From c885ca1d7c027919bb62a716a91e5687f998de67 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Noel=20N=C3=A9meth?= <noel@noelnemeth.com>
Date: Sun, 17 Jul 2022 20:28:14 +0200
Subject: [PATCH] Fix index out of bounds when creating a command packet
 (#1243)

---
 .../minestom/server/command/GraphConverter.java  | 16 ++++++++--------
 .../server/command/CommandPacketTest.java        | 14 ++++++++++++++
 2 files changed, 22 insertions(+), 8 deletions(-)

diff --git a/src/main/java/net/minestom/server/command/GraphConverter.java b/src/main/java/net/minestom/server/command/GraphConverter.java
index f01dcee34..a9424257a 100644
--- a/src/main/java/net/minestom/server/command/GraphConverter.java
+++ b/src/main/java/net/minestom/server/command/GraphConverter.java
@@ -42,14 +42,14 @@ final class GraphConverter {
 
         final DeclareCommandsPacket.Node node = new DeclareCommandsPacket.Node();
         int[] packetNodeChildren = new int[children.size()];
-        for (int i = 0; i < packetNodeChildren.length; i++) {
+        for (int i = 0, appendIndex = 0; i < children.size(); i++) {
             final int[] append = append(children.get(i), to, rootRedirect, id, redirect, redirectSetters, player);
             if (append.length == 1) {
-                packetNodeChildren[i] = append[0];
+                packetNodeChildren[appendIndex++] = append[0];
             } else {
                 packetNodeChildren = Arrays.copyOf(packetNodeChildren, packetNodeChildren.length + append.length - 1);
-                System.arraycopy(append, 0, packetNodeChildren, i, append.length);
-                i += append.length;
+                System.arraycopy(append, 0, packetNodeChildren, appendIndex, append.length);
+                appendIndex += append.length;
             }
         }
         node.children = packetNodeChildren;
@@ -125,15 +125,15 @@ final class GraphConverter {
                 List<Runnable> setters = new ArrayList<>();
                 int[] res = new int[special.arguments().size()];
                 List<?> arguments = special.arguments();
-                for (int i = 0; i < arguments.size(); i++) {
+                for (int i = 0, appendIndex = 0; i < arguments.size(); i++) {
                     Object arg = arguments.get(i);
                     final int[] append = append(new GraphImpl.NodeImpl((Argument<?>) arg, null, List.of()), to, rootRedirect, id, r, setters, player);
                     if (append.length == 1) {
-                        res[i] = append[0];
+                        res[appendIndex++] = append[0];
                     } else {
                         res = Arrays.copyOf(res, res.length + append.length - 1);
-                        System.arraycopy(append, 0, res, i, append.length);
-                        i += append.length;
+                        System.arraycopy(append, 0, res, appendIndex, append.length);
+                        appendIndex += append.length;
                     }
                 }
                 r.set(id.get());
diff --git a/src/test/java/net/minestom/server/command/CommandPacketTest.java b/src/test/java/net/minestom/server/command/CommandPacketTest.java
index f064de7e5..18fdb74ba 100644
--- a/src/test/java/net/minestom/server/command/CommandPacketTest.java
+++ b/src/test/java/net/minestom/server/command/CommandPacketTest.java
@@ -154,6 +154,20 @@ public class CommandPacketTest {
                 int3->int4
                 """, graph);
     }
+    @Test
+    public void twoEnumAndOneLiteralChild() {
+        var graph = Graph.builder(ArgumentType.Literal("foo"))
+                .append(ArgumentType.Enum("a", A.class))
+                .append(ArgumentType.Literal("l"))
+                .append(ArgumentType.Enum("b", B.class))
+                .build();
+        assertPacketGraph("""
+                foo l=%
+                0->foo
+                a b c d e f=§
+                foo->a b c d e f l
+                """, graph);
+    }
 
     static void assertPacketGraph(String expected, Graph... graphs) {
         var packet = GraphConverter.createPacket(Graph.merge(graphs), null);