Review

Doc/library/gettext.rst

@@ -131,8 +131,8 @@ install themselves in the built-in namespace as the function :func:`!_`.
 
    If *localedir* is not given, then the default system locale directory is used.
    [#]_  If *languages* is not given, then the environment variable :envvar:`LANGUAGE`
-   is searched, it falls back to :func:`locale.setlocale`, which in turn falls
-   back to the environment variables :envvar:`LC_ALL`, :envvar:`LC_MESSAGES`, and
+   is searched, it falls back to the current locale or to the environment
+   variables :envvar:`LC_ALL`, :envvar:`LC_MESSAGES`, and
    :envvar:`LANG` where the first one returning a non-empty value is used for the
    *languages* variable. The environment variables should contain a colon separated
    list of languages, which will be split on the colon to produce the expected list

Lib/gettext.py

@@ -493,8 +493,8 @@ def find(domain, localedir=None, languages=None, all=False):
         languages = []
         if val := os.environ.get('LANGUAGE'):
             languages = val.split(':')
-        elif (loc := locale.setlocale(locale.LC_MESSAGES)) != (None, None):
-            languages = [".".join(filter(None, loc))]
+        elif loc := locale.setlocale(locale.LC_MESSAGES):
+            languages = loc.split(':')
         else:
             for envar in ('LC_ALL', 'LC_MESSAGES', 'LANG'):
                 val = os.environ.get(envar)

Lib/test/test_gettext.py

@@ -1,3 +1,6 @@
+import sys
+
+import locale
 import os
 import base64
 import gettext
@@ -6,8 +9,7 @@
 from functools import partial
 
 from test import support
-from test.support import os_helper
-
+from test.support import os_helper, run_with_locale
 
 # TODO:
 #  - Add new tests, for example for "dgettext"
@@ -736,32 +738,63 @@ def create_mo_file(self, lang):
             f.write(GNU_MO_DATA)
         return mo_file
 
-    def _for_all_vars(self, mo_file, locale):
+    def _for_all_vars(self, mo_file, locale, expected=True):
         for var in ('LANGUAGE', 'LC_ALL', 'LC_MESSAGES', 'LANG'):
             self.env.set(var, locale)
             result = gettext.find("mofile",
                                   localedir=os.path.join(self.tempdir, "locale"))
-            self.assertEqual(mo_file, result)
+            if expected:
+                self.assertEqual(mo_file, result)
+            else:
+                self.assertIsNone(result)
             self.env.unset(var)
 
-    @unittest.mock.patch("locale.setlocale", return_value=(None, None))
+    @unittest.mock.patch("locale.setlocale", return_value='')
     def test_find_with_env_vars(self, patch_getlocale):
         # test that find correctly finds the environment variables
         # when languages are not supplied
+        mo_file = self.create_mo_file("ca_ES")
+        self._for_all_vars(mo_file, "ca_ES")
+        self._for_all_vars(mo_file, "ca_ES.UTF-8")
+        self._for_all_vars(mo_file, "ca_ES.UTF-8.mo")
+        self._for_all_vars(mo_file, "es_ES:ca_ES:fr_FR")
+        self._for_all_vars(mo_file, "ca_ES@euro")
+        self._for_all_vars(mo_file, "ca_ES.UTF-8@euro")
+        self._for_all_vars(mo_file, "ca_ES@valencia")
+        self._for_all_vars(mo_file, "C", expected=False)
+        self._for_all_vars(mo_file, "C.UTF-8", expected=False)
+
+    @unittest.mock.patch('gettext._expand_lang')
+    def test_encoding_not_ignored(self, patch_expand_lang):
+        self.env.set('LANGUAGE', 'ga_IE.UTF-8')
+        gettext.find("mofile")
+        patch_expand_lang.assert_any_call('ga_IE.UTF-8')
+        self.env.unset('LANGUAGE')
+
+    def test_find_LANGUAGE_priority(self):
+        orig = locale.setlocale(locale.LC_MESSAGES)
+        self.addCleanup(lambda: locale.setlocale(locale.LC_MESSAGES, orig))
+        self.env.set('LANGUAGE', 'ga_IE')
+        self.env.set('LC_ALL', 'pt_BR')
+        locale.setlocale(locale.LC_MESSAGES, 'pt_BR')
         mo_file = self.create_mo_file("ga_IE")
-        self._for_all_vars(mo_file, "ga_IE")
-        self._for_all_vars(mo_file, "ga_IE.UTF-8")
-        self._for_all_vars(mo_file, "es_ES:ga_IE:fr_FR")
-        self._for_all_vars(mo_file, "ga_IE@euro")
+
+        result = gettext.find("mofile", localedir=os.path.join(self.tempdir, "locale"))
+        self.assertEqual(result, mo_file)
+        locale.setlocale(locale.LC_MESSAGES, orig)
 
     def test_process_vars_override(self):
-        mo_file = self.create_mo_file("ga_IE")
-        with unittest.mock.patch("locale.setlocale", return_value=('ga_IE', 'UTF-8')):
+        orig = locale.setlocale(locale.LC_MESSAGES)
+        self.addCleanup(lambda: locale.setlocale(locale.LC_MESSAGES, orig))
+        mo_file = self.create_mo_file("ca_ES")
+        for loc in ("ca_ES", "ca_ES.UTF-8", "ca_ES@euro", "ca_ES@valencia"):
+            locale.setlocale(locale.LC_MESSAGES, loc)
             result = gettext.find("mofile", localedir=os.path.join(self.tempdir, "locale"))
             self.assertEqual(mo_file, result)
-        with unittest.mock.patch("locale.setlocale", return_value=('ga_IE', None)):
+        for loc in ("C", "C.UTF-8"):
+            locale.setlocale(locale.LC_MESSAGES, loc)
             result = gettext.find("mofile", localedir=os.path.join(self.tempdir, "locale"))
-            self.assertEqual(mo_file, result)
+            self.assertIsNone(result)
 
     def test_find_with_languages(self):
         # test that passed languages are used