metasync: Strip whitespace from values

Fix #358

tests/test_metasync.py

@@ -1,5 +1,8 @@
 # -*- coding: utf-8 -*-
 
+from hypothesis import given
+import hypothesis.strategies as st
+
 import pytest
 
 from vdirsyncer.metasync import MetaSyncConflict, metasync
@@ -82,3 +85,17 @@ def test_conflict_x_wins(wins):
     assert a.get_meta('foo') == b.get_meta('foo') == status['foo'] == (
         'bar' if wins == 'a' else 'baz'
     )
+
+
+@given(s=st.text().filter(lambda x: x.strip() == x), key=st.text())
+def test_trailing_newline(s, key):
+    a = MemoryStorage()
+    b = MemoryStorage()
+    status = {}
+    a.set_meta(key, s + u'\n')
+    b.set_meta(key, s)
+    a.set_meta = b.set_meta = blow_up
+
+    metasync(a, b, status, keys=[key])
+
+    assert status[key] == s

vdirsyncer/metasync.py

@@ -1,4 +1,5 @@
 from . import exceptions, log
+from .utils.compat import text_type
 
 logger = log.get(__name__)
 
@@ -33,8 +34,8 @@ def metasync(storage_a, storage_b, status, keys, conflict_resolution=None):
             _b_to_a()
 
     for key in keys:
-        a = storage_a.get_meta(key)
+        a = _normalize_value(storage_a.get_meta(key))
-        b = storage_b.get_meta(key)
+        b = _normalize_value(storage_b.get_meta(key))
         s = status.get(key)
         logger.debug(u'Key: {}'.format(key))
         logger.debug(u'A: {}'.format(a))
@@ -52,3 +53,11 @@ def metasync(storage_a, storage_b, status, keys, conflict_resolution=None):
 
     for key in set(status) - set(keys):
         del status[key]
+
+
+def _normalize_value(value):
+    if value is None:
+        return value
+    else:
+        assert isinstance(value, text_type)
+        return value.strip()