Use related_name for MTO queries (#123)

Author: Archmonger

CHANGELOG.md

@@ -22,7 +22,9 @@ Using the following categories, list your changes in this order:
 
 ## [Unreleased]
 
--   Nothing (yet)
+### Fixed
+
+-   `use_query` will now utilize `field.related_name` when postprocessing many-to-one relationships
 
 ## [2.2.1] - 2022-01-09
 

pyproject.toml

@@ -10,6 +10,7 @@ ensure_newline_before_comments = "True"
 include_trailing_comma = "True"
 line_length = 88
 lines_after_imports = 2
+extend_skip_glob = ["*/migrations/*"]
 
 [tool.mypy]
 ignore_missing_imports = true

src/django_idom/utils.py

@@ -232,7 +232,7 @@ def django_query_postprocessor(
                 getattr(data, field.name)
 
             if many_to_one and type(field) == ManyToOneRel:
-                prefetch_fields.append(f"{field.name}_set")
+                prefetch_fields.append(field.related_name or f"{field.name}_set")
 
             elif many_to_many and isinstance(field, ManyToManyField):
                 prefetch_fields.append(field.name)

tests/test_app/components.py

@@ -199,7 +199,7 @@ def relational_query():
 
     mtm = relational_parent.data.many_to_many.all()
     oto = relational_parent.data.one_to_one
-    mto = relational_parent.data.foriegnchild_set.all()
+    mto = relational_parent.data.many_to_one.all()
     fk = foriegn_child.data.parent
 
     return html.div(

tests/test_app/migrations/0003_alter_foriegnchild_parent_and_more.py

@@ -0,0 +1,33 @@
+# Generated by Django 4.1.5 on 2023-01-13 23:23
+
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("test_app", "0002_relationalchild_relationalparent_foriegnchild"),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name="foriegnchild",
+            name="parent",
+            field=models.ForeignKey(
+                on_delete=django.db.models.deletion.CASCADE,
+                related_name="parent",
+                to="test_app.relationalparent",
+            ),
+        ),
+        migrations.AlterField(
+            model_name="relationalparent",
+            name="one_to_one",
+            field=models.OneToOneField(
+                null=True,
+                on_delete=django.db.models.deletion.SET_NULL,
+                related_name="one_to_one",
+                to="test_app.relationalchild",
+            ),
+        ),
+    ]

tests/test_app/migrations/0004_alter_foriegnchild_parent.py

@@ -0,0 +1,23 @@
+# Generated by Django 4.1.5 on 2023-01-13 23:28
+
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("test_app", "0003_alter_foriegnchild_parent_and_more"),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name="foriegnchild",
+            name="parent",
+            field=models.ForeignKey(
+                on_delete=django.db.models.deletion.CASCADE,
+                related_name="foriegn_child",
+                to="test_app.relationalparent",
+            ),
+        ),
+    ]

tests/test_app/migrations/0005_alter_foriegnchild_parent.py

@@ -0,0 +1,23 @@
+# Generated by Django 4.1.5 on 2023-01-13 23:38
+
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("test_app", "0004_alter_foriegnchild_parent"),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name="foriegnchild",
+            name="parent",
+            field=models.ForeignKey(
+                on_delete=django.db.models.deletion.CASCADE,
+                related_name="many_to_one",
+                to="test_app.relationalparent",
+            ),
+        ),
+    ]

tests/test_app/models.py

@@ -20,4 +20,4 @@ class RelationalParent(models.Model):
 
 class ForiegnChild(models.Model):
     text = models.CharField(max_length=1000)  # type: ignore
-    parent = models.ForeignKey(RelationalParent, on_delete=models.CASCADE)  # type: ignore
+    parent = models.ForeignKey(RelationalParent, related_name="many_to_one", on_delete=models.CASCADE)  # type: ignore

tests/test_app/tests/test_components.py

@@ -16,7 +16,7 @@ def setUpClass(cls):
             asyncio.set_event_loop_policy(asyncio.WindowsProactorEventLoopPolicy())
 
         # FIXME: This is required otherwise the tests will throw a `SynchronousOnlyOperation`
-        # error when deleting the test datatabase. Potentially a Django bug.
+        # error when discarding the test datatabase. Potentially a `ChannelsLiveServerTestCase` bug.
         os.environ["DJANGO_ALLOW_ASYNC_UNSAFE"] = "true"
 
         super().setUpClass()