Check if the key exists first

chunk.py

@@ -330,16 +330,6 @@ class ChunkRenderer(object):
         """
         blockid = self.blockid
 
-        if self.oldimg:
-            # An image exists? Instead of checking the hash which is kinda
-            # expensive (for tens of thousands of chunks, yes it is) check if
-            # the mtime of the chunk file is newer than the mtime of oldimg
-            if os.path.getmtime(self.chunkfile) <= os.path.getmtime(self.oldimg_path):
-                # chunkfile is older than the image, don't even bother checking
-                # the hash
-                logging.debug("Using cached image")
-                return self.oldimg_path
-
         # Reasons for the code to get to this point:
         # 1) An old image doesn't exist
         # 2) An old image exists, but the chunk was more recently modified (the

world.py

@@ -296,7 +296,7 @@ class WorldRenderer(object):
                         continue
 
                 oldimg = chunk.find_oldimage(chunkfile, cached, self.caves)
-                if os.path.getmtime(chunkfile) <= os.path.getmtime(oldimg[1]):
+                if oldimg[1] and (os.path.getmtime(chunkfile) <= os.path.getmtime(oldimg[1])):
                     result = oldimg[1]
                 else:
                     result = chunk.render_and_save(chunkfile, self.cachedir, self, oldimg, queue=q)
@@ -327,7 +327,7 @@ class WorldRenderer(object):
                         continue
 
                 oldimg = chunk.find_oldimage(chunkfile, cached, self.caves)
-                if os.path.getmtime(chunkfile) <= os.path.getmtime(oldimg[1]):
+                if oldimg[1] and (os.path.getmtime(chunkfile) <= os.path.getmtime(oldimg[1])):
                     result = oldimg[1]
                 else:
                     result = pool.apply_async(chunk.render_and_save,