Cop for detecting consecutive after_commit hooks for the same model

[thisismydesign]

Problem

There can only be one after_commit hook defined for a model. This, however, is pretty confusing in the light of the on: option and its abbreviations (after_create_commit, after_update_commit and after_destroy_commit). For example, the following examples all result in a single after_commit hook being defined:

after_create_commit :log_create
after_update_commit :log_update

after_commit :callback, :on => :create
after_commit :callback, :on => :update, :if => :condition

See also:

• after_create_commit and after_update_commit alias don't always run when next to each other rails/rails#29554
• consecutive after_commit callbacks overwrite each other rails/rails#19590

Interestingly enough, the following works

after_create_commit -> { foo }
after_update_commit -> { foo }

See also:

• consecutive after_commit callbacks overwrite each other rails/rails#19590 (comment)
• after_create_commit and after_update_commit alias don't always run when next to each other rails/rails#29554 (comment)

So the cop could recommend to only use this format.

Describe the solution you'd like

I'd like rubocop to be able to detect this scenario and only allow for one after_commit and its abbreviations per model.

[Kani999]

Still same problem. Costs me a lot of debugging.

Weird is that
after_create_commit :add_ac_role - Does not work
after_update_commit :add_ac_role - Does work

[thisismydesign]

Both "work" it's just that they overwrite each other.

[fatkodima]

Hey, I have implemented a cop for this 😄