Changing of model's verbose_name does not change the names of the model's permissions

[Dmitry Burakov]

I've found that changing the "verbose_name" of the Meta class of a model and than running migrations does not change the names of the model's permissions.

Steps to reproduce:

1. Create a new model

class AwesomeModel(models.Model):
    class Meta:
        verbose_name = "My awesome model"

2. Run "makemigrations" and than "migrate"
3. Look at the generated permissions

select * from auth_permission;
 id  |                  name                  | content_type_id |             codename
-----+----------------------------------------+-----------------+----------------------------------
   1 | Can add my awesome model               |               2 | add_awesomemodel
   2 | Can change my awesome model            |               2 | change_awesomemodel
   3 | Can delete my awesome model            |               2 | delete_awesomemodel

4. Change the "verbose_name" of the Meta class of the model

class AwesomeModel(models.Model):
    class Meta:
        verbose_name = "My really awesome model"

5. Run "makemigrations" and than "migrate" again
6. Look at the generated permissions agaun

select * from auth_permission;
 id  |                  name                  | content_type_id |             codename
-----+----------------------------------------+-----------------+----------------------------------
   1 | Can add my awesome model               |               2 | add_awesomemodel
   2 | Can change my awesome model            |               2 | change_awesomemodel
   3 | Can delete my awesome model            |               2 | delete_awesomemodel

As you can see the names of the model's permissions are not changed.
But! If now you drop the database and apply all the migrations to the empty database - the permissions will have correct names

select * from auth_permission;
 id  |                  name                  | content_type_id |             codename
-----+----------------------------------------+-----------------+----------------------------------
   1 | Can add my really awesome model        |               2 | add_awesomemodel
   2 | Can change my really awesome model     |               2 | change_awesomemodel
   3 | Can delete my really awesome model     |               2 | delete_awesomemodel

[Roman Hudec]

I've tried to implement this in the management command, that handles creating non-existing permissions after migrating an app.

Here's a PR ​https://github.com/django/django/pull/6778

[Tim Graham]

I left a comment for improvement on the PR. Also tests are needed.

[Roman Hudec]

I've tried the suggested injecting a migration operation approach, but somehow ended up with an unexpected exception saying Permission model cannot resolve 'content_type' into a field.

then i've tried optimizing my previous approach by only checking permissions for models that had verbose_name altered during the migration. that should be almost as effective as the suggested approach, and passed the test I've written, so I created a new PR ( ​https://github.com/django/django/pull/6837 ) for that approach.

[Tim Graham]

#27489 "Renaming a model doesn't rename the permission name and codename" is a related issue that would be useful to work on while in this area.