Fixed #21361 -- allowed access self.value() from SimpleListFilter lookup

Reviewed by Chris Medrela.

django/contrib/admin/filters.py

@@ -67,13 +67,13 @@ class SimpleListFilter(ListFilter):
             raise ImproperlyConfigured(
                 "The list filter '%s' does not specify "
                 "a 'parameter_name'." % self.__class__.__name__)
+        if self.parameter_name in params:
+            value = params.pop(self.parameter_name)
+            self.used_parameters[self.parameter_name] = value
         lookup_choices = self.lookups(request, model_admin)
         if lookup_choices is None:
             lookup_choices = ()
         self.lookup_choices = list(lookup_choices)
-        if self.parameter_name in params:
-            value = params.pop(self.parameter_name)
-            self.used_parameters[self.parameter_name] = value
 
     def has_output(self):
         return len(self.lookup_choices) > 0

tests/admin_filters/tests.py

@@ -106,6 +106,17 @@ class DepartmentListFilterLookupWithUnderscoredParameter(DepartmentListFilterLoo
     parameter_name = 'department__whatever'
 
 
+class DepartmentListFilterLookupWithDynamicValue(DecadeListFilterWithTitleAndParameter):
+
+    def lookups(self, request, model_admin):
+        if self.value() == 'the 80s':
+            return (('the 90s', "the 1990's"),)
+        elif self.value() == 'the 90s':
+            return (('the 80s', "the 1980's"),)
+        else:
+            return (('the 80s', "the 1980's"), ('the 90s', "the 1990's"),)
+
+
 class CustomUserAdmin(UserAdmin):
     list_filter = ('books_authored', 'books_contributed')
 
@@ -169,6 +180,10 @@ class DepartmentFilterUnderscoredEmployeeAdmin(EmployeeAdmin):
     list_filter = [DepartmentListFilterLookupWithUnderscoredParameter, ]
 
 
+class DepartmentFilterDynamicValueBookAdmin(EmployeeAdmin):
+    list_filter = [DepartmentListFilterLookupWithDynamicValue, ]
+
+
 class ListFiltersTests(TestCase):
 
     def setUp(self):
@@ -816,3 +831,25 @@ class ListFiltersTests(TestCase):
         self.assertEqual(choices[2]['display'], 'Design')
         self.assertEqual(choices[2]['selected'], False)
         self.assertEqual(choices[2]['query_string'], '?department__code__exact=DSN')
+
+    def test_lookup_with_dynamic_value(self):
+        """
+        Ensure SimpleListFilter can access self.value() inside the lookup.
+        """
+        modeladmin = DepartmentFilterDynamicValueBookAdmin(Book, site)
+
+        def _test_choices(request, expected_displays):
+            changelist = self.get_changelist(request, Book, modeladmin)
+            filterspec = changelist.get_filters(request)[0][0]
+            self.assertEqual(force_text(filterspec.title), 'publication decade')
+            choices = tuple(c['display'] for c in filterspec.choices(changelist))
+            self.assertEqual(choices, expected_displays)
+
+        _test_choices(self.request_factory.get('/', {}),
+                      ("All", "the 1980's", "the 1990's"))
+
+        _test_choices(self.request_factory.get('/', {'publication-decade': 'the 80s'}),
+                      ("All", "the 1990's"))
+
+        _test_choices(self.request_factory.get('/', {'publication-decade': 'the 90s'}),
+                      ("All", "the 1980's"))