Renaming a field and other attributes result in deleting and recreating a new column.

[Corentin Bettiol]

Hi all,
When renaming a field of a model in Django, one would expect the makemigration command to realize it should only rename the column in the db.

However, when also renaming the verbose_name, the makemigration command will create a migration file which will delete the column (and all the data it contains), and create a new column.

See the resulting migrations files generated for an example (new project named "a", new app named "b", a simple model containing 2 fields).

I think the makemigration command should handle this case by not deleting data, because we expect it to know that it only needs to rename the column.

[Corentin Bettiol]

First migration: create the model in db, with 2 fields.

[Corentin Bettiol]

Working rename of a field: field "a_field" was renamed "a_field_renamed", using migrations.RenameField.

[Corentin Bettiol]

Nonworking migration: the field "another_field" was deleted, and a new field named "another_field_renamed" was created. Only difference with the previous migration is that the verbose_name of the field also changed.

[Mariusz Felisiak]

Migrations are unable to detect that field is renamed after any other attribute changes. You need to do this in two steps:

• rename a field (generate migrations).
• change a verbose name (generate migrations, this is a no-op).