Fixed #19721 -- Allowed admin filters to customize the list separator.

2 files changed, 4 insertions, 3 deletions

diff --git a/django/contrib/admin/filters.py b/django/contrib/admin/filters.py
index 82dabe4d2c..f6833e57cb 100644
--- a/django/contrib/admin/filters.py
+++ b/django/contrib/admin/filters.py
@@ -118,6 +118,7 @@ class SimpleListFilter(ListFilter):
 class FieldListFilter(ListFilter):
     _field_list_filters = []
     _take_priority_index = 0
+    list_separator = ','
 
     def __init__(self, field, request, params, model, model_admin, field_path):
         self.field = field
@@ -127,7 +128,7 @@ class FieldListFilter(ListFilter):
         for p in self.expected_parameters():
             if p in params:
                 value = params.pop(p)
-                self.used_parameters[p] = prepare_lookup_value(p, value)
+                self.used_parameters[p] = prepare_lookup_value(p, value, self.list_separator)
 
     def has_output(self):
         return True
diff --git a/django/contrib/admin/utils.py b/django/contrib/admin/utils.py
index baaaa9e43f..42d0d96ea6 100644
--- a/django/contrib/admin/utils.py
+++ b/django/contrib/admin/utils.py
@@ -51,13 +51,13 @@ def lookup_spawns_duplicates(opts, lookup_path):
     return False
 
 
-def prepare_lookup_value(key, value):
+def prepare_lookup_value(key, value, separator=','):
     """
     Return a lookup value prepared to be used in queryset filtering.
     """
     # if key ends with __in, split parameter into separate values
     if key.endswith('__in'):
-        value = value.split(',')
+        value = value.split(separator)
     # if key ends with __isnull, special case '' and the string literals 'false' and '0'
     elif key.endswith('__isnull'):
         value = value.lower() not in ('', 'false', '0')