Fixed #30241 -- Added more system checks of translation settings.

3 files changed, 121 insertions, 10 deletions

diff --git a/django/core/checks/translation.py b/django/core/checks/translation.py
index 7ad6d2364c..a385c2d098 100644
--- a/django/core/checks/translation.py
+++ b/django/core/checks/translation.py
@@ -8,6 +8,28 @@ E001 = Error(
     id='translation.E001',
 )
 
+E002 = Error(
+    'You have provided an invalid language code in the LANGUAGES setting: {}.',
+    id='translation.E002',
+)
+
+E003 = Error(
+    'You have provided an invalid language code in the LANGUAGES_BIDI setting: {}.',
+    id='translation.E003',
+)
+
+E004 = Error(
+    'You have provided a value for the LANGUAGE_CODE setting that is not in '
+    'the LANGUAGES setting.',
+    id='translation.E004',
+)
+
+E005 = Error(
+    'You have provided values in the LANGUAGES_BIDI setting that are not in '
+    'the LANGUAGES setting.',
+    id='translation.E005',
+)
+
 
 @register(Tags.translation)
 def check_setting_language_code(app_configs, **kwargs):
@@ -16,3 +38,33 @@ def check_setting_language_code(app_configs, **kwargs):
     if not isinstance(tag, str) or not language_code_re.match(tag):
         return [Error(E001.msg.format(tag), id=E001.id)]
     return []
+
+
+@register(Tags.translation)
+def check_setting_languages(app_configs, **kwargs):
+    """Error if LANGUAGES setting is invalid."""
+    return [
+        Error(E002.msg.format(tag), id=E002.id)
+        for tag, _ in settings.LANGUAGES if not isinstance(tag, str) or not language_code_re.match(tag)
+    ]
+
+
+@register(Tags.translation)
+def check_setting_languages_bidi(app_configs, **kwargs):
+    """Error if LANGUAGES_BIDI setting is invalid."""
+    return [
+        Error(E003.msg.format(tag), id=E003.id)
+        for tag in settings.LANGUAGES_BIDI if not isinstance(tag, str) or not language_code_re.match(tag)
+    ]
+
+
+@register(Tags.translation)
+def check_language_settings_consistent(app_configs, **kwargs):
+    """Error if language settings are not consistent with each other."""
+    available_tags = {i for i, _ in settings.LANGUAGES} | {'en-us'}
+    messages = []
+    if settings.LANGUAGE_CODE not in available_tags:
+        messages.append(E004)
+    if not available_tags.issuperset(settings.LANGUAGES_BIDI):
+        messages.append(E005)
+    return messages
diff --git a/docs/ref/checks.txt b/docs/ref/checks.txt
index 9f2c538fed..84b126bf5f 100644
--- a/docs/ref/checks.txt
+++ b/docs/ref/checks.txt
@@ -441,6 +441,16 @@ The following checks are performed on your translation configuration:
 
 * **translation.E001**: You have provided an invalid value for the
   :setting:`LANGUAGE_CODE` setting: ``<value>``.
+* **translation.E002**: You have provided an invalid language code in the
+  :setting:`LANGUAGES` setting: ``<value>``.
+* **translation.E003**: You have provided an invalid language code in the
+  :setting:`LANGUAGES_BIDI` setting: ``<value>``.
+* **translation.E004**: You have provided a value for the
+  :setting:`LANGUAGE_CODE` setting that is not in the :setting:`LANGUAGES`
+  setting.
+* **translation.E005**: You have provided values in the
+  :setting:`LANGUAGES_BIDI` setting that are not in the :setting:`LANGUAGES`
+  setting.
 
