[5.0.x] Refs #34380 -- Added FORMS_URLFIELD_ASSUME_HTTPS transitional setting.

This allows early adoption of the new default "https".

Backport of a4931cd75a from main.

django/conf/__init__.py

@@ -16,7 +16,7 @@ from pathlib import Path
 import django
 from django.conf import global_settings
 from django.core.exceptions import ImproperlyConfigured
-from django.utils.deprecation import RemovedInDjango51Warning
+from django.utils.deprecation import RemovedInDjango51Warning, RemovedInDjango60Warning
 from django.utils.functional import LazyObject, empty
 
 ENVIRONMENT_VARIABLE = "DJANGO_SETTINGS_MODULE"
@@ -31,6 +31,11 @@ STATICFILES_STORAGE_DEPRECATED_MSG = (
     "The STATICFILES_STORAGE setting is deprecated. Use STORAGES instead."
 )
 
+# RemovedInDjango60Warning.
+FORMS_URLFIELD_ASSUME_HTTPS_DEPRECATED_MSG = (
+    "The FORMS_URLFIELD_ASSUME_HTTPS transitional setting is deprecated."
+)
+
 
 class SettingsReference(str):
     """
@@ -205,6 +210,12 @@ class Settings:
                 setattr(self, setting, setting_value)
                 self._explicit_settings.add(setting)
 
+        if self.is_overridden("FORMS_URLFIELD_ASSUME_HTTPS"):
+            warnings.warn(
+                FORMS_URLFIELD_ASSUME_HTTPS_DEPRECATED_MSG,
+                RemovedInDjango60Warning,
+            )
+
         if hasattr(time, "tzset") and self.TIME_ZONE:
             # When we can, attempt to validate the timezone. If we can't find
             # this file, no check happens and it's harmless.
@@ -293,6 +304,11 @@ class UserSettingsHolder:
                 "BACKEND": self.STATICFILES_STORAGE
             }
             warnings.warn(STATICFILES_STORAGE_DEPRECATED_MSG, RemovedInDjango51Warning)
+        if name == "FORMS_URLFIELD_ASSUME_HTTPS":
+            warnings.warn(
+                FORMS_URLFIELD_ASSUME_HTTPS_DEPRECATED_MSG,
+                RemovedInDjango60Warning,
+            )
         super().__setattr__(name, value)
         # RemovedInDjango51Warning.
         if name == "STORAGES":

django/conf/global_settings.py

@@ -216,6 +216,11 @@ TEMPLATES = []
 # Default form rendering class.
 FORM_RENDERER = "django.forms.renderers.DjangoTemplates"
 
+# RemovedInDjango60Warning: It's a transitional setting helpful in early
+# adoption of "https" as the new default value of forms.URLField.assume_scheme.
+# Set to True to assume "https" during the Django 5.x release cycle.
+FORMS_URLFIELD_ASSUME_HTTPS = False
+
 # Default email address to use for various automated correspondence from
 # the site managers.
 DEFAULT_FROM_EMAIL = "webmaster@localhost"

django/forms/fields.py

@@ -15,6 +15,7 @@ from decimal import Decimal, DecimalException
 from io import BytesIO
 from urllib.parse import urlsplit, urlunsplit
 
+from django.conf import settings
 from django.core import validators
 from django.core.exceptions import ValidationError
 from django.forms.boundfield import BoundField
@@ -762,14 +763,19 @@ class URLField(CharField):
 
