From cb791a2540c289390b68a3ea9c6a79476890bab2 Mon Sep 17 00:00:00 2001
From: Mariusz Felisiak <felisiak.mariusz@gmail.com>
Date: Wed, 3 Aug 2022 11:42:51 +0200
Subject: [PATCH] Fixed #33872 -- Deprecated
 django.contrib.postgres.fields.CIText/CICharField/CIEmailField/CITextField.

---
 django/contrib/postgres/fields/array.py       | 35 ++++++++---
 django/contrib/postgres/fields/citext.py      | 61 +++++++++++++++++-
 django/db/backends/postgresql/operations.py   |  1 +
 docs/internals/deprecation.txt                |  7 +++
 docs/ref/checks.txt                           | 10 +++
 docs/ref/contrib/postgres/fields.txt          | 22 +++++++
 docs/releases/1.11.txt                        |  6 +-
 docs/releases/4.2.txt                         | 14 +++++
 tests/backends/postgresql/tests.py            |  1 +
 .../test_deprecated_fields.py                 | 62 +++++++++++++++++++
 tests/postgres_tests/fields.py                | 12 ++--
 .../migrations/0002_create_test_models.py     |  1 +
 tests/postgres_tests/models.py                |  1 +
 tests/postgres_tests/test_citext.py           |  9 +++
 tests/runtests.py                             |  7 +++
 15 files changed, 228 insertions(+), 21 deletions(-)

diff --git a/django/contrib/postgres/fields/array.py b/django/contrib/postgres/fields/array.py
index 46c3e07b21..3edc72ac94 100644
--- a/django/contrib/postgres/fields/array.py
+++ b/django/contrib/postgres/fields/array.py
@@ -68,18 +68,35 @@ class ArrayField(CheckFieldDefaultMixin, Field):
             )
         else:
             # Remove the field name checks as they are not needed here.
-            base_errors = self.base_field.check()
-            if base_errors:
-                messages = "\n    ".join(
-                    "%s (%s)" % (error.msg, error.id) for error in base_errors
+            base_checks = self.base_field.check()
+            if base_checks:
+                error_messages = "\n    ".join(
+                    "%s (%s)" % (base_check.msg, base_check.id)
+                    for base_check in base_checks
+                    if isinstance(base_check, checks.Error)
                 )
-                errors.append(
-                    checks.Error(
-                        "Base field for array has errors:\n    %s" % messages,
-                        obj=self,
-                        id="postgres.E001",
+                if error_messages:
+                    errors.append(
+                        checks.Error(
+                            "Base field for array has errors:\n    %s" % error_messages,
+                            obj=self,
+                            id="postgres.E001",
+                        )
                     )
+                warning_messages = "\n    ".join(
+                    "%s (%s)" % (base_check.msg, base_check.id)
+                    for base_check in base_checks
+                    if isinstance(base_check, checks.Warning)
                 )
+                if warning_messages:
+                    errors.append(
+                        checks.Warning(
+                            "Base field for array has warnings:\n    %s"
+                            % warning_messages,
+                            obj=self,
+                            id="postgres.W004",
+                        )
+                    )
         return errors
 
     def set_attributes_from_name(self, name):
diff --git a/django/contrib/postgres/fields/citext.py b/django/contrib/postgres/fields/citext.py
index 2b943614d2..2dac2577d1 100644
--- a/django/contrib/postgres/fields/citext.py
+++ b/django/contrib/postgres/fields/citext.py
@@ -1,9 +1,22 @@
+import warnings
+
 from django.db.models import CharField, EmailField, TextField
+from django.test.utils import ignore_warnings
+from django.utils.deprecation import RemovedInDjango51Warning
 
 __all__ = ["CICharField", "CIEmailField", "CIText", "CITextField"]
 
 
+# RemovedInDjango51Warning.
 class CIText:
+    def __init__(self, *args, **kwargs):
+        warnings.warn(
+            "django.contrib.postgres.fields.CIText mixin is deprecated.",
+            RemovedInDjango51Warning,
+            stacklevel=2,
+        )
+        super().__init__(*args, **kwargs)
+
     def get_internal_type(self):
         return "CI" + super().get_internal_type()
 
