Add PlayerConnectionCloseEvent

This event is invoked when a player has disconnected. It is guaranteed that,
if the server is in online-mode, that the provided uuid and username have been
validated.

The event is invoked for players who have not yet logged into the world, whereas
PlayerQuitEvent is only invoked on players who have logged into the world.

The event is invoked for players who have already logged into the world,
although whether or not the player exists in the world at the time of
firing is undefined. (That is, whether the plugin can retrieve a Player object
using the event parameters is undefined). However, it is guaranteed that this
event is invoked AFTER PlayerQuitEvent, if the player has already logged into
the world.

This event is guaranteed to never fire unless AsyncPlayerPreLoginEvent has
been called beforehand, and this event may not be called in parallel with
AsyncPlayerPreLoginEvent for the same connection.

Cancelling the AsyncPlayerPreLoginEvent guarantees the corresponding
PlayerConnectionCloseEvent is never called.

The event may be invoked asynchronously or synchronously. As it stands,
it is never invoked asynchronously. However, plugins should check
Event#isAsynchronous to be future-proof.

On purpose, the deprecated PlayerPreLoginEvent event is left out of the
API spec for this event. Plugins should not be using that event, and
how PlayerPreLoginEvent interacts with PlayerConnectionCloseEvent
is undefined.

== AT ==
public net.minecraft.server.network.ServerLoginPacketListenerImpl$State
public net.minecraft.server.network.ServerLoginPacketListenerImpl state

paper-server/patches/sources/net/minecraft/network/Connection.java.patch

@@ -117,11 +117,32 @@
              public void write(ChannelHandlerContext channelhandlercontext, Object object, ChannelPromise channelpromise) throws Exception {
                  super.write(channelhandlercontext, object, channelpromise);
              }
-@@ -661,6 +691,7 @@
+@@ -660,7 +690,28 @@
+                     });
  
                      packetlistener1.onDisconnect(disconnectiondetails);
-                 }
++                }
 +                this.pendingActions.clear(); // Free up packet queue.
++                // Paper start - Add PlayerConnectionCloseEvent
++                final PacketListener packetListener = this.getPacketListener();
++                if (packetListener instanceof net.minecraft.server.network.ServerCommonPacketListenerImpl commonPacketListener) {
++                    /* Player was logged in, either game listener or configuration listener */
++                    final com.mojang.authlib.GameProfile profile = commonPacketListener.getOwner();
++                    new com.destroystokyo.paper.event.player.PlayerConnectionCloseEvent(profile.getId(),
++                        profile.getName(), ((InetSocketAddress) this.address).getAddress(), false).callEvent();
++                } else if (packetListener instanceof net.minecraft.server.network.ServerLoginPacketListenerImpl loginListener) {
++                    /* Player is login stage */
++                    switch (loginListener.state) {
++                        case VERIFYING:
++                        case WAITING_FOR_DUPE_DISCONNECT:
++                        case PROTOCOL_SWITCHING:
++                        case ACCEPTED:
++                            final com.mojang.authlib.GameProfile profile = loginListener.authenticatedProfile; /* Should be non-null at this stage */
++                            new com.destroystokyo.paper.event.player.PlayerConnectionCloseEvent(profile.getId(), profile.getName(),
++                                ((InetSocketAddress) this.address).getAddress(), false).callEvent();
++                    }
+                 }
++                // Paper end - Add PlayerConnectionCloseEvent
  
              }
          }

paper-server/patches/sources/net/minecraft/server/network/ServerLoginPacketListenerImpl.java.patch

@@ -56,8 +56,12 @@
      private static final int MAX_TICKS_BEFORE_LOGIN = 600;
      private final byte[] challenge;
      final MinecraftServer server;
-@@ -60,6 +89,7 @@
-     private GameProfile authenticatedProfile;
+@@ -57,9 +86,10 @@
+     @Nullable
+     String requestedUsername;
+     @Nullable
+-    private GameProfile authenticatedProfile;
++    public GameProfile authenticatedProfile; // Paper - public
      private final String serverId;
      private final boolean transferred;
 +    private ServerPlayer player; // CraftBukkit