Allow array indices / lookup nodes to be used as dict keys.

Fixes #2158

peewee.py

@@ -6237,8 +6237,10 @@ def _normalize_data(cls, data, kwargs):
                     field = (key if isinstance(key, Field)
                              else cls._meta.combined[key])
                 except KeyError:
-                    raise ValueError('Unrecognized field name: "%s" in %s.' %
-                                     (key, data))
+                    if not isinstance(key, Node):
+                        raise ValueError('Unrecognized field name: "%s" in %s.'
+                                         % (key, data))
+                    field = key
                 normalized[field] = data[key]
         if kwargs:
             for key in kwargs:

playhouse/postgres_ext.py

@@ -62,6 +62,9 @@ def __init__(self, node, parts):
     def clone(self):
         return type(self)(self.node, list(self.parts))
 
+    def __hash__(self):
+        return hash((self.__class__.__name__, id(self)))
+
 
 class _JsonLookupBase(_LookupNode):
     def __init__(self, node, parts, as_json=False):

tests/postgres.py

@@ -306,6 +306,18 @@ def test_index_expression(self):
         q = ArrayModel.select().where(ArrayModel.tags[last_tag] > 'd')
         self.assertEqual([a.id for a in q], [am_ids[1]])
 
+    def test_hashable_objectslice(self):
+        ArrayModel.create(tags=[], ints=[[0, 1], [2, 3]])
+        ArrayModel.create(tags=[], ints=[[4, 5], [6, 7]])
+        n = (ArrayModel
+             .update({ArrayModel.ints[0][0]: ArrayModel.ints[0][0] + 1})
+             .execute())
+        self.assertEqual(n, 2)
+
+        am1, am2 = ArrayModel.select().order_by(ArrayModel.id)
+        self.assertEqual(am1.ints, [[1, 1], [2, 3]])
+        self.assertEqual(am2.ints, [[5, 5], [6, 7]])
+
     def test_array_get_set(self):
         am = self.create_sample()
         am_db = ArrayModel.get(ArrayModel.id == am.id)