Fixed #31233 -- Closed database connections and cursors after use.

8 files changed, 28 insertions, 16 deletions

diff --git a/django/db/backends/mysql/base.py b/django/db/backends/mysql/base.py
index 527197971f..be00024849 100644
--- a/django/db/backends/mysql/base.py
+++ b/django/db/backends/mysql/base.py
@@ -269,7 +269,8 @@ class DatabaseWrapper(BaseDatabaseWrapper):
         forward references. Always return True to indicate constraint checks
         need to be re-enabled.
         """
-        self.cursor().execute('SET foreign_key_checks=0')
+        with self.cursor() as cursor:
+            cursor.execute('SET foreign_key_checks=0')
         return True
 
     def enable_constraint_checking(self):
@@ -280,7 +281,8 @@ class DatabaseWrapper(BaseDatabaseWrapper):
         # nested inside transaction.atomic.
         self.needs_rollback, needs_rollback = False, self.needs_rollback
         try:
-            self.cursor().execute('SET foreign_key_checks=1')
+            with self.cursor() as cursor:
+                cursor.execute('SET foreign_key_checks=1')
         finally:
             self.needs_rollback = needs_rollback
 
diff --git a/django/db/backends/oracle/base.py b/django/db/backends/oracle/base.py
index e303ec1f3d..652e323521 100644
--- a/django/db/backends/oracle/base.py
+++ b/django/db/backends/oracle/base.py
@@ -301,8 +301,9 @@ class DatabaseWrapper(BaseDatabaseWrapper):
         Check constraints by setting them to immediate. Return them to deferred
         afterward.
         """
-        self.cursor().execute('SET CONSTRAINTS ALL IMMEDIATE')
-        self.cursor().execute('SET CONSTRAINTS ALL DEFERRED')
+        with self.cursor() as cursor:
+            cursor.execute('SET CONSTRAINTS ALL IMMEDIATE')
+            cursor.execute('SET CONSTRAINTS ALL DEFERRED')
 
     def is_usable(self):
         try:
diff --git a/django/db/backends/postgresql/base.py b/django/db/backends/postgresql/base.py
index 0f45ca93e1..192316d7fb 100644
--- a/django/db/backends/postgresql/base.py
+++ b/django/db/backends/postgresql/base.py
@@ -277,13 +277,15 @@ class DatabaseWrapper(BaseDatabaseWrapper):
         Check constraints by setting them to immediate. Return them to deferred
         afterward.
         """
-        self.cursor().execute('SET CONSTRAINTS ALL IMMEDIATE')
-        self.cursor().execute('SET CONSTRAINTS ALL DEFERRED')
+        with self.cursor() as cursor:
+            cursor.execute('SET CONSTRAINTS ALL IMMEDIATE')
+            cursor.execute('SET CONSTRAINTS ALL DEFERRED')
 
     def is_usable(self):
         try:
             # Use a psycopg cursor directly, bypassing Django's utilities.
-            self.connection.cursor().execute("SELECT 1")
+            with self.connection.cursor() as cursor:
+                cursor.execute('SELECT 1')
         except Database.Error:
             return False
         else:
diff --git a/django/db/backends/sqlite3/base.py b/django/db/backends/sqlite3/base.py
index 642d3d6c5a..7b3f90a2fd 100644
--- a/django/db/backends/sqlite3/base.py
+++ b/django/db/backends/sqlite3/base.py
@@ -296,7 +296,8 @@ class DatabaseWrapper(BaseDatabaseWrapper):
         return not bool(enabled)
 
     def enable_constraint_checking(self):
-        self.cursor().execute('PRAGMA foreign_keys = ON')
+        with self.cursor() as cursor:
+            cursor.execute('PRAGMA foreign_keys = ON')
 
     def check_constraints(self, table_names=None):
         """
@@ -309,7 +310,7 @@ class DatabaseWrapper(BaseDatabaseWrapper):
         if self.features.supports_pragma_foreign_key_check:
             with self.cursor() as cursor:
                 if table_names is None:
-                    violations = self.cursor().execute('PRAGMA foreign_key_check').fetchall()
+                    violations = cursor.execute('PRAGMA foreign_key_check').fetchall()
                 else:
                     violations = chain.from_iterable(
                         cursor.execute('PRAGMA foreign_key_check(%s)' % table_name).fetchall()
diff --git a/django/db/migrations/executor.py b/django/db/migrations/executor.py
index 1f65a7fe99..2765ac28bd 100644
--- a/django/db/migrations/executor.py
+++ b/django/db/migrations/executor.py
@@ -372,10 +372,8 @@ class MigrationExecutor:
                     else:
                         found_add_field_migration = True
                         continue
-                columns = self.connection.introspection.get_table_description(
-                    self.connection.cursor(),
-                    table,
-                )
+                with self.connection.cursor() as cursor:
+                    columns = self.connection.introspection.get_table_description(cursor, table)
                 for column in columns:
                     field_column = field.column
                     column_name = column.name
diff --git a/django/db/migrations/recorder.py b/django/db/migrations/recorder.py
index b8e32a468c..1a37c6b7d0 100644
--- a/django/db/migrations/recorder.py
+++ b/django/db/migrations/recorder.py
@@ -52,7 +52,9 @@ class MigrationRecorder:
 
     def has_table(self):
         """Return True if the django_migrations table exists."""
-        return self.Migration._meta.db_table in self.connection.introspection.table_names(self.connection.cursor())
+        with self.connection.cursor() as cursor:
+            tables = self.connection.introspection.table_names(cursor)
+        return self.Migration._meta.db_table in tables
 
     def ensure_schema(self):
         """Ensure the table exists and has the correct schema."""
diff --git a/django/db/models/query.py b/django/db/models/query.py
index 74be5df0ac..a7c16c4bd8 100644
--- a/django/db/models/query.py
+++ b/django/db/models/query.py
@@ -747,7 +747,10 @@ class QuerySet:
         query = self.query.clone()
         query.__class__ = sql.DeleteQuery
         cursor = query.get_compiler(using).execute_sql(CURSOR)
-        return cursor.rowcount if cursor else 0
+        if cursor:
+            with cursor:
+                return cursor.rowcount
+        return 0
     _raw_delete.alters_data = True
 
     def update(self, **kwargs):
diff --git a/django/db/models/sql/subqueries.py b/django/db/models/sql/subqueries.py
index af48239cdc..72b6712864 100644
--- a/django/db/models/sql/subqueries.py
+++ b/django/db/models/sql/subqueries.py
@@ -21,7 +21,10 @@ class DeleteQuery(Query):
         self.alias_map = {table: self.alias_map[table]}
         self.where = where
         cursor = self.get_compiler(using).execute_sql(CURSOR)
-        return cursor.rowcount if cursor else 0
+        if cursor:
+            with cursor:
+                return cursor.rowcount
+        return 0
 
     def delete_batch(self, pk_list, using):
         """