From e4684220af058789a9d2673a3503d2f88d8aa94a Mon Sep 17 00:00:00 2001
From: Ngalim Siregar <ngalim.siregar@gmail.com>
Date: Wed, 31 Jul 2019 19:02:15 +0700
Subject: [PATCH] Fixed #30664 -- Fixed migrations crash when altering table on
 SQLite or altering AutoField/BigAutoField on PostgreSQL for models with
 quoted db_table.

---
 django/db/backends/postgresql/schema.py |  3 ++-
 django/db/backends/sqlite3/schema.py    |  3 ++-
 tests/schema/tests.py                   | 18 ++++++++++++++++++
 3 files changed, 22 insertions(+), 2 deletions(-)

diff --git a/django/db/backends/postgresql/schema.py b/django/db/backends/postgresql/schema.py
index 82e91ce8401..9e07bccf8b8 100644
--- a/django/db/backends/postgresql/schema.py
+++ b/django/db/backends/postgresql/schema.py
@@ -2,6 +2,7 @@ import psycopg2
 
 from django.db.backends.base.schema import BaseDatabaseSchemaEditor
 from django.db.backends.ddl_references import IndexColumns
+from django.db.backends.utils import strip_quotes
 
 
 class DatabaseSchemaEditor(BaseDatabaseSchemaEditor):
@@ -67,7 +68,7 @@ class DatabaseSchemaEditor(BaseDatabaseSchemaEditor):
         if self._field_data_type(old_field) != self._field_data_type(new_field):
             self.sql_alter_column_type += ' USING %(column)s::%(type)s'
         # Make ALTER TYPE with SERIAL make sense.
-        table = model._meta.db_table
+        table = strip_quotes(model._meta.db_table)
         if new_type.lower() in ("serial", "bigserial"):
             column = new_field.column
             sequence_name = "%s_%s_seq" % (table, column)
diff --git a/django/db/backends/sqlite3/schema.py b/django/db/backends/sqlite3/schema.py
index b1c91dba3c1..029e22e1888 100644
--- a/django/db/backends/sqlite3/schema.py
+++ b/django/db/backends/sqlite3/schema.py
@@ -4,6 +4,7 @@ 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.backends.utils import strip_quotes
 from django.db.models import UniqueConstraint
 from django.db.transaction import atomic
 from django.db.utils import NotSupportedError
@@ -263,7 +264,7 @@ class DatabaseSchemaEditor(BaseDatabaseSchemaEditor):
         body_copy = copy.deepcopy(body)
         meta_contents = {
             'app_label': model._meta.app_label,
-            'db_table': 'new__%s' % model._meta.db_table,
+            'db_table': 'new__%s' % strip_quotes(model._meta.db_table),
             'unique_together': unique_together,
             'index_together': index_together,
             'indexes': indexes,
diff --git a/tests/schema/tests.py b/tests/schema/tests.py
index 2a22e9dec32..287ef200da7 100644
--- a/tests/schema/tests.py
+++ b/tests/schema/tests.py
@@ -649,6 +649,24 @@ class SchemaTests(TransactionTestCase):
             editor.remove_field(Author, Author._meta.get_field('id'))
             editor.alter_field(Author, old_field, new_field, strict=True)
 
+    @isolate_apps('schema')
+    def test_alter_primary_key_quoted_db_table(self):
+        class Foo(Model):
+            class Meta:
+                app_label = 'schema'
+                db_table = '"foo"'
+
+        with connection.schema_editor() as editor:
+            editor.create_model(Foo)
+        self.isolated_local_models = [Foo]
+        old_field = Foo._meta.get_field('id')
+        new_field = BigAutoField(primary_key=True)
+        new_field.model = Foo
+        new_field.set_attributes_from_name('id')
+        with connection.schema_editor() as editor:
+            editor.alter_field(Foo, old_field, new_field, strict=True)
+        Foo.objects.create()
+
     def test_alter_text_field(self):
         # Regression for "BLOB/TEXT column 'info' can't have a default value")
         # on MySQL.