dates: return a location without a region when the locale has no name for it

babel/dates.py

@@ -528,10 +528,10 @@ def get_timezone_location(
     territory = get_global('zone_territories').get(zone)
     if territory not in locale.territories:
         territory = 'ZZ'  # invalid/unknown
-    territory_name = locale.territories[territory]
+    territory_name = locale.territories.get(territory)
     if (
         not return_city
-        and territory
+        and territory_name
         and len(get_global('territory_zones').get(territory, [])) == 1
     ):
         return region_format % territory_name
@@ -552,6 +552,10 @@ def get_timezone_location(
 
     if return_city:
         return city_name
+    if territory_name is None:
+        # The locale has no name for the zone's region, not even for the
+        # "unknown region" fallback, so the region is left out.
+        return region_format % city_name
     return region_format % (
         fallback_format
         % {

tests/test_dates.py

@@ -284,6 +284,17 @@ def test_get_timezone_location(timezone_getter):
             'Deutschland (Berlin) (Ortszeit)')
 
 
+def test_get_timezone_location_without_a_region_name(timezone_getter):
+    # Locales without a name for the "unknown region" (CLDR "ZZ") used to
+    # raise a KeyError instead of falling back to the location without region.
+    tz = timezone_getter('America/St_Johns')
+    assert dates.get_timezone_location(tz, locale='aa') == 'St. John’s'
+    assert dates.get_timezone_location(tz, locale='aa', return_city=True) == 'St. John’s'
+    assert dates.get_timezone_name(tz, locale='aa') == 'St. John’s'
+    # Locales that do have a name for it are unchanged.
+    assert dates.get_timezone_location(tz, locale='en') == 'Canada (St. John’s) Time'
+
+
 @pytest.mark.parametrize(
     ('tzname', 'params', 'expected'),
     [