Fixed #23745 -- Reused states as much as possible in migrations

Thanks Tim Graham and Markus Holtermann for the reviews.

1 files changed, 13 insertions, 11 deletions

diff --git a/django/db/migrations/executor.py b/django/db/migrations/executor.py
index 2e42e7c6d5..a7989c4107 100644
--- a/django/db/migrations/executor.py
+++ b/django/db/migrations/executor.py
@@ -98,13 +98,13 @@ class MigrationExecutor(object):
             self.progress_callback("apply_start", migration, fake)
         if not fake:
             # Test to see if this is an already-applied initial migration
-            if self.detect_soft_applied(state, migration):
+            applied, state = self.detect_soft_applied(state, migration)
+            if applied:
                 fake = True
             else:
                 # Alright, do it normally
                 with self.connection.schema_editor() as schema_editor:
-                    project_state = self.loader.project_state((migration.app_label, migration.name), at_end=False)
-                    migration.apply(project_state, schema_editor)
+                    state = migration.apply(state, schema_editor)
         # For replacement migrations, record individual statuses
         if migration.replaces:
             for app_label, name in migration.replaces:
@@ -124,8 +124,7 @@ class MigrationExecutor(object):
             self.progress_callback("unapply_start", migration, fake)
         if not fake:
             with self.connection.schema_editor() as schema_editor:
-                project_state = self.loader.project_state((migration.app_label, migration.name), at_end=False)
-                migration.unapply(project_state, schema_editor)
+                state = migration.unapply(state, schema_editor)
         # For replacement migrations, record individual statuses
         if migration.replaces:
             for app_label, name in migration.replaces:
@@ -143,12 +142,15 @@ class MigrationExecutor(object):
         tables it would create exist. This is intended only for use
         on initial migrations (as it only looks for CreateModel).
         """
-        project_state = self.loader.project_state((migration.app_label, migration.name), at_end=True)
-        apps = project_state.apps
-        found_create_migration = False
         # Bail if the migration isn't the first one in its app
         if [name for app, name in migration.dependencies if app == migration.app_label]:
-            return False
+            return False, project_state
+        if project_state is None:
+            after_state = self.loader.project_state((migration.app_label, migration.name), at_end=True)
+        else:
+            after_state = migration.mutate_state(project_state)
+        apps = after_state.apps
+        found_create_migration = False
         # Make sure all create model are done
         for operation in migration.operations:
             if isinstance(operation, migrations.CreateModel):
@@ -158,8 +160,8 @@ class MigrationExecutor(object):
                     # main app cache, as it's not a direct dependency.
                     model = global_apps.get_model(model._meta.swapped)
                 if model._meta.db_table not in self.connection.introspection.table_names(self.connection.cursor()):
-                    return False
+                    return False, project_state
                 found_create_migration = True
         # If we get this far and we found at least one CreateModel migration,
         # the migration is considered implicitly applied.
-        return found_create_migration
+        return found_create_migration, after_state