Fixed #28849 -- Fixed referenced table and column rename on SQLite.

Thanks Ramiro for the input and Tim for the review.

1 files changed, 58 insertions, 2 deletions

diff --git a/django/db/backends/sqlite3/schema.py b/django/db/backends/sqlite3/schema.py
index 71f6c1c303..c2950ffd2e 100644
--- a/django/db/backends/sqlite3/schema.py
+++ b/django/db/backends/sqlite3/schema.py
@@ -5,6 +5,8 @@ from decimal import Decimal
 from django.apps.registry import Apps
 from django.db.backends.base.schema import BaseDatabaseSchemaEditor
 from django.db.backends.ddl_references import Statement
+from django.db.transaction import atomic
+from django.db.utils import NotSupportedError
 
 
 class DatabaseSchemaEditor(BaseDatabaseSchemaEditor):
@@ -53,6 +55,58 @@ class DatabaseSchemaEditor(BaseDatabaseSchemaEditor):
         else:
             raise ValueError("Cannot quote parameter value %r of type %s" % (value, type(value)))
 
+    def alter_db_table(self, model, old_db_table, new_db_table, disable_constraints=True):
+        if model._meta.related_objects and disable_constraints:
+            if self.connection.in_atomic_block:
+                raise NotSupportedError((
+                    'Renaming the %r table while in a transaction is not '
+                    'supported on SQLite because it would break referential '
+                    'integrity. Try adding `atomic = False` to the Migration class.'
+                ) % old_db_table)
+            self.connection.enable_constraint_checking()
+            super().alter_db_table(model, old_db_table, new_db_table)
+            self.connection.disable_constraint_checking()
+        else:
+            super().alter_db_table(model, old_db_table, new_db_table)
+
+    def alter_field(self, model, old_field, new_field, strict=False):
+        old_field_name = old_field.name
+        if (new_field.name != old_field_name and
+                any(r.field_name == old_field.name for r in model._meta.related_objects)):
+            if self.connection.in_atomic_block:
+                raise NotSupportedError((
+                    'Renaming the %r.%r column while in a transaction is not '
+                    'supported on SQLite because it would break referential '
+                    'integrity. Try adding `atomic = False` to the Migration class.'
+                ) % (model._meta.db_table, old_field_name))
+            with atomic(self.connection.alias):
+                super().alter_field(model, old_field, new_field, strict=strict)
+                # Follow SQLite's documented procedure for performing changes
+                # that don't affect the on-disk content.
+                # https://sqlite.org/lang_altertable.html#otheralter
+                with self.connection.cursor() as cursor:
+                    schema_version = cursor.execute('PRAGMA schema_version').fetchone()[0]
+                    cursor.execute('PRAGMA writable_schema = 1')
+                    table_name = model._meta.db_table
+                    references_template = ' REFERENCES "%s" ("%%s") ' % table_name
+                    old_column_name = old_field.get_attname_column()[1]
+                    new_column_name = new_field.get_attname_column()[1]
+                    search = references_template % old_column_name
+                    replacement = references_template % new_column_name
+                    cursor.execute('UPDATE sqlite_master SET sql = replace(sql, %s, %s)', (search, replacement))
+                    cursor.execute('PRAGMA schema_version = %d' % (schema_version + 1))
+                    cursor.execute('PRAGMA writable_schema = 0')
+                    # The integrity check will raise an exception and rollback
+                    # the transaction if the sqlite_master updates corrupt the
+                    # database.
+                    cursor.execute('PRAGMA integrity_check')
+            # Perform a VACUUM to refresh the database representation from
+            # the sqlite_master table.
+            with self.connection.cursor() as cursor:
+                cursor.execute('VACUUM')
+        else:
+            super().alter_field(model, old_field, new_field, strict=strict)
+
     def _remake_table(self, model, create_field=None, delete_field=None, alter_field=None):
         """
         Shortcut to transform a model from old_model into new_model
@@ -176,8 +230,10 @@ class DatabaseSchemaEditor(BaseDatabaseSchemaEditor):
 
         with altered_table_name(model, model._meta.db_table + "__old"):
             # Rename the old table to make way for the new
-            self.alter_db_table(model, temp_model._meta.db_table, model._meta.db_table)
-
+            self.alter_db_table(
+                model, temp_model._meta.db_table, model._meta.db_table,
+                disable_constraints=False,
+            )
             # Create a new table with the updated schema.
             self.create_model(temp_model)