Initial

Doc/library/gettext.rst

@@ -130,9 +130,10 @@ install themselves in the built-in namespace as the function :func:`!_`.
    strings, where each string is a language code.
 
    If *localedir* is not given, then the default system locale directory is used.
-   [#]_  If *languages* is not given, then the following environment variables are
-   searched: :envvar:`LANGUAGE`, :envvar:`LC_ALL`, :envvar:`LC_MESSAGES`, and
-   :envvar:`LANG`.  The first one returning a non-empty value is used for the
+   [#]_  If *languages* is not given, then the environment variable :envvar:`LANGUAGE`
+   is searched, it falls back to :func:`locale.getlocale`, which in turn falls
+   back 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
    of language code strings.
@@ -147,6 +148,9 @@ install themselves in the built-in namespace as the function :func:`!_`.
    of all file names, in the order in which they appear in the languages list or
    the environment variables.
 
+   .. versionchanged:: next
+      :func:`locale.getlocale` is used to generate *languages* if *languages* is
+      not provided.
 
 .. function:: translation(domain, localedir=None, languages=None, class_=None, fallback=False)
 

Lib/gettext.py

@@ -46,6 +46,7 @@
 import operator
 import os
 import sys
+import locale
 
 
 __all__ = ['NullTranslations', 'GNUTranslations', 'Catalog',
@@ -491,11 +492,16 @@ def find(domain, localedir=None, languages=None, all=False):
         localedir = _default_localedir
     if languages is None:
         languages = []
-        for envar in ('LANGUAGE', 'LC_ALL', 'LC_MESSAGES', 'LANG'):
-            val = os.environ.get(envar)
-            if val:
-                languages = val.split(':')
-                break
+        if os.environ.get('LANGUAGE'):
+            languages = os.environ.get('LANGUAGE').split(',')
+        elif locale.getlocale() != (None, None):
+            languages.append(".".join(filter(None, locale.getlocale())))
+        else:
+            for envar in ('LC_ALL', 'LC_MESSAGES', 'LANG'):
+                val = os.environ.get(envar)
+                if val:
+                    languages = val.split(':')
+                    break
         if 'C' not in languages:
             languages.append('C')
     # now normalize and expand the languages

Lib/test/test_gettext.py

@@ -1,3 +1,4 @@
+import locale
 import os
 import base64
 import gettext
@@ -736,7 +737,8 @@ def create_mo_file(self, lang):
             f.write(GNU_MO_DATA)
         return mo_file
 
-    def test_find_with_env_vars(self):
+    @unittest.mock.patch("locale.getlocale", return_value=(None, None))
+    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("ga_IE")
@@ -747,6 +749,12 @@ def test_find_with_env_vars(self):
             self.assertEqual(result, mo_file)
             self.env.unset(var)
 
+    @unittest.mock.patch("locale.getlocale", return_value=('ga_IE', 'UTF-8'))
+    def test_process_vars_override(self, patch_getlocale):
+        mo_file = self.create_mo_file("ga_IE")
+        result = gettext.find("mofile", localedir=os.path.join(self.tempdir, "locale"))
+        self.assertEqual(result, mo_file)
+
     def test_find_with_languages(self):
         # test that passed languages are used
         self.env.set('LANGUAGE', 'pt_BR')

Misc/NEWS.d/next/Library/2025-03-19-17-30-00.gh-issue-64243.fuheq3.rst

@@ -0,0 +1,2 @@
+Implement a fall back to :func:`locale.getlocale` in :func:`gettext.find` if
+*languages* is not provided and :envvar:`LANGUAGES` is not set.