Fixed #10197 -- Corrected pickling of querysets when a subset of fields was selected.

        obj_dict['related_select_fields'] = []

        obj_dict['related_select_cols'] = []

        del obj_dict['connection']

        # Fields can't be pickled, so we pickle the list of field names instead.

        obj_dict['select_fields'] = [f.name for f in obj_dict['select_fields']]

        return obj_dict

    def __setstate__(self, obj_dict):

        """

        Unpickling support.

        """

        # Rebuild list of field instances

        obj_dict['select_fields'] = [obj_dict['model']._meta.get_field(name) for name in obj_dict['select_fields']]

        self.__dict__.update(obj_dict)

        # XXX: Need a better solution for this when multi-db stuff is

        # supported. It's the only class-reference to the module-level

# coding: utf-8

import pickle

from django.db import models

from django.conf import settings

>>> Book.objects.filter(id__in=ids)

[<Book: Python Web Development with Django>]

# Regression for #10197 -- Queries with aggregates can be pickled.

# First check that pickling is possible at all. No crash = success

>>> qs = Book.objects.annotate(num_authors=Count('authors'))

>>> out = pickle.dumps(qs)

# Then check that the round trip works.

>>> query = qs.query.as_sql()[0]

>>> select_fields = qs.query.select_fields

>>> query2 = pickle.loads(pickle.dumps(qs))

>>> query2.query.as_sql()[0] == query

True

>>> query2.query.select_fields = select_fields

# Regression for #10199 - Aggregate calls clone the original query so the original query can still be used

>>> books = Book.objects.all()

>>> _ = books.aggregate(Avg('authors__age'))