Fixed #29063 -- Fixed migrate crash when specifying a name of partially applied squashed migrations.

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]

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):
         """