# bugstack for Ruby & Rails

Ruby · Rails

# bugstack for Ruby & Rails

Auto-fix NoMethodError nil:NilClass, ActiveRecord::RecordNotFound, and nil-related errors in Rails.

## What Ruby Errors bugstack Fixes

-   **NoMethodError: undefined method for nil:NilClass** — calling methods on nil objects
-   **ActiveRecord::RecordNotFound** — querying for records that don't exist
-   **ArgumentError: wrong number of arguments** — method arity mismatches
-   **NameError: uninitialized constant** — referencing undefined classes or modules

## Install the SDK

Add bugstack to your Gemfile:

```
gem install bugstack
```

Or add it to your Gemfile and bundle:

```
# Gemfile
gem 'bugstack'
```

```
bundle install
```

Then initialize it in an initializer:

```
# config/initializers/bugstack.rb
Bugstack.configure do |config|
  config.api_key = ENV["BUGSTACK_API_KEY"]
end
```

## Example Fix

bugstack detects a NoMethodError caused by calling a method on nil and writes a surgical fix:

Before (broken)

```
def show
  @user = User.find_by(id: params[:id])
  @email = @user.email
end

# Runtime error when user is nil:
# NoMethodError: undefined method
#   'email' for nil:NilClass
```

After (fixed by bugstack)

```
def show
  @user = User.find_by(id: params[:id])
  if @user.nil?
    head :not_found
    return
  end
  @email = @user.email
end
```

## Related Error Guides

-   [Fix ActiveRecord::RecordNotFound in Rails](/errors/activerecord-not-found-rails)
-   [Fix ArgumentError: wrong number of arguments in Rails](/errors/argumenterror-wrong-args-rails)
-   [Fix NoMethodError for nil:NilClass in Rails](/errors/nomethoderror-nil-rails)
-   [Fix ActionController::RoutingError in Rails](/errors/rails-routing-error)

[Full installation guide with config reference →](/docs/installation/ruby)

## Stop fixing Ruby errors manually

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