From ed6a65a6abca6e55576754def00f07970057b478 Mon Sep 17 00:00:00 2001
From: Markus Unterwaditzer <markus@unterwaditzer.net>
Date: Thu, 4 Jun 2015 10:55:29 +0200
Subject: [PATCH] Add warning about missing etag

---
 vdirsyncer/storage/dav.py | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/vdirsyncer/storage/dav.py b/vdirsyncer/storage/dav.py
index 640c062..6af589e 100644
--- a/vdirsyncer/storage/dav.py
+++ b/vdirsyncer/storage/dav.py
@@ -446,6 +446,9 @@ class DavStorage(Storage):
         etag = response.headers.get('etag', None)
         href = self._normalize_href(_decode_href(response.url))
         if not etag:
+            dav_logger.warning('Race condition detected with server {}, '
+                               'consider using an alternative.'
+                               .format(self.session.parsed_url.netloc))
             item2, etag = self.get(href)
             assert item2.uid == item.uid
         return href, etag