Fixed #27859 -- Ignored db_index for TextField/BinaryField on Oracle and MySQL.

Thanks Zubair Alam for the initial patch and Tim Graham for the review.

3 files changed, 43 insertions, 6 deletions

diff --git a/tests/invalid_models_tests/test_ordinary_fields.py b/tests/invalid_models_tests/test_ordinary_fields.py
index 90f4b31902..cad375aae5 100644
--- a/tests/invalid_models_tests/test_ordinary_fields.py
+++ b/tests/invalid_models_tests/test_ordinary_fields.py
@@ -2,7 +2,7 @@ import unittest
 
 from django.core.checks import Error, Warning as DjangoWarning
 from django.db import connection, models
-from django.test import SimpleTestCase, TestCase
+from django.test import SimpleTestCase, TestCase, skipIfDBFeature
 from django.test.utils import isolate_apps, override_settings
 from django.utils.timezone import now
 
@@ -646,3 +646,26 @@ class TimeFieldTests(TestCase):
     @override_settings(USE_TZ=True)
     def test_fix_default_value_tz(self):
         self.test_fix_default_value()
+
+
+@isolate_apps('invalid_models_tests')
+class TextFieldTests(TestCase):
+
+    @skipIfDBFeature('supports_index_on_text_field')
+    def test_max_length_warning(self):
+        class Model(models.Model):
+            value = models.TextField(db_index=True)
+        field = Model._meta.get_field('value')
+        field_type = field.db_type(connection)
+        self.assertEqual(field.check(), [
+            DjangoWarning(
+                '%s does not support a database index on %s columns.'
+                % (connection.display_name, field_type),
+                hint=(
+                    "An index won't be created. Silence this warning if you "
+                    "don't care about it."
+                ),
+                obj=field,
+                id='fields.W162',
+            )
+        ])
diff --git a/tests/schema/models.py b/tests/schema/models.py
index 0c73760d96..0e04dbab87 100644
--- a/tests/schema/models.py
+++ b/tests/schema/models.py
@@ -17,6 +17,13 @@ class Author(models.Model):
         apps = new_apps
 
 
+class AuthorTextFieldWithIndex(models.Model):
+    text_field = models.TextField(db_index=True)
+
+    class Meta:
+        apps = new_apps
+
+
 class AuthorWithDefaultHeight(models.Model):
     name = models.CharField(max_length=255)
     height = models.PositiveIntegerField(null=True, blank=True, default=42)
diff --git a/tests/schema/tests.py b/tests/schema/tests.py
index 17a4d7c715..ef4b192a36 100644
--- a/tests/schema/tests.py
+++ b/tests/schema/tests.py
@@ -29,11 +29,11 @@ from .fields import (
     CustomManyToManyField, InheritedManyToManyField, MediumBlobField,
 )
 from .models import (
-    Author, AuthorWithDefaultHeight, AuthorWithEvenLongerName,
-    AuthorWithIndexedName, Book, BookForeignObj, BookWeak, BookWithLongName,
-    BookWithO2O, BookWithoutAuthor, BookWithSlug, IntegerPK, Node, Note,
-    NoteRename, Tag, TagIndexed, TagM2MTest, TagUniqueRename, Thing,
-    UniqueTest, new_apps,
+    Author, AuthorTextFieldWithIndex, AuthorWithDefaultHeight,
+    AuthorWithEvenLongerName, AuthorWithIndexedName, Book, BookForeignObj,
+    BookWeak, BookWithLongName, BookWithO2O, BookWithoutAuthor, BookWithSlug,
+    IntegerPK, Node, Note, NoteRename, Tag, TagIndexed, TagM2MTest,
+    TagUniqueRename, Thing, UniqueTest, new_apps,
 )
 
 
@@ -1749,6 +1749,13 @@ class SchemaTests(TransactionTestCase):
             self.get_indexes(Book._meta.db_table),
         )
 
+    def test_text_field_with_db_index(self):
+        with connection.schema_editor() as editor:
+            editor.create_model(AuthorTextFieldWithIndex)
+        # The text_field index is present if the database supports it.
+        assertion = self.assertIn if connection.features.supports_index_on_text_field else self.assertNotIn
+        assertion('text_field', self.get_indexes(AuthorTextFieldWithIndex._meta.db_table))
+
     def test_primary_key(self):
         """
         Tests altering of the primary key