git.Tree: Fixed critical issue when reading trees from binary data. The previous version was making assumptions that would only be true for old git repositories it sesms. The new version of the algorithm deals with this gracefully.

Author: Byron

lib/git/objects/tree.py

@@ -44,7 +44,7 @@ class Tree(base.IndexObject, diff.Diffable, utils.Traversable):
 	commit_id = 016		
 	blob_id = 010
 	symlink_id = 012
-	tree_id = 040
+	tree_id = 004
 
 
 	def __init__(self, repo, sha, mode=0, path=None):
@@ -97,18 +97,17 @@ def _iter_from_data(self):
 		i = 0
 		while i < len_data:
 			mode = 0
-			mode_boundary = i + 6
-			
-			# read type
-			type_id = ((ord(data[i])-ord_zero)<<3) + (ord(data[i+1])-ord_zero)
-			i += 2
 
+			# read mode
+			# Some git versions truncate the leading 0, some don't
+			# The type will be extracted from the mode later
 			while data[i] != ' ':
 				# move existing mode integer up one level being 3 bits
 				# and add the actual ordinal value of the character
 				mode = (mode << 3) + (ord(data[i]) - ord_zero)
 				i += 1
 			# END while reading mode
+			type_id = mode >> 12 
 
 			# byte is space now, skip it
 			i += 1
@@ -127,7 +126,6 @@ def _iter_from_data(self):
 			sha = data[i:i+20]
 			i = i + 20
 
-			mode |= type_id<<12
 			hexsha = sha_to_hex(sha)
 			if type_id == self.blob_id or type_id == self.symlink_id:
 				yield blob.Blob(self.repo, hexsha, mode, path)
@@ -137,7 +135,7 @@ def _iter_from_data(self):
 				# todo 
 				yield None
 			else:
-				raise TypeError( "Unknown type found in tree data: %i" % type_id )
+				raise TypeError( "Unknown type found in tree data %i for path '%s'" % (type_id, path))
 		# END for each byte in data stream