- Fixed unexpected-use regression where in the odd case that the

primaryjoin of a relationship involved comparison to an unhashable
type such as an HSTORE, lazy loads would fail due to a hash-oriented
check on the statement parameters, modified in 1.0 as a result of
:ticket:`3061` to use hashing and modified in :ticket:`3368`
to occur in cases more common than "load on pending".
The values are now checked for the ``__hash__`` attribute beforehand.
fixes #3416

2 files changed, 14 insertions, 1 deletions

diff --git a/lib/sqlalchemy/util/__init__.py b/lib/sqlalchemy/util/__init__.py
index d777d2e06..ed968f168 100644
--- a/lib/sqlalchemy/util/__init__.py
+++ b/lib/sqlalchemy/util/__init__.py
@@ -19,7 +19,7 @@ from ._collections import KeyedTuple, ImmutableContainer, immutabledict, \
     OrderedSet, IdentitySet, OrderedIdentitySet, column_set, \
     column_dict, ordered_column_set, populate_column_dict, unique_list, \
     UniqueAppender, PopulateDict, EMPTY_SET, to_list, to_set, \
-    to_column_set, update_copy, flatten_iterator, \
+    to_column_set, update_copy, flatten_iterator, has_intersection, \
     LRUCache, ScopedRegistry, ThreadLocalRegistry, WeakSequence, \
     coerce_generator_arg, lightweight_named_tuple
 
diff --git a/lib/sqlalchemy/util/_collections.py b/lib/sqlalchemy/util/_collections.py
index db2c21949..5c62ebed8 100644
--- a/lib/sqlalchemy/util/_collections.py
+++ b/lib/sqlalchemy/util/_collections.py
@@ -800,6 +800,19 @@ def to_list(x, default=None):
         return list(x)
 
 
+def has_intersection(set_, iterable):
+    """return True if any items of set_ are present in iterable.
+
+    Goes through special effort to ensure __hash__ is not called
+    on items in iterable that don't support it.
+
+    """
+    # TODO: optimize, write in C, etc.
+    return bool(
+        set_.intersection([i for i in iterable if i.__hash__])
+    )
+
+
 def to_set(x):
     if x is None:
         return set()