Parameters object is not pickle-able

[hdoupe]

For some reason, marshmallow Schemas are not pickle-able if type is used to generate them:

Works just fine:

class Schema1(ma.Schema):
    a = ma.fields.Str()

schema1 = Schema1()
pickle.dump(schema1, open("schema1.pickle", "wb"))

Breaks:

Schema2 = type(
    "Schema2",
    (ma.Schema, ),
    {"a": ma.fields.Str()}
)

schema2 = Schema2()
pickle.dump(schema2, open("schema2.pickle", "wb"))


# ---------------------------------------------------------------------------
# PicklingError                             Traceback (most recent call last)
# <ipython-input-3-3309ac14ecbf> in <module>
#       6 
#       7 schema2 = Schema2()
# ----> 8 pickle.dump(schema2, open("schema2.pickle", "wb"))

# PicklingError: Can't pickle <class 'marshmallow.schema.Schema2'>: attribute lookup Schema2 on marshmallow.schema failed

Thanks for the bug report @jdebacker.

[jdebacker]

Solution to this problem seems to be to use cloudpickle, which can save dynamic class objects.