From 7430b66862346fe3a6a100ab25e35a8711446717 Mon Sep 17 00:00:00 2001
From: Johannes Raggam <raggam-nl@adm.at>
Date: Thu, 22 Nov 2012 17:33:41 +0100
Subject: [PATCH] Correctly handle tzinfo objects parsed with dateutil. Fixes
 #77. Tests missing.

---
 docs/changelog.rst      |  3 +++
 src/icalendar/parser.py |  8 ++++++++
 src/icalendar/prop.py   | 21 ++++++++++-----------
 3 files changed, 21 insertions(+), 11 deletions(-)

diff --git a/docs/changelog.rst b/docs/changelog.rst
index 564d028..76de7ca 100644
--- a/docs/changelog.rst
+++ b/docs/changelog.rst
@@ -4,6 +4,9 @@ Changelog
 3.2dev
 ------
 
+* Correctly handle tzinfo objects parsed with dateutil. Fixes #77.
+  [warvariuc, thet]
+
 * Text values are escaped correclty. Fixes #74.
   [warvariuc]
 
diff --git a/src/icalendar/parser.py b/src/icalendar/parser.py
index 2d407be..731124a 100644
--- a/src/icalendar/parser.py
+++ b/src/icalendar/parser.py
@@ -32,6 +32,14 @@ def unescape_char(text):
                .replace(r'\;', ';')\
                .replace('\\\\', '\\')
 
+def tzinfo_from_dt(dt):
+    tzid = None
+    if hasattr(dt.tzinfo, 'zone'):
+        tzid = dt.tzinfo.zone # pytz implementation
+    elif hasattr(dt.tzinfo, 'tzname'):
+        tzid = dt.tzinfo.tzname(dt) # dateutil implementation
+    return tzid
+
 
 def foldline(text, length=75, newline='\r\n'):
     """Make a string folded per RFC5545 (each line must be less than 75 octets)
diff --git a/src/icalendar/prop.py b/src/icalendar/prop.py
index 3ccf779..eaa926a 100644
--- a/src/icalendar/prop.py
+++ b/src/icalendar/prop.py
@@ -53,6 +53,7 @@ from icalendar.caselessdict import CaselessDict
 from icalendar.parser import Parameters
 from icalendar.parser import escape_char
 from icalendar.parser import unescape_char
+from icalendar.parser import tzinfo_from_dt
 
 
 SequenceTypes = [TupleType, ListType]
@@ -557,18 +558,15 @@ class vDatetime:
 
     def to_ical(self):
         dt = self.dt
-        if hasattr(dt.tzinfo, 'zone'):
-            tzid = dt.tzinfo and dt.tzinfo.zone or None
-        else:
-            tzid = dt.tzinfo and dt.tzinfo.tzname(self.dt) or None
+        tzid = tzinfo_from_dt(dt)
 
         s = "%04d%02d%02dT%02d%02d%02d" % (
-            self.dt.year,
-            self.dt.month,
-            self.dt.day,
-            self.dt.hour,
-            self.dt.minute,
-            self.dt.second
+            dt.year,
+            dt.month,
+            dt.day,
+            dt.hour,
+            dt.minute,
+            dt.second
         )
         if tzid == 'UTC':
             s += "Z"
@@ -784,7 +782,8 @@ class vPeriod:
 
         self.params = Parameters()
         # set the timezone identifier
-        tzid = start.tzinfo and start.tzinfo.zone or None
+        # does not support different timezones for start and end
+        tzid = tzinfo_from_dt(start)
         if tzid:
             self.params['TZID'] = tzid