commentary.md

My theory is that folks are hallucinating complex structure for these docs. If you read the Cursor forums, people are asking the Cursor LLM how to format them 🙃 Those shared above are the results of writing in the UI and what gets puts into version control.

My approach is that when I am annoyed by something I have to manually fix up, I go update the file.

Some of it is just impossible, like using the new Strong Params expects syntax given the training cutoffs. I’m not going to completely document the interface (cursor/rules can’t link to docs and can only link to a single file) . So I hint it, and it simply hallucinates the interface mostly correctly most of the time. Principle of Least Surprise in practice!

My .cursorrules were pretty inconsistent project to project, and I don’t believe that putting very generic things like “Use exceptions for exceptional cases, not for control flow” or “Use Active Record effectively” improves things.

controllers.mdc

---
description: Changes to Rails Controllers
globs: app/controllers/*
alwaysApply: false
---
# When modifying Rails controllers

## Routes

When adding new controllers or actions, don't forget to update the [routes.rb](mdc:config/routes.rb) 

## Strong Params

Use `expect` syntax instead of `require`/`allow`

```
# Bad 
params.require(:user).permit(:name, :favorite_pie)

# Good
params.expect(user: [:name, :favorite_pie])
```

## Wizard flows

Controllers in the `Apply` namespace are part of a form wizard. Each controller represents a stage in the from wizard flow. The flow is implemented in [flowable.rb](mdc:app/controllers/concerns/flowable.rb) and the stages are declared in [base_controller.rb](mdc:app/controllers/apply/base_controller.rb). To redirect to the next stage of the flow, use `flow_next_path`. 

## Same-controller paths and redirects

When linking or redirecting to an action in the same controller, always use `url_for(action: "the_action")` with implicit controller instead of a path helper:

```
#  Bad
my_controller_the_action_path

# Good
url_for(action: "the_action")
```

migrations.mdc

---
description: Rules for migrations
globs: db/*
alwaysApply: false
---
# Database migration rules

- The database is Postgres
- Use `text` for all string fields; never use `string` or `varchar`
- Use `datetime` instead of `timestamp`
- Assume that Boolean values should be nullable unless specified 

tests.mdc

---
description: RSpec testing rules
globs: spec/*
alwaysApply: false
---
# Rules for writing RSpec tests

- Write comprehensive tests using RSpec. It's ok to put multiple assertions in the same example.
- Use factories (FactoryBot) for test data generation.
- When writing System Tests. Use `css_id(*)` and `css_class(*)` instead of `"#{dom_id(*)}"` `"#{dom_class(*)}"`
- `shoulda-matchers` is not installed. Don't test declarative configuration. For validations, only test that it's not valid when the validation is violated.
- `rails-controller-testing` is not installed. Test controllers behaviorally: correct status code and/or model changes. Don't use `assigns` to inspect ivars.