Add option to use legacy behavior for TypeMetadata loading

 - When option is enabled, reverts HearthSim#101

README.md

@@ -3,6 +3,10 @@
 
 A library to deserialize Unity3D Assets and AssetBundles files (*.unity3d).
 
+## Fork Information
+
+- This fork is **meant to be used for 07th-mod project** only, I wouldn't use this for other projects.
+
 ## Dependencies
 
 * [python-lz4](https://github.com/python-lz4/python-lz4) (For UnityFS-compressed files)

unitypack/asset.py

@@ -18,8 +18,9 @@
 
 class Asset:
 	@classmethod
-	def from_bundle(cls, bundle, buf):
+	def from_bundle(cls, bundle, buf, legacy_mode):
 		ret = cls()
+		ret.legacy_mode = legacy_mode
 		ret.bundle = bundle
 		ret.environment = bundle.environment
 		offset = buf.tell()
@@ -52,8 +53,9 @@ def from_bundle(cls, bundle, buf):
 		return ret
 
 	@classmethod
-	def from_file(cls, file, environment=None):
+	def from_file(cls, file, legacy_mode, environment=None):
 		ret = cls()
+		ret.legacy_mode = legacy_mode
 		ret.name = file.name
 		ret._buf_ofs = file.tell()
 		ret._buf = BinaryReader(file)
@@ -78,6 +80,7 @@ def get_asset(self, path):
 			return None
 
 	def __init__(self):
+		self.legacy_mode = False
 		self._buf_ofs = None
 		self._objects = {}
 		self.adds = []

unitypack/type.py

@@ -151,9 +151,16 @@ def load(self, buf, format=None):
 					tree.load(buf)
 					self.type_trees[class_id] = tree
 
-				# 4 unidentified bytes at the end of a type tree in 2019.4
-				if format >= 21:
-					unk1 = buf.read(4)
+				# I had an issue with only one asset being detected when trying to open a 2019.4.36f1 file
+				# because this would skip over the 'num_objects' field, resulting in num_objects being set to '1'
+				#
+				# I'm not sure how to fix this properly, so I've just added an option to disable it
+				# (perhaps you could copy how UABE does it? since UABE seems to work fine with the same file)
+				if not self.asset.legacy_mode:
+					# The below code change was added in https://github.com/HearthSim/UnityPack/pull/101
+					# 4 unidentified bytes at the end of a type tree in 2019.4
+					if format >= 21:
+						unk1 = buf.read(4)
 
 		else:
 			num_fields = buf.read_int()