Improve usability of Enum values

CHANGELOG.md

@@ -1,5 +1,12 @@
 # Changelog
 
+# 31.0.1 [#840](https://github.com/openfisca/openfisca-core/pull/840)
+
+- Improve usability of Enum values:
+- Details:
+  - Allow the use of Enum values in comparisons: instead of using `<Enum class>.possible_values` you can simply `import` the Enum class
+  - Accept Enum values via set_input (same result as the previous point)
+
 # 31.0.0 [#813](https://github.com/openfisca/openfisca-core/pull/813)
 
 #### Breaking changes

openfisca_core/indexed_enums.py

@@ -50,6 +50,15 @@ def encode(cls, array):
         if array.dtype.kind in {'U', 'S'}:  # String array
             array = np.select([array == item.name for item in cls], [item.index for item in cls]).astype(ENUM_ARRAY_DTYPE)
         elif array.dtype.kind == 'O':  # Enum items arrays
+            # Ensure we are comparing the comparable. The problem this fixes:
+            #  On entering this method "cls" will generally come from variable.possible_values,
+            #  while the array values may come from directly importing a module containing an Enum class.
+            #  However, variables (and hence their possible_values) are loaded by a call to load_module,
+            #  which gives them a different identity from the ones imported in the usual way.
+            #  So, instead of relying on the "cls" passed in, we use only its name to check that
+            #  the values in the array, if non-empty, are of the right type.
+            if len(array) > 0 and cls.__name__ is array[0].__class__.__name__:
+                cls = array[0].__class__
             array = np.select([array == item for item in cls], [item.index for item in cls]).astype(ENUM_ARRAY_DTYPE)
         return EnumArray(array, cls)
 
@@ -75,7 +84,7 @@ def __array_finalize__(self, obj):
 
     def __eq__(self, other):
         # When comparing to an item of self.possible_values, use the item index to speed up the comparison
-        if other.__class__ is self.possible_values:
+        if other.__class__.__name__ is self.possible_values.__name__:
             return self.view(np.ndarray) == other.index  # use view(np.ndarray) so that the result is a classic ndarray, not an EnumArray
         return self.view(np.ndarray) == other
 

openfisca_core/simulations.py

@@ -141,6 +141,8 @@ def calculate(self, variable_name, period, **parameters):
             if array is None:
                 array = holder.default_array()
 
+            array = self._cast_formula_result(array, variable)
+
             holder.put_in_cache(array, period)
         except SpiralError:
             array = holder.default_array()
@@ -248,7 +250,7 @@ def _run_formula(self, variable, entity, period):
             array = formula(entity, period, parameters_at)
 
         self._check_formula_result(array, variable, entity, period)
-        return self._cast_formula_result(array, variable)
+        return array
 
     def _check_period_consistency(self, period, variable):
         """

setup.py

@@ -38,7 +38,7 @@
 
 setup(
     name = 'OpenFisca-Core',
-    version = '31.0.0',
+    version = '31.0.1',
     author = 'OpenFisca Team',
     author_email = 'contact@openfisca.org',
     classifiers = [

tests/core/test_holders.py

@@ -5,6 +5,7 @@
 
 import openfisca_country_template.situation_examples
 from openfisca_core.simulation_builder import SimulationBuilder
+from openfisca_country_template.variables.housing import HousingOccupancyStatus
 from openfisca_core.periods import period as make_period, ETERNITY
 from openfisca_core.tools import assert_near
 from openfisca_core.memory_config import MemoryConfig
@@ -26,7 +27,6 @@ def couple():
 
 
 period = make_period('2017-12')
-HousingOccupancyStatus = tax_benefit_system.get_variable('housing_occupancy_status').possible_values
 
 
 def test_set_input_enum_string(couple):