Merge pull request #91 from SupImDos/master

Fix `.explain()` in Django >=4.0

Author: millerdev

django_cte/query.py

@@ -82,30 +82,40 @@ def generate_sql(cls, connection, query, as_sql):
             ctes.append(template.format(name=qn(cte.name), query=cte_sql))
             params.extend(cte_params)
 
-        explain_query = getattr(query, "explain_query", None)
-        sql = []
-        if explain_query:
+        # Required due to breaking change in django commit
+        #     fc91ea1e50e5ef207f0f291b3f6c1942b10db7c7
+        if django.VERSION >= (4, 0):
+            explain_attribute = "explain_info"
+            explain_info = getattr(query, explain_attribute, None)
+            explain_format = getattr(explain_info, "format", None)
+            explain_options = getattr(explain_info, "options", {})
+        else:
+            explain_attribute = "explain_query"
             explain_format = getattr(query, "explain_format", None)
             explain_options = getattr(query, "explain_options", {})
+
+        explain_query_or_info = getattr(query, explain_attribute, None)
+        sql = []
+        if explain_query_or_info:
             sql.append(
                 connection.ops.explain_query_prefix(
                     explain_format,
                     **explain_options
                 )
             )
-            # this needs to get set to False so that the base as_sql() doesn't
+            # this needs to get set to None so that the base as_sql() doesn't
             # insert the EXPLAIN statement where it would end up between the
             # WITH ... clause and the final SELECT
-            query.explain_query = False
+            setattr(query, explain_attribute, None)
 
         if ctes:
             # Always use WITH RECURSIVE
             # https://www.postgresql.org/message-id/13122.1339829536%40sss.pgh.pa.us
             sql.extend(["WITH RECURSIVE", ", ".join(ctes)])
         base_sql, base_params = as_sql()
 
-        if explain_query:
-            query.explain_query = explain_query
+        if explain_query_or_info:
+            setattr(query, explain_attribute, explain_query_or_info)
 
         sql.append(base_sql)
         params.extend(base_params)

tests/test_cte.py

@@ -561,8 +561,4 @@ def test_explain(self):
             .order_by("amount")
         )
 
-        # the test db (sqlite3) doesn't support EXPLAIN, so let's just check
-        # to make sure EXPLAIN is at the top
-        orders.query.explain_query = True
-
-        self.assertTrue(str(orders.query).startswith("EXPLAIN "))
+        self.assertIsInstance(orders.explain(), str)