Commit 80e3444e authored by David Szotten's avatar David Szotten Committed by Tim Graham
Browse files

Fixed #24483 -- Prevented keepdb from breaking with generator choices. 

If Field.choices is provided as an iterator, consume it in __init__ instead
of using itertools.tee (which ends up holding everything in memory
anyway). Fixes a bug where deconstruct() was consuming the iterator but
bypassing the call to `tee`.
parent 118cae2d

django/db/models/fields/__init__.py

+4 −12
Original line number Diff line number Diff line
@@ -9,7 +9,6 @@ import math 
import uuid

import warnings

from base64 import b64decode, b64encode

from itertools import tee



from django.apps import apps

from django.db import connection
@@ -155,7 +154,9 @@ class Field(RegisterLookupMixin): 
        self.unique_for_date = unique_for_date

        self.unique_for_month = unique_for_month

        self.unique_for_year = unique_for_year

        self._choices = choices or []

        if isinstance(choices, collections.Iterator):

            choices = list(choices)

        self.choices = choices or []

        self.help_text = help_text

        self.db_index = db_index

        self.db_column = db_column
@@ -405,7 +406,6 @@ class Field(RegisterLookupMixin): 
        }

        attr_overrides = {

            "unique": "_unique",

            "choices": "_choices",

            "error_messages": "_error_messages",

            "validators": "_validators",

            "verbose_name": "_verbose_name",
@@ -553,7 +553,7 @@ class Field(RegisterLookupMixin): 
            # Skip validation for non-editable fields.

            return



        if self._choices and value not in self.empty_values:

        if self.choices and value not in self.empty_values:

            for option_key, option_value in self.choices:

                if isinstance(option_value, (list, tuple)):

                    # This is an optgroup, so look inside the group for
@@ -848,14 +848,6 @@ class Field(RegisterLookupMixin): 
        """

        return smart_text(self._get_val_from_obj(obj))



    def _get_choices(self):

        if isinstance(self._choices, collections.Iterator):

            choices, self._choices = tee(self._choices)

            return choices

        else:

            return self._choices

    choices = property(_get_choices)



    def _get_flatchoices(self):

        """Flattened version of choices tuple."""

        flat = []

tests/migrations/test_state.py

+20 −0
Original line number Diff line number Diff line
@@ -595,6 +595,26 @@ class StateTests(TestCase): 
        self.assertIsNot(old_model.food_mgr.model, new_model.food_mgr.model)

        self.assertIsNot(old_model.food_qs.model, new_model.food_qs.model)



    def test_choices_iterator(self):

        """

        #24483 - ProjectState.from_apps should not destructively consume

        Field.choices iterators.

        """

        new_apps = Apps(["migrations"])

        choices = [('a', 'A'), ('b', 'B')]



        class Author(models.Model):

            name = models.CharField(max_length=255)

            choice = models.CharField(max_length=255, choices=iter(choices))



            class Meta:

                app_label = "migrations"

                apps = new_apps



        ProjectState.from_apps(new_apps)

        choices_field = Author._meta.get_field('choice')

        self.assertEqual(list(choices_field.choices), choices)





class ModelStateTests(TestCase):

    def test_custom_model_base(self):

tests/model_fields/tests.py

+0 −7
Original line number Diff line number Diff line
@@ -445,13 +445,6 @@ class ChoicesTests(test.TestCase): 
        self.assertEqual(WhizIterEmpty(c=None).c, None)    # Blank value

        self.assertEqual(WhizIterEmpty(c='').c, '')        # Empty value



    def test_charfield_get_choices_with_blank_iterator(self):

        """

        Check that get_choices works with an empty Iterator

        """

        f = models.CharField(choices=(x for x in []))

        self.assertEqual(f.get_choices(include_blank=True), [('', '---------')])





class SlugFieldTests(test.TestCase):

    def test_slugfield_max_length(self):