Revert 3.2.9: "Refactor tracing implementation"

[bonjourmauko]

Bug fix

Fixes #899
Fixes openfisca/openfisca-france#1360

Note: Versions 3.2.9 and 3.3.0 have been unpublished as the
former accidentally introduced a bug affecting the Web API. Please use
version 3.3.1 or more recent.

• Revert version 3.2.9 as it introduced a bug that rendered the Web
  API unusable
  • In this version, the tracer outputs numpy.ndarray as a valid
    value for parameters
  • Since numpy.ndarray is not JSON serializable, the Web API crashes
    when trying to serialize a trace

How to reprode the error

You can use the following snippet:

from flask import Flask, jsonify
from openfisca_core.scripts import build_tax_benefit_system
from openfisca_web_api.loader import build_data

def trace():
    tax_benefit_system = build_tax_benefit_system("openfisca_france", None, None)
    data = build_data(tax_benefit_system)
    return data["openAPI_spec"]["definitions"]["Trace"]["example"]["trace"]

def acc(data, key):
    params = data[key]["parameters"]
    return [(key, param, params[param], type(params[param])) for param in params.keys()]

def serializable(value):
    try:
        jsonify({**value})
        return True
    except TypeError:
        return False

with Flask(__name__).app_context():
    data = trace()
    result = [acc(data, key) for key, _ in data.items() if not serializable(data[key])]

Expected

result
>>> []

Actual

result[0][0]
(
  'aide_logement_loyer_plafond<2017-12>',
  'prestations.aides_logement.loyers_plafond.par_zone<2017-12-01>',
  array([51.54]),
  numpy.ndarray),
  )

[fpagnoux]

Darn, this should have been caught by tests 🤦‍♂. Thanks for catching that.

Rather than reverting and re-reverting, I'd suggest:

• Unpublish corrupt versions
• Work on a fix
• Publish fix

I think it'd we less work and cleaner. I can work on the fix right now.

[bonjourmauko]

Thanks @fpagnoux. I tried unpublishing with openfisca-bot, but the ”manage” button was greyed-out.

[fpagnoux]

Alternative fix without revert here: #900.
It solves the issue locally, but an extra check would be safer 🙂