Optimize Dynamic#get Missing Keys

get was calling toString() on every NBT object that was ever asked for an optional
key from the object to build a string for the error text.

When done on large NBT objects, this was using a ton of computation time building the
JSON representation of the NBT object.

Now we will just skip the value when 99.9999% of the time the text is never even printed.

Spigot-Server-Patches/0619-Optimize-Dynamic-get-Missing-Keys.patch

@@ -0,0 +1,34 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Aikar <aikar@aikar.co>
+Date: Mon, 21 Dec 2020 11:01:42 -0500
+Subject: [PATCH] Optimize Dynamic#get Missing Keys
+
+get was calling toString() on every NBT object that was ever asked for an optional
+key from the object to build a string for the error text.
+
+When done on large NBT objects, this was using a ton of computation time building the
+JSON representation of the NBT object.
+
+Now we will just skip the value when 99.9999% of the time the text is never even printed.
+
+diff --git a/src/main/java/com/mojang/serialization/Dynamic.java b/src/main/java/com/mojang/serialization/Dynamic.java
+index a75d3db046dc985a03b4b870c91f41de1bd66bad..044facc9de9e8e582d7953d681c0c051578979c3 100644
+--- a/src/main/java/com/mojang/serialization/Dynamic.java
++++ b/src/main/java/com/mojang/serialization/Dynamic.java
+@@ -17,6 +17,7 @@ import java.util.stream.Stream;
+ 
+ @SuppressWarnings("unused")
+ public class Dynamic<T> extends DynamicLike<T> {
++    private static final boolean DEBUG_MISSING_KEYS = Boolean.getBoolean("Paper.debugDynamicMissingKeys"); // Paper
+     private final T value;
+ 
+     public Dynamic(final DynamicOps<T> ops) {
+@@ -113,7 +114,7 @@ public class Dynamic<T> extends DynamicLike<T> {
+         return new OptionalDynamic<>(ops, ops.getMap(value).flatMap(m -> {
+             final T value = m.get(key);
+             if (value == null) {
+-                return DataResult.error("key missing: " + key + " in " + this.value);
++                return DataResult.error(DEBUG_MISSING_KEYS ? "key missing: " + key + " in " + this.value : "key missing: " + key); // Paper
+             }
+             return DataResult.success(new Dynamic<>(ops, value));
+         }));

scripts/importmcdev.sh

@@ -108,6 +108,7 @@ importLibrary com.mojang authlib com/mojang/authlib yggdrasil/YggdrasilGameProfi
 importLibrary com.mojang datafixerupper com/mojang/datafixers DataFixerBuilder.java
 importLibrary com.mojang datafixerupper com/mojang/datafixers/util Either.java
 importLibrary com.mojang datafixerupper com/mojang/serialization/codecs KeyDispatchCodec.java
+importLibrary com.mojang datafixerupper com/mojang/serialization Dynamic.java
 
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