bugfix: Fix an occasional compatibility issue when using Excel formulas

tests/test_formulas.py

@@ -79,3 +79,12 @@ def test_if(self):
 
     def test_choose(self):
         self.assertEqual(self.get_value(1, 6), "'C'")
+
+    def test_evaluate_name_formula_with_invalid_operand(self):
+        book = xlrd.open_workbook(from_sample('invalid_formula.xls'))
+        sheet = book.sheet_by_index(0)
+        cell = sheet.cell(0, 0)
+
+        self.assertEqual(cell.ctype, xlrd.XL_CELL_ERROR)
+        self.assertIn(cell.value, xlrd.error_text_from_code)
+

xlrd/formula.py

@@ -953,7 +953,7 @@ def not_in_name_formula(op_arg, oname_arg):
                 ])
                 res = Operand(oREF, None, rank, otext)
                 if bop.kind == oERR or aop.kind == oERR:
-                    res = oERR
+                    res.kind = oERR
                 elif bop.kind == oREF == aop.kind:
                     if aop.value is not None and bop.value is not None:
                         assert len(aop.value) == 1