     def __init__(self, *, assume_scheme=None, **kwargs):
         if assume_scheme is None:
-            warnings.warn(
+            if settings.FORMS_URLFIELD_ASSUME_HTTPS:
-                "The default scheme will be changed from 'http' to 'https' in Django "
+                assume_scheme = "https"
-                "6.0. Pass the forms.URLField.assume_scheme argument to silence this "
+            else:
-                "warning.",
+                warnings.warn(
-                RemovedInDjango60Warning,
+                    "The default scheme will be changed from 'http' to 'https' in "
-                stacklevel=2,
+                    "Django 6.0. Pass the forms.URLField.assume_scheme argument to "
-            )
+                    "silence this warning, or set the FORMS_URLFIELD_ASSUME_HTTPS "
-            assume_scheme = "http"
+                    "transitional setting to True to opt into using 'https' as the new "
+                    "default scheme.",
+                    RemovedInDjango60Warning,
+                    stacklevel=2,
+                )
+                assume_scheme = "http"
         # RemovedInDjango60Warning: When the deprecation ends, replace with:
         # self.assume_scheme = assume_scheme or "https"
         self.assume_scheme = assume_scheme

docs/internals/deprecation.txt

@@ -53,6 +53,8 @@ details on these changes.
 * ``get_prefetcher()`` and ``prefetch_related_objects()`` will no longer
   fallback to ``get_prefetch_queryset()``.
 
+* The ``FORMS_URLFIELD_ASSUME_HTTPS`` transitional setting will be removed.
+
 .. _deprecation-removed-in-5.1:
 
 5.1

docs/ref/forms/fields.txt

@@ -1154,7 +1154,9 @@ For each field, we describe the default widget used if you don't specify
     .. deprecated:: 5.0
 
         The default value for ``assume_scheme`` will change from ``"http"`` to
-        ``"https"`` in Django 6.0.
+        ``"https"`` in Django 6.0. Set :setting:`FORMS_URLFIELD_ASSUME_HTTPS`
+        transitional setting to ``True`` to opt into using ``"https"`` during
+        the Django 5.x release cycle.
 
 ``UUIDField``
 -------------

docs/ref/settings.txt

@@ -1693,6 +1693,20 @@ renderers are:
 * ``'``:class:`django.forms.renderers.Jinja2`\ ``'``
 * ``'``:class:`django.forms.renderers.TemplatesSetting`\ ``'``
 
+.. setting:: FORMS_URLFIELD_ASSUME_HTTPS
+
+``FORMS_URLFIELD_ASSUME_HTTPS``
+-------------------------------
+
+.. versionadded:: 5.0
+.. deprecated:: 5.0
+
+Default: ``False``
+
+Set this transitional setting to ``True`` to opt into using ``"https"`` as the
+new default value of :attr:`URLField.assume_scheme
+<django.forms.URLField.assume_scheme>` during the Django 5.x release cycle.
+
 .. setting:: FORMAT_MODULE_PATH
 
 ``FORMAT_MODULE_PATH``
@@ -3677,6 +3691,7 @@ File uploads
 Forms
 -----
 * :setting:`FORM_RENDERER`
+* :setting:`FORMS_URLFIELD_ASSUME_HTTPS`
 
 Globalization (``i18n``/``l10n``)
 ---------------------------------

docs/releases/5.0.txt

@@ -612,7 +612,11 @@ Miscellaneous
 * The ``ForeignObject.get_reverse_joining_columns()`` method is deprecated.
 
 * The default scheme for ``forms.URLField`` will change from ``"http"`` to
-  ``"https"`` in Django 6.0.
+  ``"https"`` in Django 6.0. Set :setting:`FORMS_URLFIELD_ASSUME_HTTPS`
+  transitional setting to ``True`` to opt into assuming ``"https"`` during the
+  Django 5.x release cycle.
+
+* ``FORMS_URLFIELD_ASSUME_HTTPS`` transitional setting is deprecated.
 
