From 910ecd1b8df7678f45c3d507dde6bcb1faafa243 Mon Sep 17 00:00:00 2001
From: Jacob Walls <jacobtylerwalls@gmail.com>
Date: Mon, 2 Aug 2021 11:07:58 -0400
Subject: [PATCH] Fixed #29063 -- Fixed migrate crash when specifying a name of
 partially applied squashed migrations.

---
 django/core/management/commands/migrate.py | 11 ++++++++-
 tests/migrations/test_commands.py          | 28 ++++++++++++++++++++++
 2 files changed, 38 insertions(+), 1 deletion(-)

diff --git a/django/core/management/commands/migrate.py b/django/core/management/commands/migrate.py
index 55b8faf38b..34fcb9bc58 100644
--- a/django/core/management/commands/migrate.py
+++ b/django/core/management/commands/migrate.py
@@ -140,7 +140,16 @@ class Command(BaseCommand):
                 except KeyError:
                     raise CommandError("Cannot find a migration matching '%s' from app '%s'." % (
                         migration_name, app_label))
-                targets = [(app_label, migration.name)]
+                target = (app_label, migration.name)
+                # Partially applied squashed migrations are not included in the
+                # graph, use the last replacement instead.
+                if (
+                    target not in executor.loader.graph.nodes and
+                    target in executor.loader.replacements
+                ):
+                    incomplete_migration = executor.loader.replacements[target]
+                    target = incomplete_migration.replaces[-1]
+                targets = [target]
             target_app_labels_only = False
         elif options['app_label']:
             targets = [key for key in executor.loader.graph.leaf_nodes() if key[0] == app_label]
diff --git a/tests/migrations/test_commands.py b/tests/migrations/test_commands.py
index b0cb0bb0b6..daeeaf8edb 100644
--- a/tests/migrations/test_commands.py
+++ b/tests/migrations/test_commands.py
@@ -951,6 +951,34 @@ class MigrateTests(MigrationTestBase):
         )
         # No changes were actually applied so there is nothing to rollback
 
+    def test_migrate_partially_applied_squashed_migration(self):
+        """
+        Migrating to a squashed migration specified by name should succeed
+        even if it is partially applied.
+        """
+        with self.temporary_migration_module(module='migrations.test_migrations'):
+            recorder = MigrationRecorder(connection)
+            try:
+                call_command('migrate', 'migrations', '0001_initial', verbosity=0)
+                call_command(
+                    'squashmigrations',
+                    'migrations',
+                    '0002',
+                    interactive=False,
+                    verbosity=0,
+                )
+                call_command(
+                    'migrate',
+                    'migrations',
+                    '0001_squashed_0002_second',
+                    verbosity=0,
+                )
+                applied_migrations = recorder.applied_migrations()
+                self.assertIn(('migrations', '0002_second'), applied_migrations)
+            finally:
+                # Unmigrate everything.
+                call_command('migrate', 'migrations', 'zero', verbosity=0)
+
     @override_settings(MIGRATION_MODULES={'migrations': 'migrations.test_migrations'})
     def test_migrate_inconsistent_history(self):
         """