Correctly handle multiline UIDs

See #74

tests/utils/test_vobject.py

@@ -85,3 +85,11 @@ def test_hash_item():
     b = u'\n'.join(line for line in a.splitlines()
                    if u'PRODID' not in line and u'VERSION' not in line)
     assert vobject.hash_item(a) == vobject.hash_item(b)
+
+
+def test_multiline_uid():
+    a = (u'BEGIN:FOO\r\n'
+         u'UID:123456789abcd\r\n'
+         u' efgh\r\n'
+         u'END:FOO\r\n')
+    assert vobject.Item(a).uid == u'123456789abcdefgh'

vdirsyncer/utils/vobject.py

@@ -91,6 +91,15 @@ class Item(object):
     def uid(self):
         '''Global identifier of the item, across storages, doesn't change after
         a modification of the item.'''
+        stack = [self.parsed]
+        while stack:
+            component = stack.pop()
+            if not component:
+                continue
+            uid = component.get('UID', None)
+            if uid:
+                return uid
+            stack.extend(component.subcomponents)
 
         for line in self.raw.splitlines():
             if line.startswith(u'UID:'):