Merge branch 'master' into 1.17

# Conflicts:
#	src/main/java/carpet/helpers/FeatureGenerator.java

src/main/java/carpet/helpers/FeatureGenerator.java

@@ -40,7 +40,7 @@ import java.util.Map;
 
 public class FeatureGenerator
 {
-
+    public static final Object boo = new Object();
     synchronized public static Boolean plop(String featureName, ServerWorld world, BlockPos pos)
     {
         Thing custom = featureMap.get(featureName);
@@ -147,8 +147,10 @@ public class FeatureGenerator
         long seed = world.getSeed();
         ChunkGenerator generator = world.getChunkManager().getChunkGenerator();
         StructureConfig params = generator.getStructuresConfig().getForType(structure);
-        if (!generator.getBiomeSource().hasStructureFeature(structure))
-            return null;
+        synchronized(boo) {
+            if (!generator.getBiomeSource().hasStructureFeature(structure))
+                return null;
+        }
         BiomeAccess biomeAccess = world.getBiomeAccess().withSource(generator.getBiomeSource());
         ChunkRandom chunkRandom = new ChunkRandom();
         ChunkPos chunkPos = new ChunkPos(pos);
@@ -163,7 +165,9 @@ public class FeatureGenerator
             if (!computeBox) return StructureStart.DEFAULT;
             StructureManager manager = world.getStructureManager();
             StructureStart<T> structureStart3 = structure.getStructureStartFactory().create((StructureFeature<T>) configuredFeature.feature, chunkPos, 0, seed);
-            structureStart3.init(world.getRegistryManager(), generator, manager, chunkPos, biome, (T) configuredFeature.config, world);
+            synchronized (boo) {
+                structureStart3.init(world.getRegistryManager(), generator, manager, chunkPos, biome, (T) configuredFeature.config, world);
+            }
             if (!structureStart3.hasChildren()) return null;
             return structureStart3;
         }

src/main/java/carpet/script/argument/FileArgument.java

@@ -1,8 +1,6 @@
 package carpet.script.argument;
 
 import carpet.CarpetServer;
-import carpet.script.Context;
-import carpet.script.LazyValue;
 import carpet.script.bundled.Module;
 import carpet.script.exception.InternalExpressionException;
 import carpet.script.exception.ThrowStatement;
@@ -180,14 +178,11 @@ public class FileArgument
                 Map<String, String> env = new HashMap<>();
                 if (reason == Reason.CREATE) env.put("create", "true");
                 zipPath = resolve(getDescriptor(module, zipContainer));
+                if (!Files.exists(zipPath) && reason != Reason.CREATE) return null; // no zip file
                 try {
                     zfs = FileSystems.newFileSystem(URI.create("jar:"+ zipPath.toUri().toString()), env);
                 }
-                catch (FileSystemNotFoundException fsnfe)
-                {
-                    return null;
-                }
-                catch (IOException e)
+                catch (FileSystemNotFoundException | IOException fsnfe)
                 {
                     return null; // undr java 16 no file throws IOException - will take care of it later
                     //throw new ThrowStatement("Unable to open zip file: "+zipContainer, Throwables.IO_EXCEPTION);