@@ -12,12 +25,54 @@ class CIText:
 
 
 class CICharField(CIText, CharField):
-    pass
+    system_check_deprecated_details = {
+        "msg": (
+            "django.contrib.postgres.fields.CICharField is deprecated. Support for it "
+            "(except in historical migrations) will be removed in Django 5.1."
+        ),
+        "hint": (
+            'Use CharField(db_collation="…") with a case-insensitive non-deterministic '
+            "collation instead."
+        ),
+        "id": "fields.W905",
+    }
+
+    def __init__(self, *args, **kwargs):
+        with ignore_warnings(category=RemovedInDjango51Warning):
+            super().__init__(*args, **kwargs)
 
 
 class CIEmailField(CIText, EmailField):
-    pass
+    system_check_deprecated_details = {
+        "msg": (
+            "django.contrib.postgres.fields.CIEmailField is deprecated. Support for it "
+            "(except in historical migrations) will be removed in Django 5.1."
+        ),
+        "hint": (
+            'Use EmailField(db_collation="…") with a case-insensitive '
+            "non-deterministic collation instead."
+        ),
+        "id": "fields.W906",
+    }
+
+    def __init__(self, *args, **kwargs):
+        with ignore_warnings(category=RemovedInDjango51Warning):
+            super().__init__(*args, **kwargs)
 
 
 class CITextField(CIText, TextField):
-    pass
+    system_check_deprecated_details = {
+        "msg": (
+            "django.contrib.postgres.fields.CITextField is deprecated. Support for it "
+            "(except in historical migrations) will be removed in Django 5.1."
+        ),
+        "hint": (
+            'Use TextField(db_collation="…") with a case-insensitive non-deterministic '
+            "collation instead."
+        ),
+        "id": "fields.W907",
+    }
+
+    def __init__(self, *args, **kwargs):
+        with ignore_warnings(category=RemovedInDjango51Warning):
+            super().__init__(*args, **kwargs)
diff --git a/django/db/backends/postgresql/operations.py b/django/db/backends/postgresql/operations.py
index e8eb06c9e2..2303703ebc 100644
--- a/django/db/backends/postgresql/operations.py
+++ b/django/db/backends/postgresql/operations.py
@@ -142,6 +142,7 @@ class DatabaseOperations(BaseDatabaseOperations):
         ):
             if internal_type in ("IPAddressField", "GenericIPAddressField"):
                 lookup = "HOST(%s)"
+            # RemovedInDjango51Warning.
             elif internal_type in ("CICharField", "CIEmailField", "CITextField"):
                 lookup = "%s::citext"
             else:
diff --git a/docs/internals/deprecation.txt b/docs/internals/deprecation.txt
index a12834c431..ff10c9de5a 100644
--- a/docs/internals/deprecation.txt
+++ b/docs/internals/deprecation.txt
@@ -25,6 +25,13 @@ details on these changes.
   ``django.contrib.auth.hashers.UnsaltedSHA1PasswordHasher``, and
   ``django.contrib.auth.hashers.UnsaltedMD5PasswordHasher`` will be removed.
 
+* The model ``django.contrib.postgres.fields.CICharField``,
+  ``django.contrib.postgres.fields.CIEmailField``, and
+  ``django.contrib.postgres.fields.CITextField`` will be removed. Stub fields
+  will remain for compatibility with historical migrations.
+
+* The ``django.contrib.postgres.fields.CIText`` mixin will be removed.
+
 .. _deprecation-removed-in-5.0:
 
 5.0
diff --git a/docs/ref/checks.txt b/docs/ref/checks.txt
index 92278db659..aa8d5b6d62 100644
--- a/docs/ref/checks.txt
+++ b/docs/ref/checks.txt
@@ -223,6 +223,15 @@ Model fields
   4.0. *This check appeared in Django 3.1 and 3.2*.
 * **fields.E904**: ``django.contrib.postgres.fields.JSONField`` is removed
   except for support in historical migrations.
+* **fields.W905**: ``django.contrib.postgres.fields.CICharField`` is
+  deprecated. Support for it (except in historical migrations) will be removed
+  in Django 5.1.
+* **fields.W906**: ``django.contrib.postgres.fields.CIEmailField`` is
+  deprecated. Support for it (except in historical migrations) will be removed
+  in Django 5.1.
+* **fields.W907**: ``django.contrib.postgres.fields.CITextField`` is
+  deprecated. Support for it (except in historical migrations) will be removed
+  in Django 5.1.
 