 URLs
 ----
diff --git a/tests/check_framework/test_translation.py b/tests/check_framework/test_translation.py
index 7f6d93b38f..9a34b65c06 100644
--- a/tests/check_framework/test_translation.py
+++ b/tests/check_framework/test_translation.py
@@ -1,12 +1,15 @@
 from django.core.checks import Error
-from django.core.checks.translation import check_setting_language_code
+from django.core.checks.translation import (
+    check_language_settings_consistent, check_setting_language_code,
+    check_setting_languages, check_setting_languages_bidi,
+)
 from django.test import SimpleTestCase
 
 
 class TranslationCheckTests(SimpleTestCase):
 
-    def test_valid_language_code(self):
-        tags = (
+    def setUp(self):
+        self.valid_tags = (
             'en',              # language
             'mas',             # language
             'sgn-ase',         # language+extlang
@@ -17,12 +20,7 @@ class TranslationCheckTests(SimpleTestCase):
             # FIXME: The following should be invalid:
             'sr@latin',        # language+script
         )
-        for tag in tags:
-            with self.subTest(tag), override_settings(LANGUAGE_CODE=tag):
-                self.assertEqual(check_setting_language_code(None), [])
-
-    def test_invalid_language_code(self):
-        tags = (
+        self.invalid_tags = (
             None,              # invalid type: None.
             123,               # invalid type: int.
             b'en',             # invalid type: bytes.
@@ -37,9 +35,60 @@ class TranslationCheckTests(SimpleTestCase):
             # FIXME: The following should be invalid:
             # 'sr@latin',      # locale instead of language tag.
         )
+
+    def test_valid_language_code(self):
+        for tag in self.valid_tags:
+            with self.subTest(tag), self.settings(LANGUAGE_CODE=tag):
+                self.assertEqual(check_setting_language_code(None), [])
+
+    def test_invalid_language_code(self):
         msg = 'You have provided an invalid value for the LANGUAGE_CODE setting: %s.'
-        for tag in tags:
+        for tag in self.invalid_tags:
             with self.subTest(tag), self.settings(LANGUAGE_CODE=tag):
                 self.assertEqual(check_setting_language_code(None), [
                     Error(msg % tag, id='translation.E001'),
                 ])
+
+    def test_valid_languages(self):
+        for tag in self.valid_tags:
+            with self.subTest(tag), self.settings(LANGUAGES=[(tag, tag)]):
+                self.assertEqual(check_setting_languages(None), [])
+
+    def test_invalid_languages(self):
+        msg = 'You have provided an invalid language code in the LANGUAGES setting: %s.'
+        for tag in self.invalid_tags:
+            with self.subTest(tag), self.settings(LANGUAGES=[(tag, tag)]):
+                self.assertEqual(check_setting_languages(None), [
+                    Error(msg % tag, id='translation.E002'),
+                ])
+
+    def test_valid_languages_bidi(self):
+        for tag in self.valid_tags:
+            with self.subTest(tag), self.settings(LANGUAGES_BIDI=[tag]):
+                self.assertEqual(check_setting_languages_bidi(None), [])
+
+    def test_invalid_languages_bidi(self):
+        msg = 'You have provided an invalid language code in the LANGUAGES_BIDI setting: %s.'
+        for tag in self.invalid_tags:
+            with self.subTest(tag), self.settings(LANGUAGES_BIDI=[tag]):
+                self.assertEqual(check_setting_languages_bidi(None), [
+                    Error(msg % tag, id='translation.E003'),
+                ])
+
+    def test_inconsistent_language_settings(self):
+        msg = (
+            'You have provided a value for the LANGUAGE_CODE setting that is '
+            'not in the LANGUAGES setting.'
+        )
+        with self.settings(LANGUAGE_CODE='fr', LANGUAGES=[('en', 'English')], LANGUAGES_BIDI=[]):
+            self.assertEqual(check_language_settings_consistent(None), [
+                Error(msg, id='translation.E004'),
+            ])
+        msg = (
+            'You have provided values in the LANGUAGES_BIDI setting that are '
+            'not in the LANGUAGES setting.'
+        )
+        with self.settings(LANGUAGE_CODE='en', LANGUAGES=[('en', 'English')], LANGUAGES_BIDI=['he']):
+            self.assertEqual(check_language_settings_consistent(None), [
+                Error(msg, id='translation.E005'),
+            ])