Adapt loader_criteria params for current query

Fixed critical issue in the new :meth:`_orm.PropComparator.and_` feature
where loader strategies that emit secondary SELECT statements such as
:func:`_orm.selectinload` and :func:`_orm.lazyload` would fail to
accommodate for bound parameters in the user-defined criteria in terms of
the current statement being executed, as opposed to the cached statement,
causing stale bound values to be used.

This also adds a warning for the case where an object that uses
:func:`_orm.lazyload` in conjunction with :meth:`_orm.PropComparator.and_`
is attempted to be serialized; the loader criteria cannot reliably
be serialized and deserialized and eager loading should be used for this
case.

Fixes: #6139
Change-Id: I5a638bbecb7b583db2d3c0b76469f5a25c13dd3b

1 files changed, 8 insertions, 0 deletions

diff --git a/lib/sqlalchemy/sql/traversals.py b/lib/sqlalchemy/sql/traversals.py
index 3849749de..f2099f191 100644
--- a/lib/sqlalchemy/sql/traversals.py
+++ b/lib/sqlalchemy/sql/traversals.py
@@ -378,6 +378,14 @@ class CacheKey(namedtuple("CacheKey", ["key", "bindparams"])):
         _anon_map = prefix_anon_map()
         return {b.key % _anon_map: b.effective_value for b in self.bindparams}
 
+    def _apply_params_to_element(self, original_cache_key, target_element):
+        translate = {
+            k.key: v.value
+            for k, v in zip(original_cache_key.bindparams, self.bindparams)
+        }
+
+        return target_element.params(translate)
+
 
 def _clone(element, **kw):
     return element._clone()