warn instead of raising... for now

edit warning per suggestion

1 files changed, 13 insertions, 11 deletions

diff --git a/dateutil/parser/_parser.py b/dateutil/parser/_parser.py
index a5ec2fb..de81fdc 100644
--- a/dateutil/parser/_parser.py
+++ b/dateutil/parser/_parser.py
@@ -34,6 +34,7 @@ import datetime
 import re
 import string
 import time
+import warnings
 
 from calendar import monthrange
 from io import StringIO
@@ -613,14 +614,6 @@ class parser(object):
         if not ignoretz:
             ret = self._build_tzaware(ret, res, tzinfos)
 
-            elif not res.tzname and not res.tzoffset:
-                # i.e. no timezone information was found.
-                pass
-            else:
-                # tz-like string was parsed but we don't know what to do
-                # with it
-                raise ValueError(res.tzname)
-
         if kwargs.get('fuzzy_with_tokens', False):
             return ret, skipped_tokens
         else:
@@ -1153,9 +1146,18 @@ class parser(object):
         elif res.tzoffset:
             aware = naive.replace(tzinfo=tz.tzoffset(res.tzname, res.tzoffset))
 
-        else:
-            # TODO: this is really only the right thing to do if no tz
-            # information was found.
+        elif not res.tzname and not res.tzoffset:
+            # i.e. no timezone information was found.
+            aware = naive
+
+        elif res.tzname:
+            # tz-like string was parsed but we don't know what to do
+            # with it
+            warnings.warn("tzname {tzname} identified but not understood.  "
+                          "Pass `tzinfos` argument in order to correctly "
+                          "return a timezone-aware datetime.  In a future "
+                          "version, this raise an "
+                          "exception.".format(tzname=res.tzname))
             aware = naive
 
         return aware