From 7d3405c18770081b7e73636b1f080eab5fe61d08 Mon Sep 17 00:00:00 2001
From: Theodor Franke <theodor.franke@outlook.de>
Date: Tue, 24 Sep 2024 19:34:41 +0200
Subject: [PATCH] Add support for GeneratedFields

---
 django_filters/filterset.py | 14 ++++++++++++++
 tests/models.py             | 19 +++++++++++++++++++
 tests/test_filterset.py     | 23 +++++++++++++++++------
 3 files changed, 50 insertions(+), 6 deletions(-)

diff --git a/django_filters/filterset.py b/django_filters/filterset.py
index 23a88b45c..415c8a7ac 100644
--- a/django_filters/filterset.py
+++ b/django_filters/filterset.py
@@ -29,6 +29,13 @@
 )
 from .utils import get_all_model_fields, get_model_field, resolve_field, try_dbfield
 
+try:
+    from django.db.models import GeneratedField
+except ImportError:
+    DJANGO_50 = False
+else:
+    DJANGO_50 = True
+
 
 def remote_queryset(field):
     """
@@ -390,6 +397,13 @@ def handle_unrecognized_field(cls, field_name, message):
     def filter_for_field(cls, field, field_name, lookup_expr=None):
         if lookup_expr is None:
             lookup_expr = settings.DEFAULT_LOOKUP_EXPR
+
+        # Handle GeneratedFields
+        if DJANGO_50 and isinstance(field, GeneratedField):
+            new_field = field.output_field
+            new_field.model = field.model
+            field = new_field
+
         field, lookup_type = resolve_field(field, lookup_expr)
 
         default = {
diff --git a/tests/models.py b/tests/models.py
index e1a391b21..319ee8f8e 100644
--- a/tests/models.py
+++ b/tests/models.py
@@ -1,7 +1,15 @@
 from django import forms
 from django.db import models
+from django.db.models import F
 from django.utils.translation import gettext_lazy as _
 
+try:
+    from django.db.models import GeneratedField
+except ImportError:
+    DJANGO_50 = False
+else:
+    DJANGO_50 = True
+
 REGULAR = 0
 MANAGER = 1
 ADMIN = 2
@@ -210,3 +218,14 @@ class SpacewalkRecord(models.Model):
 
     astronaut = models.CharField(max_length=100)
     duration = models.DurationField()
+
+
+if DJANGO_50:
+    class Rectangle(models.Model):
+        base = models.FloatField()
+        height = models.FloatField()
+        area = GeneratedField(
+            expression=F("base") * F("height"),
+            output_field=models.FloatField(),
+            db_persist=True,
+        )
diff --git a/tests/test_filterset.py b/tests/test_filterset.py
index 77fafee51..c3fd63440 100644
--- a/tests/test_filterset.py
+++ b/tests/test_filterset.py
@@ -49,6 +49,13 @@
 )
 from .utils import MockQuerySet
 
+try:
+    from .models import Rectangle
+except ImportError:
+    DJANGO_50 = False
+else:
+    DJANGO_50 = True
+
 
 class HelperMethodsTests(TestCase):
     @unittest.skip("todo")
@@ -119,6 +126,14 @@ def test_filter_found_for_uuidfield(self):
         self.assertIsInstance(result, UUIDFilter)
         self.assertEqual(result.field_name, "uuid")
 
+    def test_filter_found_for_generatedfield(self):
+        if not DJANGO_50:
+            return
+        f = Rectangle._meta.get_field("area")
+        result = FilterSet.filter_for_field(f, "area")
+        self.assertIsInstance(result, NumberFilter)
+        self.assertEqual(result.field_name, "area")
+
     def test_filter_found_for_autofield(self):
         f = User._meta.get_field("id")
         result = FilterSet.filter_for_field(f, "id")
@@ -256,7 +271,6 @@ def test_unknown_field_ignore_behavior(self):
     def test_unknown_field_invalid_initial_behavior(self):
         # Creation of new custom FilterSet to set initial field behavior
         with self.assertRaises(ValueError) as excinfo:
-
             class InvalidBehaviorFilterSet(FilterSet):
                 class Meta:
                     model = NetworkSetting
@@ -421,7 +435,6 @@ class Meta:
 
     def test_model_no_fields_or_exclude(self):
         with self.assertRaises(AssertionError) as excinfo:
-
             class F(FilterSet):
                 class Meta:
                     model = Book
@@ -548,7 +561,6 @@ def test_meta_fields_list_containing_unknown_fields(self):
         msg = "'Meta.fields' must not contain non-model field names: " "other, another"
 
         with self.assertRaisesMessage(TypeError, msg):
-
             class F(FilterSet):
                 username = CharFilter()
 
@@ -560,7 +572,6 @@ def test_meta_fields_dict_containing_unknown_fields(self):
         msg = "'Meta.fields' must not contain non-model field names: other"
 
         with self.assertRaisesMessage(TypeError, msg):
-
             class F(FilterSet):
                 class Meta:
                     model = Book
@@ -575,7 +586,6 @@ def test_meta_fields_dict_containing_declarative_alias(self):
         msg = "'Meta.fields' must not contain non-model field names: other"
 
         with self.assertRaisesMessage(TypeError, msg):
-
             class F(FilterSet):
                 other = CharFilter()
 
@@ -593,7 +603,6 @@ def test_meta_fields_invalid_lookup(self):
         msg = "Unsupported lookup 'flub' for field 'tests.User.username'."
 
         with self.assertRaisesMessage(FieldLookupError, msg):
-
             class F(FilterSet):
                 class Meta:
                     model = User
@@ -822,6 +831,7 @@ def test_filterset_factory_base_filter_meta_fields(self):
         class FilterSetBase(FilterSet):
             class Meta:
                 fields = ["name"]
+
             f1 = CharFilter()
             f2 = CharFilter()
 
@@ -832,6 +842,7 @@ def test_filterset_factory_base_filter_fields_and_meta_fields(self):
         class FilterSetBase(FilterSet):
             class Meta:
                 fields = ["name"]
+
             f1 = CharFilter()
             f2 = CharFilter()