Django可复用CMS应用迁移依赖问题：兼容多版本django-cms方案咨询

Great question—this is a common pitfall when building reusable Django apps that target multiple versions of a dependency like django-cms. Let's break down the best approaches to make your migrations compatible across both versions:

Recommended: Remove All django-cms-Specific Migration Dependencies #

Unless your app's migrations directly modify django-cms core models or rely on schema changes introduced in a specific cms migration (which is unlikely for most plugins), you don't need to tie your migrations to specific cms migration versions. Here's how to fix this:

1. Update existing migrations

   • For your older 3.4.x-era migration: Replace the cms dependency with a dependency on your app's own prior migration (or leave it empty if it's your app's first migration). For example:

     dependencies = [
         # Replace ('cms', '0016_auto_20160608_1535'),
         ('your_app_name', '0001_initial'),  # Use your app's actual initial migration name
     ]
     

   • For your new 3.5.2-era migration: Swap the cms dependency to point to the latest migration in your own app (not cms). For example:

     dependencies = [
         # Replace ('cms', '0020_old_tree_cleanup'),
         ('your_app_name', '0002_existing_plugin'),  # Use your app's last migration before this one
     ]
     

2. Why this works

   • django-cms's core CMSPlugin model (which your plugins inherit from) has a stable schema across 3.4.x and 3.5.x. The later cms migrations like 0020_old_tree_cleanup are for internal cleanup or optimizations that don't affect plugin models.
   • By relying only on your app's own migrations, you decouple your app from specific cms versions, making it usable across both 3.4.x and 3.5.x without migration errors.

Alternative: Conditional Dependencies (Only If Absolutely Necessary) #

If your migration does depend on a schema change exclusive to django-cms 3.5.x (e.g., a new field on CMSPlugin), you'll need to handle version-specific migrations. This is more complex, but here's a rough approach:

• Create separate migration files for 3.4.x and 3.5.x environments.
• Use logic in your app's migrations/__init__.py to load the appropriate migration based on the installed django-cms version.
• Note: This adds significant maintenance overhead, so only use this if you can't avoid relying on version-specific cms changes.

Key Testing Step #

After adjusting your migrations, test them in both environments:

• Spin up a project with django-cms 3.4.x, install your app, and run python manage.py migrate your_app_name to confirm no errors.
• Repeat the process with django-cms 3.5.2 to ensure compatibility.

内容的提问来源于stack exchange，提问作者benzkji