 * Support for calling ``format_html()`` without passing args or kwargs will be
   removed.

tests/forms_tests/field_tests/test_urlfield.py

@@ -1,3 +1,7 @@
+import sys
+from types import ModuleType
+
+from django.conf import FORMS_URLFIELD_ASSUME_HTTPS_DEPRECATED_MSG, Settings, settings
 from django.core.exceptions import ValidationError
 from django.forms import URLField
 from django.test import SimpleTestCase, ignore_warnings
@@ -155,8 +159,41 @@ class URLFieldAssumeSchemeDeprecationTest(FormFieldAssertionsMixin, SimpleTestCa
     def test_urlfield_raises_warning(self):
         msg = (
             "The default scheme will be changed from 'http' to 'https' in Django 6.0. "
-            "Pass the forms.URLField.assume_scheme argument to silence this warning."
+            "Pass the forms.URLField.assume_scheme argument to silence this warning, "
+            "or set the FORMS_URLFIELD_ASSUME_HTTPS transitional setting to True to "
+            "opt into using 'https' as the new default scheme."
         )
         with self.assertWarnsMessage(RemovedInDjango60Warning, msg):
             f = URLField()
             self.assertEqual(f.clean("example.com"), "http://example.com")
+
+    @ignore_warnings(category=RemovedInDjango60Warning)
+    def test_urlfield_forms_urlfield_assume_https(self):
+        with self.settings(FORMS_URLFIELD_ASSUME_HTTPS=True):
+            f = URLField()
+            self.assertEqual(f.clean("example.com"), "https://example.com")
+            f = URLField(assume_scheme="http")
+            self.assertEqual(f.clean("example.com"), "http://example.com")
+
+    def test_override_forms_urlfield_assume_https_setting_warning(self):
+        msg = FORMS_URLFIELD_ASSUME_HTTPS_DEPRECATED_MSG
+        with self.assertRaisesMessage(RemovedInDjango60Warning, msg):
+            # Changing FORMS_URLFIELD_ASSUME_HTTPS via self.settings() raises a
+            # deprecation warning.
+            with self.settings(FORMS_URLFIELD_ASSUME_HTTPS=True):
+                pass
+
+    def test_settings_init_forms_urlfield_assume_https_warning(self):
+        settings_module = ModuleType("fake_settings_module")
+        settings_module.FORMS_URLFIELD_ASSUME_HTTPS = True
+        sys.modules["fake_settings_module"] = settings_module
+        msg = FORMS_URLFIELD_ASSUME_HTTPS_DEPRECATED_MSG
+        try:
+            with self.assertRaisesMessage(RemovedInDjango60Warning, msg):
+                Settings("fake_settings_module")
+        finally:
+            del sys.modules["fake_settings_module"]
+
+    def test_access_forms_urlfield_assume_https(self):
+        # Warning is not raised on access.
+        self.assertEqual(settings.FORMS_URLFIELD_ASSUME_HTTPS, False)

tests/model_forms/tests.py

@@ -2929,7 +2929,8 @@ class ModelOtherFieldTests(SimpleTestCase):
         msg = (
             "The default scheme will be changed from 'http' to 'https' in Django "
             "6.0. Pass the forms.URLField.assume_scheme argument to silence this "
-            "warning."
+            "warning, or set the FORMS_URLFIELD_ASSUME_HTTPS transitional setting to "
+            "True to opt into using 'https' as the new default scheme."
         )
         with self.assertWarnsMessage(RemovedInDjango60Warning, msg):
 
@@ -2938,6 +2939,18 @@ class ModelOtherFieldTests(SimpleTestCase):
                     model = Homepage
                     fields = "__all__"
 
+    def test_url_modelform_assume_scheme_early_adopt_https(self):
+        msg = "The FORMS_URLFIELD_ASSUME_HTTPS transitional setting is deprecated."
+        with (
+            self.assertWarnsMessage(RemovedInDjango60Warning, msg),
+            self.settings(FORMS_URLFIELD_ASSUME_HTTPS=True),
+        ):
+
+            class HomepageForm(forms.ModelForm):
+                class Meta:
+                    model = Homepage
+                    fields = "__all__"
+
     def test_modelform_non_editable_field(self):
         """
         When explicitly including a non-editable field in a ModelForm, the