KiCost variants: empty DNF fields shouldn't be excluded.

Fixes #101

CHANGELOG.md

@@ -41,6 +41,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - `--list`: problems with layers and fields specific for the project.
   (INTI-CMNB/kibot_variants_arduprog#4)
 - Makefile: %VALUE not expanded in the directory targets.
+- KiCost variants: empty DNF fields shouldn't be excluded. (#101)
 
 
 ## [0.11.0] - 2021-04-25

kibot/fil_base.py

@@ -284,8 +284,9 @@ class BaseFilter(RegFilter):
         o_tree = {'name': name}
         o_tree['type'] = 'generic'
         o_tree['comment'] = 'Internal filter for KiCost `dnp` field'
-        # dnp = 0 is included, other dnp values are excluded
-        o_tree['exclude_any'] = [{'column': 'dnp', 'regex': r'^\s*0(\.0*)?\s*$', 'invert': True, 'skip_if_no_field': True}]
+        # dnp = 0 and empty are included, other dnp values are excluded
+        o_tree['exclude_any'] = [{'column': 'dnp', 'regex': r'^((\s*0(\.0*)?\s*)|(\s*))$', 'invert': True,
+                                  'skip_if_no_field': True}]
         return o_tree
 
     @staticmethod