[5.2.x] Fixed #36358 -- Corrected introspection of composite primary keys on SQLite.

Previously, any first field of a composite primary key with type
`INTEGER` was incorrectly introspected as an `AutoField` due to SQLite
treating `INTEGER PRIMARY KEY` as an alias for the `ROWID`.

This change ensures that integer fields in composite PKs are not
mistaken for auto-incrementing fields.

Thanks Jacob Walls and Sarah Boyce for the reviews.

Backport of 07100db6f46255ec6ef70b860495f977473684d6 from main.

django/db/backends/sqlite3/introspection.py

@@ -115,7 +115,7 @@ class DatabaseIntrospection(BaseDatabaseIntrospection):
                 ).fetchone()
                 if has_json_constraint:
                     json_columns.add(column)
-        return [
+        table_description = [
             FieldInfo(
                 name,
                 data_type,
@@ -126,7 +126,7 @@ class DatabaseIntrospection(BaseDatabaseIntrospection):
                 not notnull,
                 default,
                 collations.get(name),
-                pk == 1,
+                bool(pk),
                 name in json_columns,
             )
             for cid, name, data_type, notnull, default, pk, hidden in table_info
@@ -137,6 +137,15 @@ class DatabaseIntrospection(BaseDatabaseIntrospection):
                 3,  # Stored generated column.
             ]
         ]
+        # If the primary key is composed of multiple columns they should not
+        # be individually marked as pk.
+        primary_key = [
+            index for index, field_info in enumerate(table_description) if field_info.pk
+        ]
+        if len(primary_key) > 1:
+            for index in primary_key:
+                table_description[index] = table_description[index]._replace(pk=False)
+        return table_description
 
     def get_sequences(self, cursor, table_name, table_fields=()):
         pk_col = self.get_primary_key_column(cursor, table_name)

docs/releases/5.2.1.txt

@@ -55,3 +55,7 @@ Bugfixes
 * Fixed a regression in Django 5.2 that caused a crash when using ``update()``
   on a ``QuerySet`` filtered against a related model and including references
   to annotations through ``values()`` (:ticket:`36360`).
+
+* Fixed a bug in composite primary key introspection that caused
+  ``IntegerField`` to be wrongly identified as ``AutoField`` on SQLite
+  (:ticket:`36358`).

tests/inspectdb/tests.py

@@ -628,10 +628,7 @@ class InspectDBTransactionalTests(TransactionTestCase):
 
     def test_composite_primary_key(self):
         out = StringIO()
-        if connection.vendor == "sqlite":
+        field_type = connection.features.introspected_field_types["IntegerField"]
-            field_type = connection.features.introspected_field_types["AutoField"]
-        else:
-            field_type = connection.features.introspected_field_types["IntegerField"]
         call_command("inspectdb", "inspectdb_compositeprimarykeymodel", stdout=out)
         output = out.getvalue()
         self.assertIn(
@@ -639,8 +636,4 @@ class InspectDBTransactionalTests(TransactionTestCase):
             output,
         )
         self.assertIn(f"column_1 = models.{field_type}()", output)
-        self.assertIn(
+        self.assertIn(f"column_2 = models.{field_type}()", output)
-            "column_2 = models.%s()"
-            % connection.features.introspected_field_types["IntegerField"],
-            output,
-        )