[2.1.x] Fixed #29496 -- Fixed crash on Oracle when converting a non-unique field to primary key.

Thanks Tim Graham for the review.
Backport of 6dd4edb1b4f5441c5f543e29395039839c50d10b from master

2 files changed, 15 insertions, 1 deletions

diff --git a/tests/schema/models.py b/tests/schema/models.py
index 4512d8bc01..f6bdbd8815 100644
--- a/tests/schema/models.py
+++ b/tests/schema/models.py
@@ -12,6 +12,7 @@ class Author(models.Model):
     name = models.CharField(max_length=255)
     height = models.PositiveIntegerField(null=True, blank=True)
     weight = models.IntegerField(null=True, blank=True)
+    uuid = models.UUIDField(null=True)
 
     class Meta:
         apps = new_apps
diff --git a/tests/schema/tests.py b/tests/schema/tests.py
index e1bf438ca3..f18b68d04d 100644
--- a/tests/schema/tests.py
+++ b/tests/schema/tests.py
@@ -12,7 +12,7 @@ from django.db.models.deletion import CASCADE, PROTECT
 from django.db.models.fields import (
     AutoField, BigAutoField, BigIntegerField, BinaryField, BooleanField,
     CharField, DateField, DateTimeField, IntegerField, PositiveIntegerField,
-    SlugField, TextField, TimeField,
+    SlugField, TextField, TimeField, UUIDField,
 )
 from django.db.models.fields.related import (
     ForeignKey, ForeignObject, ManyToManyField, OneToOneField,
@@ -603,6 +603,19 @@ class SchemaTests(TransactionTestCase):
         with connection.schema_editor() as editor:
             editor.alter_field(Author, old_field, new_field, strict=True)
 
+    def test_alter_not_unique_field_to_primary_key(self):
+        # Create the table.
+        with connection.schema_editor() as editor:
+            editor.create_model(Author)
+        # Change UUIDField to primary key.
+        old_field = Author._meta.get_field('uuid')
+        new_field = UUIDField(primary_key=True)
+        new_field.set_attributes_from_name('uuid')
+        new_field.model = Author
+        with connection.schema_editor() as editor:
+            editor.remove_field(Author, Author._meta.get_field('id'))
+            editor.alter_field(Author, old_field, new_field, strict=True)
+
     def test_alter_text_field(self):
         # Regression for "BLOB/TEXT column 'info' can't have a default value")
         # on MySQL.