Fixed getting default encoding in get_system_username

Refs #19933.

django/contrib/auth/management/__init__.py

@@ -12,6 +12,7 @@ from django.core import exceptions
 from django.core.management.base import CommandError
 from django.db import DEFAULT_DB_ALIAS, router
 from django.db.models import get_models, signals
+from django.utils.encoding import DEFAULT_LOCALE_ENCODING
 from django.utils import six
 from django.utils.six.moves import input
 
@@ -133,11 +134,8 @@ def get_system_username():
         # (a very restricted chroot environment, for example).
         return ''
     if not six.PY3:
-        default_locale = locale.getdefaultlocale()[1]
-        if not default_locale:
-            return ''
         try:
-            result = result.decode(default_locale)
+            result = result.decode(DEFAULT_LOCALE_ENCODING)
         except UnicodeDecodeError:
             # UnicodeDecodeError - preventive treatment for non-latin Windows.
             return ''

django/utils/encoding.py

@@ -236,11 +236,17 @@ def filepath_to_uri(path):
     # some flexibility for hardcoding separators.
     return quote(force_bytes(path.replace("\\", "/")), safe=b"/~!*()'")
 
-# The encoding of the default system locale but falls back to the
-# given fallback encoding if the encoding is unsupported by python or could
-# not be determined.  See tickets #10335 and #5846
-try:
-    DEFAULT_LOCALE_ENCODING = locale.getdefaultlocale()[1] or 'ascii'
-    codecs.lookup(DEFAULT_LOCALE_ENCODING)
-except:
-    DEFAULT_LOCALE_ENCODING = 'ascii'
+def get_system_encoding():
+    """
+    The encoding of the default system locale but falls back to the given
+    fallback encoding if the encoding is unsupported by python or could
+    not be determined.  See tickets #10335 and #5846
+    """
+    try:
+        encoding = locale.getdefaultlocale()[1] or 'ascii'
+        codecs.lookup(encoding)
+    except Exception:
+        encoding = 'ascii'
+    return encoding
+
+DEFAULT_LOCALE_ENCODING = get_system_encoding()