Error when trying to encode scalar Enum arrays

[bonjourmauko]

The following code fails for scalar Enum arrays (without dimension):

openfisca-core/openfisca_core/indexed_enums.py

Line 60 in 871bf20

if len(array) > 0 and cls.__name__ is array[0].__class__.__name__:

A real-life example of this bug:

https://github.com/openfisca/openfisca-france/blob/7918eec5be4c2cdeb65da9fb023cfbfcce537156/openfisca_france/model/prestations/logement_social.py#L71-L81

You can reproduce the issue with the following code:

from numpy import array, atleast_1d

from openfisca_core.indexed_enums import Enum

class Greetings(Enum):
    hola = "Hola"
    chao = "Chao"

greeting = array(Greetings.hola)
greeting.size # 1
len(greeting) # TypeError: len() of unsized object
atleast_1d(greeting).size # 1
len(atleast_1d(greeting)) # 1

What's the expected behaviour here?

1. We're expecting an array with at least one dimension.
2. We should make sure we cast or take into account scalar arrays.

cc @Morendil @fpagnoux

[Morendil]

Are you sure? The code in France you are linking to was exercised by France tests and did not seem to be affected by this bug, prior to Core 34.5.4.

(See this comment)

[bonjourmauko]

Not really sure, no : as there it no signature in the original code, I don't know what is the expected behaviour.

So, #923 adds tests assuming we wanted to handle scalar vectors as well.

[bonjourmauko]

So as discussed in openfisca/openfisca-france#1395, it seems the current behaviour is the expected behaviour: expecting a vector.

I'm then :

• Closing this issue for now, do not hesitate to re-open it.
• Adapting feat(entities): add role builder #923 as a test-adding PR, not a bug fix.

Thanks !