[Noah-Silvera]

What this adds

A new SolidusAdmin::Config.force_legacy_admin_proc preference. It receives the Rack request and returns whether that request should be served by the legacy admin (solidus_backend) instead of SolidusAdmin.

Until now the only switch was all-or-nothing: the solidus_admin=false cookie or query param. Stores that have heavily customized some legacy admin pages couldn't adopt the new admin at all. With this, you can send just the pages you haven't ported back to the legacy admin and use the new admin everywhere else.

It defaults to never forcing the legacy admin, so nothing changes unless you opt in.

Upgrading

New installs (solidus_admin:install) get everything automatically.

Existing apps need a one-time edit, because rerunning the generator adds a second SolidusAdmin mount instead of replacing the existing one. Apply this change to the SolidusAdmin::Engine mount in config/routes.rb (line numbers will differ in your app):

--- a/config/routes.rb
+++ b/config/routes.rb
@@
 mount SolidusAdmin::Engine, at: '/admin', constraints: ->(req) {
   req.cookies['solidus_admin'] != 'false' &&
-  req.params['solidus_admin'] != 'false'
+  req.params['solidus_admin'] != 'false' &&
+  !SolidusAdmin::Config.force_legacy_admin_proc.call(req)
 }

If you already customized the constraint, add !SolidusAdmin::Config.force_legacy_admin_proc.call(req) to your own logic. Until you do, setting the preference has no effect.

Using it

# config/initializers/solidus_admin.rb
SolidusAdmin::Config.force_legacy_admin_proc = ->(req) {
  req.path.start_with?('/admin/promotions')
}

The cookie and query param still work and take precedence.

Testing locally

This walks through both an existing app that upgrades without touching its routes, and a fresh install. It uses the Docker setup from the root README (docker-compose up -d first). Restart bin/dev after any change to config/routes.rb or config/initializers/, since neither is reloaded.

Throughout, "the two basic tests" are:

• A. Log in at http://localhost:3000/admin (admin@example.com / test123), open /admin/products and run document.body.className in DevTools. This is the new admin, so the result is 'bg-gray-15 font-sans text-sm'.
• B. Open /admin/products?solidus_admin=false. This is the legacy admin, so the result is 'admin '.

1. Baseline on main. Check out main, then build and start the sandbox:

   docker-compose exec app bin/sandbox   # replaces ./sandbox
   docker-compose exec app bin/dev       # http://localhost:3000

   Run tests A and B.

2. Switch to this branch. The sandbox is gitignored and loads the admin gem from ../admin, so it keeps working. Check out this branch, restart bin/dev, and run tests A and B again. Nothing should change.

3. Upgrade without touching the routes. The sandbox's mount is now the old one, without the new clause, like an existing app. Add this inside the configure block of sandbox/config/initializers/solidus_admin.rb, restart, and run tests A and B again:

   config.force_legacy_admin_proc = ->(req) { req.path.start_with?("/admin/products") }

   Both results are unchanged: /admin/products is still the new admin. The preference is set but nothing calls it, because the old mount doesn't consult it.

4. Edit the routes. Add && !SolidusAdmin::Config.force_legacy_admin_proc.call(req) to the constraint of the SolidusAdmin::Engine mount in sandbox/config/routes.rb, as described in "Upgrading" above, and restart. /admin/products now serves the legacy admin ('admin ') without any param, while /admin/stores still serves the new admin.

5. Fresh install on this branch. Rebuild the sandbox with docker-compose exec app bin/sandbox, start bin/dev, and confirm the generated sandbox/config/routes.rb already has !SolidusAdmin::Config.force_legacy_admin_proc.call(req) in the mount's constraint. Run tests A and B.

6. Use the proc on the fresh install. Add the force_legacy_admin_proc line from step 3 to the new sandbox's initializer and restart. /admin/products now serves the legacy admin, and no routes edit was needed.

🤖 Generated with Claude Code

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 92.58%. Comparing base (f41bf95) to head (daf65d7).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #6601      +/-   ##
==========================================
+ Coverage   92.48%   92.58%   +0.10%     
==========================================
  Files        1065     1065              
  Lines       21544    21546       +2     
==========================================
+ Hits        19924    19948      +24     
+ Misses       1620     1598      -22     

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[Noah-Silvera]

Just pushed to see if I could get the tests to pass

[Noah-Silvera]

Checks passed and Jared approves: @AlistairNorman could we merge this one?

[AlistairNorman]

Nice work, I think this will really help with adoption