fix NPE

common/src/main/java/com/dfsek/terra/api/util/collections/ProbabilityCollection.java

@@ -49,7 +49,10 @@ public class ProbabilityCollection<E> implements Collection<E> {
 
     public <T> ProbabilityCollection<T> map(Function<E, T> mapper, boolean carryNull) {
         ProbabilityCollection<T> newCollection = new ProbabilityCollection<>();
-        cont.forEach((o, count) -> newCollection.add(mapper.apply(o), count.get()));
+        cont.forEach((o, count) -> {
+            if(o != null) newCollection.add(mapper.apply(o), count.get());
+            else if(carryNull) newCollection.add(null, count.get());
+        });
         return newCollection;
     }
 

common/src/main/java/com/dfsek/terra/config/loaders/config/biome/templates/stage/mutator/BorderListMutatorTemplate.java

@@ -30,8 +30,8 @@ public class BorderListMutatorTemplate extends MutatorStageTemplate {
     public BiomeMutator build(long seed) {
         Map<TerraBiome, ProbabilityCollection<TerraBiome>> replaceMap = new HashMap<>();
 
-        replace.forEach((keyBuilder, replacements) -> replaceMap.put(keyBuilder.apply(seed), replacements.map(replacement -> replacement.get().apply(seed), true)));
+        replace.forEach((keyBuilder, replacements) -> replaceMap.put(keyBuilder.apply(seed), replacements.map(MetaValue::get).map(replacement -> replacement.apply(seed))));
 
-        return new BorderListMutator(replaceMap, from.get(), defaultReplace.get(), noise.get().apply(seed), defaultTo.map(biomeBuilder -> biomeBuilder.get().apply(seed), true));
+        return new BorderListMutator(replaceMap, from.get(), defaultReplace.get(), noise.get().apply(seed), defaultTo.map(MetaValue::get).map(biomeBuilder -> biomeBuilder.apply(seed)));
     }
 }

common/src/main/java/com/dfsek/terra/config/loaders/config/biome/templates/stage/mutator/BorderMutatorTemplate.java

@@ -20,6 +20,6 @@ public class BorderMutatorTemplate extends MutatorStageTemplate {
 
     @Override
     public BiomeMutator build(long seed) {
-        return new BorderMutator(from.get(), replace.get(), noise.get().apply(seed), to.map(biomeBuilder -> biomeBuilder.get().apply(seed), true));
+        return new BorderMutator(from.get(), replace.get(), noise.get().apply(seed), to.map(MetaValue::get).map(biomeBuilder -> biomeBuilder.apply(seed)));
     }
 }

common/src/main/java/com/dfsek/terra/config/loaders/config/biome/templates/stage/mutator/ReplaceListMutatorTemplate.java

@@ -26,8 +26,8 @@ public class ReplaceListMutatorTemplate extends MutatorStageTemplate {
     public BiomeMutator build(long seed) {
         Map<TerraBiome, ProbabilityCollection<TerraBiome>> replaceMap = new HashMap<>();
 
-        replace.forEach((biomeBuilder, biomeBuilders) -> replaceMap.put(biomeBuilder.apply(seed), biomeBuilders.map(builder -> builder.get().apply(seed), true)));
+        replace.forEach((biomeBuilder, biomeBuilders) -> replaceMap.put(biomeBuilder.apply(seed), biomeBuilders.map(MetaValue::get).map(builder -> builder.apply(seed))));
 
-        return new ReplaceListMutator(replaceMap, defaultFrom.get(), defaultTo.map(biomeBuilder -> biomeBuilder.get().apply(seed), true), noise.get().apply(seed));
+        return new ReplaceListMutator(replaceMap, defaultFrom.get(), defaultTo.map(MetaValue::get).map(biomeBuilder -> biomeBuilder.apply(seed)), noise.get().apply(seed));
     }
 }

common/src/main/java/com/dfsek/terra/config/loaders/config/biome/templates/stage/mutator/ReplaceMutatorTemplate.java

@@ -17,6 +17,6 @@ public class ReplaceMutatorTemplate extends MutatorStageTemplate {
 
     @Override
     public BiomeMutator build(long seed) {
-        return new ReplaceMutator(from.get(), to.map(biomeBuilder -> biomeBuilder.get().apply(seed), true), noise.get().apply(seed));
+        return new ReplaceMutator(from.get(), to.map(MetaValue::get).map(biomeBuilder -> biomeBuilder.apply(seed)), noise.get().apply(seed));
     }
 }