Stop stubbing a private generator method to silence Thor command noise

[55728]

Summary

Running the test suite prints this line twice:

Could not find command "no_previous_refresh_token_column?".

It comes from spec/generators/previous_refresh_token_generator_spec.rb, which stubs the private method PreviousRefreshTokenGenerator#no_previous_refresh_token_column? via allow_any_instance_of(...).to receive(:no_previous_refresh_token_column?).

Root cause

It is not a bug in Doorkeeper's generator code, and it never happens when a real user runs rails generate doorkeeper:previous_refresh_token. It is an interaction between RSpec and Thor that only occurs in the spec:

1. allow_any_instance_of(...).to receive(:no_previous_refresh_token_column?) (re)defines that method on the generator class.
2. Defining a method on a Thor class fires Thor::Base.method_added, which registers the (transiently public) method as a runnable command.
3. run_generator → Thor::Group#invoke_all iterates over every registered command and calls Thor::Command#run.
4. By then the stub has the original (private) visibility, so Thor::Command#run hits the private_method?(instance) branch and calls handle_no_command_error, which prints Could not find command "no_previous_refresh_token_column?".

So the trigger is "stub a private method on a Thor generator via allow_any_instance_of". Neither Thor nor RSpec is strictly misbehaving; the test just shouldn't stub the method under test on a Thor class.

Fix

Stub the underlying database dependency that no_previous_refresh_token_column? wraps (ActiveRecord::Base.connection.column_exists?) instead of the private method itself. No method is (re)defined on the generator class, so Thor never registers a spurious command and the noise disappears.

Bonus: the "column already exists" example now stubs column_exists? => true explicitly instead of relying on and_call_original against the test schema, making it deterministic.

Behavior change

None for the generator. Test-only change; the same scenarios are covered:

• column missing → migration generated (with the expected version specifier)
• column already present → no migration generated

Testing

• bundle exec rspec spec/generators/previous_refresh_token_generator_spec.rb
  → 2 examples, 0 failures.
• Full suite: bundle exec rspec → 1295 examples, 0 failures, and the Could not find command "..." line no longer appears anywhere in the output.
• bundle exec rubocop spec/generators/previous_refresh_token_generator_spec.rb
  → no offenses.

[nbulaj]

Cool one, thanks!

[nbulaj]

🙇

[55728]

Thanks a lot 😊