From cd5094252ac002741bd0fc89c0123b7d55b56a55 Mon Sep 17 00:00:00 2001
From: wizjany <wizjany@gmail.com>
Date: Wed, 6 Jul 2016 11:14:11 -0400
Subject: [PATCH] Fix NPE when //genbiome expression was false. Fixes
 WORLDEDIT-3467.

---
 .../src/main/java/com/sk89q/worldedit/EditSession.java        | 2 +-
 .../java/com/sk89q/worldedit/command/GenerationCommands.java  | 4 ++--
 .../sk89q/worldedit/regions/shape/ArbitraryBiomeShape.java    | 2 +-
 3 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/worldedit-core/src/main/java/com/sk89q/worldedit/EditSession.java b/worldedit-core/src/main/java/com/sk89q/worldedit/EditSession.java
index 3253fb61a8..abb4f4909f 100644
--- a/worldedit-core/src/main/java/com/sk89q/worldedit/EditSession.java
+++ b/worldedit-core/src/main/java/com/sk89q/worldedit/EditSession.java
@@ -2301,7 +2301,7 @@ protected BaseBiome getBiome(int x, int z, BaseBiome defaultBiomeType) {
 
                 try {
                     if (expression.evaluate(scaled.getX(), scaled.getZ()) <= 0) {
-                        return null;
+                        return null; // TODO should return OUTSIDE? seems to cause issues otherwise, workedaround for now
                     }
 
                     // TODO: Allow biome setting via a script variable (needs BiomeType<->int mapping)
diff --git a/worldedit-core/src/main/java/com/sk89q/worldedit/command/GenerationCommands.java b/worldedit-core/src/main/java/com/sk89q/worldedit/command/GenerationCommands.java
index 09abf3b992..edda882a8d 100644
--- a/worldedit-core/src/main/java/com/sk89q/worldedit/command/GenerationCommands.java
+++ b/worldedit-core/src/main/java/com/sk89q/worldedit/command/GenerationCommands.java
@@ -316,12 +316,12 @@ public void generate(Player player, LocalSession session, EditSession editSessio
 
     @Command(
         aliases = { "/generatebiome", "/genbiome", "/gb" },
-        usage = "<block> <expression>",
+        usage = "<biome> <expression>",
         desc = "Sets biome according to a formula.",
         help =
             "Generates a shape according to a formula that is expected to\n" +
             "return positive numbers (true) if the point is inside the shape\n" +
-            "Optionally set type/data to the desired block.\n" +
+            "Sets the biome of blocks in that shape.\n" +
             "Flags:\n" +
             "  -h to generate a hollow shape\n" +
             "  -r to use raw minecraft coordinates\n" +
diff --git a/worldedit-core/src/main/java/com/sk89q/worldedit/regions/shape/ArbitraryBiomeShape.java b/worldedit-core/src/main/java/com/sk89q/worldedit/regions/shape/ArbitraryBiomeShape.java
index 485f5834a8..942b55c6c3 100644
--- a/worldedit-core/src/main/java/com/sk89q/worldedit/regions/shape/ArbitraryBiomeShape.java
+++ b/worldedit-core/src/main/java/com/sk89q/worldedit/regions/shape/ArbitraryBiomeShape.java
@@ -136,7 +136,7 @@ public int generate(EditSession editSession, BaseBiome baseBiome, boolean hollow
 
             if (!hollow) {
                 final BaseBiome material = getBiome(x, z, baseBiome);
-                if (material != OUTSIDE) {
+                if (material != null && material != OUTSIDE) {
                     editSession.getWorld().setBiome(position, material);
                     ++affected;
                 }