[1.9.x] Fixed #25922 -- Fixed migrate --fake-initial detection of many-to-many tables.

Backport of fa9ce4e9a691e4f8c8b093784bac752e488dc60b from master

1 files changed, 17 insertions, 4 deletions

diff --git a/django/db/migrations/executor.py b/django/db/migrations/executor.py
index 3779b626ec..b1a8383100 100644
--- a/django/db/migrations/executor.py
+++ b/django/db/migrations/executor.py
@@ -265,6 +265,7 @@ class MigrationExecutor(object):
         apps = after_state.apps
         found_create_model_migration = False
         found_add_field_migration = False
+        existing_table_names = self.connection.introspection.table_names(self.connection.cursor())
         # Make sure all create model and add field operations are done
         for operation in migration.operations:
             if isinstance(operation, migrations.CreateModel):
@@ -275,7 +276,7 @@ class MigrationExecutor(object):
                     model = global_apps.get_model(model._meta.swapped)
                 if model._meta.proxy or not model._meta.managed:
                     continue
-                if model._meta.db_table not in self.connection.introspection.table_names(self.connection.cursor()):
+                if model._meta.db_table not in existing_table_names:
                     return False, project_state
                 found_create_model_migration = True
             elif isinstance(operation, migrations.AddField):
@@ -288,9 +289,21 @@ class MigrationExecutor(object):
                     continue
 
                 table = model._meta.db_table
-                db_field = model._meta.get_field(operation.name).column
-                fields = self.connection.introspection.get_table_description(self.connection.cursor(), table)
-                if db_field not in (f.name for f in fields):
+                field = model._meta.get_field(operation.name)
+
+                # Handle implicit many-to-many tables created by AddField.
+                if field.many_to_many:
+                    if field.remote_field.through._meta.db_table not in existing_table_names:
+                        return False, project_state
+                    else:
+                        found_add_field_migration = True
+                        continue
+
+                column_names = [
+                    column.name for column in
+                    self.connection.introspection.get_table_description(self.connection.cursor(), table)
+                ]
+                if field.column not in column_names:
                     return False, project_state
                 found_add_field_migration = True
         # If we get this far and we found at least one CreateModel or AddField migration,