 File fields
 ~~~~~~~~~~~
@@ -851,6 +860,7 @@ fields:
 * **postgres.E003**: ``<field>`` default should be a callable instead of an
   instance so that it's not shared between all field instances. *This check was
   changed to* ``fields.E010`` *in Django 3.1*.
+* **postgres.W004**: Base field for array has warnings: ...
 
 ``sites``
 ---------
diff --git a/docs/ref/contrib/postgres/fields.txt b/docs/ref/contrib/postgres/fields.txt
index 25ca442b6f..820f6de956 100644
--- a/docs/ref/contrib/postgres/fields.txt
+++ b/docs/ref/contrib/postgres/fields.txt
@@ -259,6 +259,8 @@ transform do not change. For example::
 
 .. class:: CIText(**options)
 
+    .. deprecated:: 4.2
+
     A mixin to create case-insensitive text fields backed by the citext_ type.
     Read about `the performance considerations`_ prior to using it.
 
@@ -274,9 +276,29 @@ transform do not change. For example::
     Several fields that use the mixin are provided:
 
 .. class:: CICharField(**options)
+
+    .. deprecated:: 4.2
+
+        ``CICharField`` is deprecated in favor of
+        ``CharField(db_collation="…")`` with a case-insensitive
+        non-deterministic collation.
+
 .. class:: CIEmailField(**options)
+
+    .. deprecated:: 4.2
+
+        ``CIEmailField`` is deprecated in favor of
+        ``EmailField(db_collation="…")`` with a case-insensitive
+        non-deterministic collation.
+
 .. class:: CITextField(**options)
 
+    .. deprecated:: 4.2
+
+        ``CITextField`` is deprecated in favor of
+        ``TextField(db_collation="…")`` with a case-insensitive
+        non-deterministic collation.
+
     These fields subclass :class:`~django.db.models.CharField`,
     :class:`~django.db.models.EmailField`, and
     :class:`~django.db.models.TextField`, respectively.
diff --git a/docs/releases/1.11.txt b/docs/releases/1.11.txt
index 4716307526..5da81cd739 100644
--- a/docs/releases/1.11.txt
+++ b/docs/releases/1.11.txt
@@ -215,11 +215,11 @@ Minor features
   parameter to specify a custom class to encode data types not supported by the
   standard encoder.
 
-* The new :class:`~django.contrib.postgres.fields.CIText` mixin and
+* The new ``CIText`` mixin and
   :class:`~django.contrib.postgres.operations.CITextExtension` migration
   operation allow using PostgreSQL's ``citext`` extension for case-insensitive
-  lookups. Three fields are provided: :class:`.CICharField`,
-  :class:`.CIEmailField`, and :class:`.CITextField`.
+  lookups. Three fields are provided: ``CICharField``, ``CIEmailField``, and
+  ``CITextField``.
 
 * The new :class:`~django.contrib.postgres.aggregates.JSONBAgg` allows
   aggregating values as a JSON array.
diff --git a/docs/releases/4.2.txt b/docs/releases/4.2.txt
index fefba040e2..e3553e737b 100644
--- a/docs/releases/4.2.txt
+++ b/docs/releases/4.2.txt
@@ -351,3 +351,17 @@ Miscellaneous
 * ``django.contrib.auth.hashers.SHA1PasswordHasher``,
   ``django.contrib.auth.hashers.UnsaltedSHA1PasswordHasher``, and
   ``django.contrib.auth.hashers.UnsaltedMD5PasswordHasher`` are deprecated.
+
+* ``django.contrib.postgres.fields.CICharField`` is deprecated in favor of
+  ``CharField(db_collation="…")`` with a case-insensitive non-deterministic
+  collation.
+
+* ``django.contrib.postgres.fields.CIEmailField`` is deprecated in favor of
+  ``EmailField(db_collation="…")`` with a case-insensitive non-deterministic
+  collation.
+
+* ``django.contrib.postgres.fields.CITextField`` is deprecated in favor of
+  ``TextField(db_collation="…")`` with a case-insensitive non-deterministic
+  collation.
+
+* ``django.contrib.postgres.fields.CIText`` mixin is deprecated.
diff --git a/tests/backends/postgresql/tests.py b/tests/backends/postgresql/tests.py
index 63d7064aac..e28acef2c0 100644
--- a/tests/backends/postgresql/tests.py
+++ b/tests/backends/postgresql/tests.py
@@ -283,6 +283,7 @@ class Tests(TestCase):
