fix: null-check for player's chunk team data on logout

Should not normally be null, but external factors could force a player
disconnect before they have an FTB team assigned.

FTBTeam/FTB-Mods-Issues#932

common/src/main/java/dev/ftb/mods/ftbchunks/FTBChunks.java

@@ -224,13 +224,19 @@ public void loggedOut(ServerPlayer player) {
 		}
 
 		ChunkTeamDataImpl data = ClaimedChunkManagerImpl.getInstance().getOrCreateData(player);
-		data.setForceLoadMember(player.getUUID(), FTBChunksWorldConfig.canPlayerOfflineForceload(player));
-		ClaimedChunkManagerImpl.getInstance().clearForceLoadedCache();
-		LongRangePlayerTracker.INSTANCE.stopTracking(player);
-
-		if (data.getTeam().getOnlineMembers().size() == 1 && !data.canDoOfflineForceLoading()) {
-			// last player on the team to log out; unforce chunks if the team can't do offline chunk-loading
-			data.updateChunkTickets(false);
+		// shouldn't normally be null here, but external problems could force a player logout before they have a team
+		// https://github.com/FTBTeam/FTB-Mods-Issues/issues/932
+		if (data != null) {
+			data.setForceLoadMember(player.getUUID(), FTBChunksWorldConfig.canPlayerOfflineForceload(player));
+			ClaimedChunkManagerImpl.getInstance().clearForceLoadedCache();
+			LongRangePlayerTracker.INSTANCE.stopTracking(player);
+
+			if (data.getTeam().getOnlineMembers().size() == 1 && !data.canDoOfflineForceLoading()) {
+				// last player on the team to log out; unforce chunks if the team can't do offline chunk-loading
+				data.updateChunkTickets(false);
+			}
+		} else {
+			FTBChunks.LOGGER.warn("on player disconnect: player '{}' has no team?", player.getGameProfile().getName());
 		}
 	}
 

common/src/main/java/dev/ftb/mods/ftbchunks/api/ClaimedChunkManager.java

@@ -33,9 +33,12 @@ public interface ClaimedChunkManager {
     /**
      * Get the FTB Chunks team data for the given player, creating a new instance if necessary. This will get the
      * data for the party team the player is in, if applicable.
+     * <p>
+     * This should not normally return null, but it is a possibility if external problems cause the player to be
+     * disconnected before they are assigned an FTB Team. So the return value should be checked.
      *
      * @param player the player
-     * @return the FTB Chunks data for the team
+     * @return the FTB Chunks data for the team, or null if something went wrong
      */
     ChunkTeamData getOrCreateData(ServerPlayer player);
 
@@ -44,7 +47,7 @@ public interface ClaimedChunkManager {
      * for the player's personal team, even if they are currently in a party team.
      *
      * @param id a player UUID
-     * @return the FTB Chunks data for the player
+     * @return the FTB Chunks data for the player, or null if something went wrong
      */
     ChunkTeamData getPersonalData(UUID id);