Properly fall back to `long` metazone names when short forms are no-inherit

Thanks to @stringtheory for the bug report!

Fixes #428

diff --git a/babel/dates.py b/babel/dates.py
index 523e4562de5087f21a0ad498542f0ef9fc13c113..c84ca48652df30ce66727867396b106cefac21f6 100644 (file)
--- a/babel/dates.py
+++ b/babel/dates.py
@@ -30,6 +30,16 @@ from babel.util import UTC, LOCALTZ
 from babel._compat import string_types, integer_types, number_types
 
 
+# "If a given short metazone form is known NOT to be understood in a given
+#  locale and the parent locale has this value such that it would normally
+#  be inherited, the inheritance of this value can be explicitly disabled by
+#  use of the 'no inheritance marker' as the value, which is 3 simultaneous [sic]
+#  empty set characters ( U+2205 )."
+#  - http://www.unicode.org/reports/tr35/tr35-dates.html#Metazone_Names
+
+NO_INHERITANCE_MARKER = u'\u2205\u2205\u2205'
+
+
 LC_TIME = default_locale('LC_TIME')
 
 # Aliases for use in scopes where the modules are shadowed by local variables
@@ -642,8 +652,13 @@ def get_timezone_name(dt_or_tzinfo=None, width='long', uncommon=False,
     if metazone:
         metazone_info = locale.meta_zones.get(metazone, {})
         if width in metazone_info:
-            if zone_variant in metazone_info[width]:
-                return metazone_info[width][zone_variant]
+            name = metazone_info[width].get(zone_variant)
+            if width == 'short' and name == NO_INHERITANCE_MARKER:
+                # If the short form is marked no-inheritance,
+                # try to fall back to the long name instead.
+                name = metazone_info.get('long', {}).get(zone_variant)
+            if name:
+                return name
 
     # If we have a concrete datetime, we assume that the result can't be
     # independent of daylight savings time, so we return the GMT offset

diff --git a/tests/test_dates.py b/tests/test_dates.py
index b0d093ec2805bcad0ddb36990883a962cee95c6f..f74cd396dee81ff1a81777f41e2f3f723f0f51ae 100644 (file)
--- a/tests/test_dates.py
+++ b/tests/test_dates.py
@@ -15,9 +15,12 @@ import calendar
 from datetime import date, datetime, time, timedelta
 import unittest
 
+import pytest
+import pytz
 from pytz import timezone
 
 from babel import dates, Locale
+from babel.dates import NO_INHERITANCE_MARKER
 from babel.util import FixedOffsetTimezone
 
 
@@ -761,3 +764,22 @@ def test_format_current_moment(monkeypatch):
     # Freeze time! Well, some of it anyway.
     monkeypatch.setattr(datetime_module, "datetime", frozen_datetime)
     assert dates.format_datetime(locale="en_US") == dates.format_datetime(frozen_instant, locale="en_US")
+
+
+@pytest.mark.all_locales
+def test_no_inherit_metazone_marker_never_in_output(locale):
+    # See: https://github.com/python-babel/babel/issues/428
+    tz = pytz.timezone('America/Los_Angeles')
+    t = tz.localize(datetime(2016, 1, 6, 7))
+    assert NO_INHERITANCE_MARKER not in dates.format_time(t, format='long', locale=locale)
+    assert NO_INHERITANCE_MARKER not in dates.get_timezone_name(t, width='short', locale=locale)
+
+
+def test_no_inherit_metazone_formatting():
+    # See: https://github.com/python-babel/babel/issues/428
+    tz = pytz.timezone('America/Los_Angeles')
+    t = tz.localize(datetime(2016, 1, 6, 7))
+    assert dates.format_time(t, format='long', locale='en_US') == "7:00:00 AM PST"
+    assert dates.format_time(t, format='long', locale='en_GB') == "07:00:00 Pacific Standard Time"
+    assert dates.get_timezone_name(t, width='short', locale='en_US') == "PST"
+    assert dates.get_timezone_name(t, width='short', locale='en_GB') == "Pacific Standard Time"