         for lookup in lookups:
             with self.subTest(lookup=lookup):
                 self.assertIn("::text", do.lookup_cast(lookup))
+        # RemovedInDjango51Warning.
         for lookup in lookups:
             for field_type in ("CICharField", "CIEmailField", "CITextField"):
                 with self.subTest(lookup=lookup, field_type=field_type):
diff --git a/tests/invalid_models_tests/test_deprecated_fields.py b/tests/invalid_models_tests/test_deprecated_fields.py
index 3f3953496c..7b1e3fb7ac 100644
--- a/tests/invalid_models_tests/test_deprecated_fields.py
+++ b/tests/invalid_models_tests/test_deprecated_fields.py
@@ -85,3 +85,65 @@ class DeprecatedFieldsTests(SimpleTestCase):
                 ),
             ],
         )
+
+    @skipUnless(connection.vendor == "postgresql", "PostgreSQL specific SQL")
+    def test_postgres_ci_fields_deprecated(self):
+        from django.contrib.postgres.fields import (
+            ArrayField,
+            CICharField,
+            CIEmailField,
+            CITextField,
+        )
+
+        class PostgresCIFieldsModel(models.Model):
+            ci_char = CICharField(max_length=255)
+            ci_email = CIEmailField()
+            ci_text = CITextField()
+            array_ci_text = ArrayField(CITextField())
+
+        self.assertEqual(
+            PostgresCIFieldsModel.check(),
+            [
+                checks.Warning(
+                    "django.contrib.postgres.fields.CICharField is deprecated. Support "
+                    "for it (except in historical migrations) will be removed in "
+                    "Django 5.1.",
+                    hint=(
+                        'Use CharField(db_collation="…") with a case-insensitive '
+                        "non-deterministic collation instead."
+                    ),
+                    obj=PostgresCIFieldsModel._meta.get_field("ci_char"),
+                    id="fields.W905",
+                ),
+                checks.Warning(
+                    "django.contrib.postgres.fields.CIEmailField is deprecated. "
+                    "Support for it (except in historical migrations) will be removed "
+                    "in Django 5.1.",
+                    hint=(
+                        'Use EmailField(db_collation="…") with a case-insensitive '
+                        "non-deterministic collation instead."
+                    ),
+                    obj=PostgresCIFieldsModel._meta.get_field("ci_email"),
+                    id="fields.W906",
+                ),
+                checks.Warning(
+                    "django.contrib.postgres.fields.CITextField is deprecated. Support "
+                    "for it (except in historical migrations) will be removed in "
+                    "Django 5.1.",
+                    hint=(
+                        'Use TextField(db_collation="…") with a case-insensitive '
+                        "non-deterministic collation instead."
+                    ),
+                    obj=PostgresCIFieldsModel._meta.get_field("ci_text"),
+                    id="fields.W907",
+                ),
+                checks.Warning(
+                    "Base field for array has warnings:\n"
+                    "    django.contrib.postgres.fields.CITextField is deprecated. "
+                    "Support for it (except in historical migrations) will be removed "
+                    "in Django 5.1. (fields.W907)",
+                    obj=PostgresCIFieldsModel._meta.get_field("array_ci_text"),
+                    id="postgres.W004",
+                ),
+            ],
+        )
diff --git a/tests/postgres_tests/fields.py b/tests/postgres_tests/fields.py
index 2d62e26a92..1565b5ed43 100644
--- a/tests/postgres_tests/fields.py
+++ b/tests/postgres_tests/fields.py
@@ -7,12 +7,12 @@ import enum
 from django.db import models
 
 try:
