntitySelectorParser(stringreader, icompletionprovider.hasPermission(2));
+            EntitySelectorParser argumentparserselector = new EntitySelectorParser(stringreader, icompletionprovider.hasPermission(2), true); // Paper
 
             try {
                 argumentparserselector.parse();
diff --git a/src/main/java/net/minecraft/commands/arguments/selector/EntitySelectorParser.java b/src/main/java/net/minecraft/commands/arguments/selector/EntitySelectorParser.java
index ad99d67af92cda03beb1142b02082ee1bfc8a64a..a57ae219d57ed47baedfb73b3d815f39d4f87035 100644
--- a/src/main/java/net/minecraft/commands/arguments/selector/EntitySelectorParser.java
+++ b/src/main/java/net/minecraft/commands/arguments/selector/EntitySelectorParser.java
@@ -115,12 +115,19 @@ public class EntitySelectorParser {
     private boolean hasScores;
     private boolean hasAdvancements;
     private boolean usesSelectors;
+    public boolean parsingEntityArgumentSuggestions; // Paper - track when parsing EntityArgument suggestions
 
     public EntitySelectorParser(StringReader reader) {
         this(reader, true);
     }
 
     public EntitySelectorParser(StringReader reader, boolean atAllowed) {
+        // Paper start
+        this(reader, atAllowed, false);
+    }
+    public EntitySelectorParser(StringReader reader, boolean atAllowed, boolean parsingEntityArgumentSuggestions) {
+        this.parsingEntityArgumentSuggestions = parsingEntityArgumentSuggestions;
+        // Paper end
         this.distance = MinMaxBounds.Doubles.ANY;
         this.level = MinMaxBounds.Ints.ANY;
         this.rotX = WrappedMinMaxBounds.ANY;
diff --git a/src/main/java/net/minecraft/commands/arguments/selector/options/EntitySelectorOptions.java b/src/main/java/net/minecraft/commands/arguments/selector/options/EntitySelectorOptions.java
index c2b26a089c423e5df9a5cbfd1c70efbd1acb0e7a..f2376374c4c6efdfd5cfcea4d30c4b8b4dbbb0d5 100644
--- a/src/main/java/net/minecraft/commands/arguments/selector/options/EntitySelectorOptions.java
+++ b/src/main/java/net/minecraft/commands/arguments/selector/options/EntitySelectorOptions.java
@@ -67,6 +67,19 @@ public class EntitySelectorOptions {
     public static final DynamicCommandExceptionType ERROR_ENTITY_TYPE_INVALID = new DynamicCommandExceptionType((entity) -> {
         return Component.translatable("argument.entity.options.type.invalid", entity);
     });
+    // Paper start
+    public static final DynamicCommandExceptionType ERROR_ENTITY_TAG_INVALID = new DynamicCommandExceptionType((object) -> {
+        return io.papermc.paper.adventure.PaperAdventure
+            .asVanilla(net.kyori.adventure.text.Component
+                .text("Invalid or unknown entity type tag '" + object + "'")
+                .hoverEvent(net.kyori.adventure.text.event.HoverEvent
+                    .showText(net.kyori.adventure.text.Component
+                        .text("You can disable this error in 'paper.yml'")
+                    )
+                )
+            );
+    });
+    // Paper end
 
     private static void register(String id, EntitySelectorOptions.Modifier handler, Predicate<EntitySelectorParser> condition, Component description) {
         OPTIONS.put(id, new EntitySelectorOptions.Option(handler, condition, description));
@@ -314,6 +327,12 @@ public class EntitySelectorOptions {
 
                     if (reader.isTag()) {
                         TagKey<EntityType<?>> tagKey = TagKey.create(Registry.ENTITY_TYPE_REGISTRY, ResourceLocation.read(reader.getReader()));
+                        // Paper start - throw error if invalid entity tag (only on suggestions to keep cmd success behavior)
+                        if (reader.parsingEntityArgumentSuggestions && io.papermc.paper.configuration.GlobalConfiguration.get().commands.fixTargetSelectorTagCompletion && !Registry.ENTITY_TYPE.isKnownTagName(tagKey)) {
+                            reader.getReader().setCursor(i);
+                            throw ERROR_ENTITY_TAG_INVALID.createWithContext(reader.getReader(), tagKey);
+                        }
+                        // Paper end
                         reader.addPredicate((entity) -> {
                             return entity.getType().is(tagKey) != bl;
                         });
