From 42af2e01269ab442970d2fa1d9e9f4fc044dd408 Mon Sep 17 00:00:00 2001
From: Lars Kruse <devel@sumpfralle.de>
Date: Tue, 26 Oct 2021 22:34:45 +0200
Subject: [PATCH] Handle queryset implementations without lhs/rhs attribute
 (#204)

The `ExtraJoinRestriction` class used by django-taggit lacks the
attributes "rhs" and "lhs".
Thus projects cannot use django-taggit together with cachalot.

Closes: #121
---
 cachalot/utils.py | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/cachalot/utils.py b/cachalot/utils.py
index da5f2e4..f228701 100644
--- a/cachalot/utils.py
+++ b/cachalot/utils.py
@@ -135,10 +135,15 @@ def _find_subqueries_in_where(children):
         elif child_class is NothingNode:
             pass
         else:
-            rhs = _find_rhs_lhs_subquery(child.rhs)
+            try:
+                child_rhs = child.rhs
+                child_lhs = child.lhs
+            except AttributeError:
+                raise UncachableQuery
+            rhs = _find_rhs_lhs_subquery(child_rhs)
             if rhs is not None:
                 yield rhs
-            lhs = _find_rhs_lhs_subquery(child.lhs)
+            lhs = _find_rhs_lhs_subquery(child_lhs)
             if lhs is not None:
                 yield lhs