Fixed #29817 -- Deprecated settings.FILE_CHARSET.

1 files changed, 25 insertions, 1 deletions

diff --git a/django/conf/__init__.py b/django/conf/__init__.py
index a380806485..73d943d26e 100644
--- a/django/conf/__init__.py
+++ b/django/conf/__init__.py
@@ -16,12 +16,18 @@ from pathlib import Path
 import django
 from django.conf import global_settings
 from django.core.exceptions import ImproperlyConfigured
-from django.utils.deprecation import RemovedInDjango30Warning
+from django.utils.deprecation import (
+    RemovedInDjango30Warning, RemovedInDjango31Warning,
+)
 from django.utils.functional import LazyObject, empty
 
 ENVIRONMENT_VARIABLE = "DJANGO_SETTINGS_MODULE"
 
 DEFAULT_CONTENT_TYPE_DEPRECATED_MSG = 'The DEFAULT_CONTENT_TYPE setting is deprecated.'
+FILE_CHARSET_DEPRECATED_MSG = (
+    'The FILE_CHARSET setting is deprecated. Starting with Django 3.1, all '
+    'files read from disk must be UTF-8 encoded.'
+)
 
 
 class LazySettings(LazyObject):
@@ -111,6 +117,20 @@ class LazySettings(LazyObject):
             )
         return self.__getattr__('DEFAULT_CONTENT_TYPE')
 
+    @property
+    def FILE_CHARSET(self):
+        stack = traceback.extract_stack()
+        # Show a warning if the setting is used outside of Django.
+        # Stack index: -1 this line, -2 the caller.
+        filename, _line_number, _function_name, _text = stack[-2]
+        if not filename.startswith(os.path.dirname(django.__file__)):
+            warnings.warn(
+                FILE_CHARSET_DEPRECATED_MSG,
+                RemovedInDjango31Warning,
+                stacklevel=2,
+            )
+        return self.__getattr__('FILE_CHARSET')
+
 
 class Settings:
     def __init__(self, settings_module):
@@ -145,6 +165,8 @@ class Settings:
 
         if self.is_overridden('DEFAULT_CONTENT_TYPE'):
             warnings.warn(DEFAULT_CONTENT_TYPE_DEPRECATED_MSG, RemovedInDjango30Warning)
+        if self.is_overridden('FILE_CHARSET'):
+            warnings.warn(FILE_CHARSET_DEPRECATED_MSG, RemovedInDjango31Warning)
 
         if hasattr(time, 'tzset') and self.TIME_ZONE:
             # When we can, attempt to validate the timezone. If we can't find
@@ -191,6 +213,8 @@ class UserSettingsHolder:
         self._deleted.discard(name)
         if name == 'DEFAULT_CONTENT_TYPE':
             warnings.warn(DEFAULT_CONTENT_TYPE_DEPRECATED_MSG, RemovedInDjango30Warning)
+        elif name == 'FILE_CHARSET':
+            warnings.warn(FILE_CHARSET_DEPRECATED_MSG, RemovedInDjango31Warning)
         super().__setattr__(name, value)
 
     def __delattr__(self, name):