Commit 91f701f4 authored by Markus Holtermann's avatar Markus Holtermann
Browse files

Fixed #25280 -- Properly checked regex objects for equality to prevent infinite migrations 

Thanks Sayid Munawar and Tim Graham for the report, investigation and
review.
parent 11750276

django/db/migrations/autodetector.py

+3 −0
Original line number Diff line number Diff line
@@ -11,6 +11,7 @@ from django.db.migrations.migration import Migration 
from django.db.migrations.operations.models import AlterModelOptions

from django.db.migrations.optimizer import MigrationOptimizer

from django.db.migrations.questioner import MigrationQuestioner

from django.db.migrations.utils import COMPILED_REGEX_TYPE, RegexObject

from django.utils import six



from .topological_sort import stable_topological_sort
@@ -62,6 +63,8 @@ class MigrationAutodetector(object): 
                key: self.deep_deconstruct(value)

                for key, value in obj.items()

            }

        elif isinstance(obj, COMPILED_REGEX_TYPE):

            return RegexObject(obj)

        elif isinstance(obj, type):

            # If this is a type that implements 'deconstruct' as an instance method,

            # avoid treating this as being deconstructible itself - see #22951

django/db/migrations/utils.py

0 → 100644
+12 −0
Original line number Diff line number Diff line 
import re



COMPILED_REGEX_TYPE = type(re.compile(''))





class RegexObject(object):

    def __init__(self, obj):

        self.pattern = obj.pattern

        self.flags = obj.flags



    def __eq__(self, other):

        return self.pattern == other.pattern and self.flags == other.flags

django/db/migrations/writer.py

+2 −3
Original line number Diff line number Diff line
@@ -14,6 +14,7 @@ from django.apps import apps 
from django.db import migrations, models

from django.db.migrations.loader import MigrationLoader

from django.db.migrations.operations.base import Operation

from django.db.migrations.utils import COMPILED_REGEX_TYPE, RegexObject

from django.utils import datetime_safe, six

from django.utils._os import upath

from django.utils.encoding import force_text
@@ -23,8 +24,6 @@ from django.utils.module_loading import module_dir 
from django.utils.timezone import utc

from django.utils.version import get_docs_version



COMPILED_REGEX_TYPE = type(re.compile(''))





class SettingsReference(str):

    """
@@ -506,7 +505,7 @@ class MigrationWriter(object): 
            format = "(%s)" if len(strings) != 1 else "(%s,)"

            return format % (", ".join(strings)), imports

        # Compiled regex

        elif isinstance(value, COMPILED_REGEX_TYPE):

        elif isinstance(value, (COMPILED_REGEX_TYPE, RegexObject)):

            imports = {"import re"}

            regex_pattern, pattern_imports = cls.serialize(value.pattern)

            regex_flags, flag_imports = cls.serialize(value.flags)

tests/migrations/test_autodetector.py

+43 −0
Original line number Diff line number Diff line 
# -*- coding: utf-8 -*-

import re



from django.conf import settings

from django.contrib.auth.models import AbstractBaseUser

from django.core.validators import RegexValidator, validate_slug

from django.db import connection, models

from django.db.migrations.autodetector import MigrationAutodetector

from django.db.migrations.graph import MigrationGraph
@@ -997,6 +1000,46 @@ class AutodetectorTests(TestCase): 
        self.assertOperationAttributes(changes, "testapp", 0, 0, old_name="Author", new_name="NewAuthor")

        self.assertOperationAttributes(changes, "testapp", 0, 1, name="newauthor", table="author_three")



    def test_identical_regex_doesnt_alter(self):

        from_state = ModelState(

            "testapp", "model", [("id", models.AutoField(primary_key=True, validators=[

                RegexValidator(

                    re.compile('^[-a-zA-Z0-9_]+\\Z'),

                    "Enter a valid 'slug' consisting of letters, numbers, underscores or hyphens.",

                    'invalid'

                )

            ]))]

        )

        to_state = ModelState(

            "testapp", "model", [("id", models.AutoField(primary_key=True, validators=[validate_slug]))]

        )

        before = self.make_project_state([from_state])

        after = self.make_project_state([to_state])

        autodetector = MigrationAutodetector(before, after)

        changes = autodetector._detect_changes()

        # Right number/type of migrations?

        self.assertNumberMigrations(changes, "testapp", 0)



    def test_different_regex_does_alter(self):

        from_state = ModelState(

            "testapp", "model", [("id", models.AutoField(primary_key=True, validators=[

                RegexValidator(

                    re.compile('^[a-z]+\\Z', 32),

                    "Enter a valid 'slug' consisting of letters, numbers, underscores or hyphens.",

                    'invalid'

                )

            ]))]

        )

        to_state = ModelState(

            "testapp", "model", [("id", models.AutoField(primary_key=True, validators=[validate_slug]))]

        )

        before = self.make_project_state([from_state])

        after = self.make_project_state([to_state])

        autodetector = MigrationAutodetector(before, after)

        changes = autodetector._detect_changes()

        self.assertNumberMigrations(changes, "testapp", 1)

        self.assertOperationTypes(changes, "testapp", 0, ["AlterField"])



    def test_empty_foo_together(self):

        """

        #23452 - Empty unique/index_together shouldn't generate a migration.