+    from django.contrib.postgres.fields import CICharField  # RemovedInDjango51Warning.
+    from django.contrib.postgres.fields import CIEmailField  # RemovedInDjango51Warning.
+    from django.contrib.postgres.fields import CITextField  # RemovedInDjango51Warning.
     from django.contrib.postgres.fields import (
         ArrayField,
         BigIntegerRangeField,
-        CICharField,
-        CIEmailField,
-        CITextField,
         DateRangeField,
         DateTimeRangeField,
         DecimalRangeField,
@@ -47,9 +47,9 @@ except ImportError:
 
     ArrayField = DummyArrayField
     BigIntegerRangeField = models.Field
-    CICharField = models.Field
-    CIEmailField = models.Field
-    CITextField = models.Field
+    CICharField = models.Field  # RemovedInDjango51Warning.
+    CIEmailField = models.Field  # RemovedInDjango51Warning.
+    CITextField = models.Field  # RemovedInDjango51Warning.
     DateRangeField = models.Field
     DateTimeRangeField = DummyContinuousRangeField
     DecimalRangeField = DummyContinuousRangeField
diff --git a/tests/postgres_tests/migrations/0002_create_test_models.py b/tests/postgres_tests/migrations/0002_create_test_models.py
index 1b05435494..a1d9a942d0 100644
--- a/tests/postgres_tests/migrations/0002_create_test_models.py
+++ b/tests/postgres_tests/migrations/0002_create_test_models.py
@@ -291,6 +291,7 @@ class Migration(migrations.Migration):
             options=None,
             bases=None,
         ),
+        # RemovedInDjango51Warning.
         migrations.CreateModel(
             name="CITestModel",
             fields=[
diff --git a/tests/postgres_tests/models.py b/tests/postgres_tests/models.py
index 8f27838ad5..05f2732fb8 100644
--- a/tests/postgres_tests/models.py
+++ b/tests/postgres_tests/models.py
@@ -119,6 +119,7 @@ class Character(models.Model):
     name = models.CharField(max_length=255)
 
 
+# RemovedInDjango51Warning.
 class CITestModel(PostgreSQLModel):
     name = CICharField(primary_key=True, max_length=255)
     email = CIEmailField()
diff --git a/tests/postgres_tests/test_citext.py b/tests/postgres_tests/test_citext.py
index f1c13184b6..314f2e40d3 100644
--- a/tests/postgres_tests/test_citext.py
+++ b/tests/postgres_tests/test_citext.py
@@ -1,3 +1,4 @@
+# RemovedInDjango51Warning.
 """
 The citext PostgreSQL extension supports indexing of case-insensitive text
 strings and thus eliminates the need for operations such as iexact and other
@@ -5,6 +6,7 @@ modifiers to enforce use of an index.
 """
 from django.db import IntegrityError
 from django.test.utils import modify_settings
+from django.utils.deprecation import RemovedInDjango51Warning
 
 from . import PostgreSQLTestCase
 from .models import CITestModel
@@ -82,3 +84,10 @@ class CITextTestCase(PostgreSQLTestCase):
                 self.assertSequenceEqual(
                     CITestModel.objects.filter(**query), [self.john]
                 )
+
+    def test_citext_deprecated(self):
+        from django.contrib.postgres.fields import CIText
+
+        msg = "django.contrib.postgres.fields.CIText mixin is deprecated."
+        with self.assertRaisesMessage(RemovedInDjango51Warning, msg):
+            CIText()
diff --git a/tests/runtests.py b/tests/runtests.py
index 3bbaf5ada7..b678988391 100755
--- a/tests/runtests.py
+++ b/tests/runtests.py
@@ -244,6 +244,13 @@ def setup_collect_tests(start_at, start_after, test_labels=None):
     settings.LOGGING = log_config
     settings.SILENCED_SYSTEM_CHECKS = [
         "fields.W342",  # ForeignKey(unique=True) -> OneToOneField
+        # django.contrib.postgres.fields.CICharField deprecated.
+        "fields.W905",
+        "postgres.W004",
+        # django.contrib.postgres.fields.CIEmailField deprecated.
+        "fields.W906",
+        # django.contrib.postgres.fields.CITextField deprecated.
+        "fields.W907",
     ]
 
     # RemovedInDjango50Warning