Merge pull request #90 from eendebakpt/import_time_lazy_list

Draft: prevent evaluation of lazy list in pytz.timezone

gen_tzinfo.py

@@ -121,10 +121,10 @@ def add_allzones(filename):
             cz.append(zone)
     cz.sort()
 
-    print('all_timezones = \\', file=outf)
+    print('all_timezones_unchecked = \\', file=outf)
     pprint(sorted(allzones()), outf)
     print('''all_timezones = LazyList(
-        tz for tz in all_timezones if resource_exists(tz))
+        tz for tz in all_timezones_unchecked if resource_exists(tz))
         ''', file=outf)
     print('all_timezones_set = LazySet(all_timezones)', file=outf)
     # Per lp:1835784 we can't afford to do this at import time

src/pytz/__init__.py

@@ -202,7 +202,7 @@ def _case_insensitive_zone_lookup(zone):
     """case-insensitively matching timezone, else return zone unchanged"""
     global _all_timezones_lower_to_standard
     if _all_timezones_lower_to_standard is None:
-        _all_timezones_lower_to_standard = dict((tz.lower(), tz) for tz in all_timezones)  # noqa
+        _all_timezones_lower_to_standard = dict((tz.lower(), tz) for tz in all_timezones_unchecked)  # noqa
     return _all_timezones_lower_to_standard.get(zone.lower()) or zone  # noqa