# HG changeset patch
# User Paul Boddie <paul@boddie.org.uk>
# Date 1374531478 -7200
# Node ID e472e3641070431eb5f39d73b210e5ed20d85c8b
# Parent  88b96032ae75536b357d592649cac4f0a16ea072
Introduced an explicit error condition where pytz is not installed and an
attempt is made to inspect Olson time zone information.

diff -r 88b96032ae75 -r e472e3641070 DateSupport.py
--- a/DateSupport.py	Tue Jul 16 17:10:54 2013 +0200
+++ b/DateSupport.py	Tue Jul 23 00:17:58 2013 +0200
@@ -632,7 +632,7 @@
         """
 
         olson = self.olson_identifier()
-        if olson and pytz:
+        if olson:
             tz = pytz.timezone(olson)
             data = self.padded().as_tuple()[:6]
             dt = datetime.datetime(*data)
@@ -665,6 +665,8 @@
         period of ambiguity.
         """
 
+        self._check_pytz()
+
         try:
             return self._as_olson_datetime()
         except (pytz.UnknownTimeZoneError, pytz.AmbiguousTimeError):
@@ -679,6 +681,8 @@
 
         "Return whether the time is local and ambiguous."
 
+        self._check_pytz()
+
         try:
             self._as_olson_datetime()
         except (pytz.UnknownTimeZoneError, pytz.AmbiguousTimeError):
@@ -686,6 +690,11 @@
 
         return 0
 
+    def _check_pytz(self):
+        if not pytz:
+            raise NotImplementedError, "pytz must be installed for Olson " \
+                "time zones to be supported"
+
 class Timespan(ActsAsTimespan, Convertible):
 
     """
diff -r 88b96032ae75 -r e472e3641070 README.txt
--- a/README.txt	Tue Jul 16 17:10:54 2013 +0200
+++ b/README.txt	Tue Jul 23 00:17:58 2013 +0200
@@ -64,6 +64,12 @@
 If time zone handling is not required, pytz need not be installed. It is,
 however, highly recommended that pytz be installed.
 
+New in MoinSupport 0.4.1 (Changes since MoinSupport 0.4)
+--------------------------------------------------------
+
+  * Introduced an explicit error condition where pytz is not installed and an
+    attempt is made to inspect Olson time zone information.
+
 New in MoinSupport 0.4 (Changes since MoinSupport 0.3)
 ------------------------------------------------------