Fix byte-length validation for memoryviews

stone/backends/python_rsrc/stone_validators.py

@@ -370,12 +370,13 @@ def validate(self, val):
         if not isinstance(val, _binary_types):
             raise ValidationError("expected bytes type, got %s"
                                   % generic_type_name(val))
-        elif self.max_length is not None and len(val) > self.max_length:
+        length = val.nbytes if isinstance(val, memoryview) else len(val)
+        if self.max_length is not None and length > self.max_length:
             raise ValidationError("'%s' must have at most %d bytes, got %d"
-                                  % (get_value_string(val), self.max_length, len(val)))
-        elif self.min_length is not None and len(val) < self.min_length:
+                                  % (get_value_string(val), self.max_length, length))
+        elif self.min_length is not None and length < self.min_length:
             raise ValidationError("'%s' has fewer than %d bytes, got %d"
-                                  % (get_value_string(val), self.min_length, len(val)))
+                                  % (get_value_string(val), self.min_length, length))
         return val
 
 

test/test_python_gen.py

@@ -117,6 +117,16 @@ def test_bytes_validator(self):
         # Passes
         b.validate(b'\x00')
 
+    def test_bytes_validator_memoryview_length(self):
+        value = memoryview(b'abcdefgh').cast('I')
+        self.assertIs(bv.Bytes(min_length=8, max_length=8).validate(value), value)
+        with self.assertRaisesRegex(bv.ValidationError, 'at most 7 bytes, got 8'):
+            bv.Bytes(max_length=7).validate(value)
+
+    def test_bytes_validator_multidimensional_memoryview(self):
+        value = memoryview(b'abcdefgh').cast('B', shape=[2, 4])
+        self.assertIs(bv.Bytes(min_length=8, max_length=8).validate(value), value)
+
     def test_timestamp_validator(self):
         class UTC(datetime.tzinfo):
             def utcoffset(self, dt):  # pylint: disable=unused-argument,useless-suppression