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TypeError: Cannot perform addition with undefined

Just now
# src/components/UserPoints.tsx:42
setPoints(points + newPoints)

Ready to review
- setPoints(points + newPoints)
+ setPoints((prevPoints || 0) + Number(newPoints))

- setPoints((prevPoints || 0) + Number(newPoints))
+ const updatedPoints = Math.min((prevPoints || 0) + Number(newPoints), 100)
+ setPoints(updatedPoints)

Pull Request Merged & Deployed

All tests passing
Code review approved
No regressions detected

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Revise automatically detects errors from your monitoring tools, analyzes the root cause, and creates pull requests with fixes and tests.

Sentry Error Alert 2 minutes ago
NoMethodError: undefined method '[]' for nil:NilClass
app/controllers/api/v1/user_preferences_controller.rb:25:in 'update'
# The error occurred in this code:
def update
  @preferences = current_user.preferences
  @preferences.settings['theme'] = params[:theme]
  @preferences.save!
end
Revise Analysis just now

I've analyzed the error and identified the root cause:

  • The preferences association might be nil
  • Missing initialization of default preferences
  • No error handling for missing preferences

# Proposed fix:

def update
  @preferences = current_user.preferences || current_user.create_preferences
  @preferences.settings ||= {}
  @preferences.settings['theme'] = params[:theme]
  @preferences.save!
end
Pull Request Created just now

fix: Handle nil preferences in UserPreferencesController

Ready to review

This PR:

  • Adds nil checks for preferences
  • Initializes default preferences when missing
  • Includes comprehensive tests
  • Adds error monitoring

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developer123 commented on issue #42

We need to implement a rate limiting feature for our API endpoints. Can Revise help with this?

/revise implement rate limiting for API endpoints using Redis
Revise just now

I'll help implement rate limiting using Redis. Here's my plan:

Create a RateLimiter concern
Add Redis configuration
Implement rate limiting middleware
Add comprehensive tests

# Example implementation:

module RateLimiter
  extend ActiveSupport::Concern

  included do
    before_action :check_rate_limit
  end

  private

  def check_rate_limit
    key = "rate_limit:#{request.ip}"
    count = Redis.current.get(key).to_i

    if count >= max_requests
      render json: { error: 'Rate limit exceeded' }, 
             status: :too_many_requests
    else
      Redis.current.multi do |redis|
        redis.incr(key)
        redis.expire(key, window_seconds)
      end
    end
  end
end

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Analyzing Patterns
Scanning controller patterns
Analyzing error handling
Reviewing test coverage
Detected Patterns
• Service objects for complex operations
• Controller concerns for shared logic
• RSpec shared examples pattern
• Custom error handling middleware
Generated Solution
class Api::V1::BaseController < ApplicationController
  include ErrorHandler
  include RateLimiter
  
  before_action :authenticate_api_user!
  
  rescue_from StandardError do |e|
    handle_error(e)
  end
end

Following your existing patterns for:

  • Error handling structure
  • Authentication flow
  • Controller organization

Test Coverage

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Every code change comes with comprehensive tests, ensuring reliability and preventing regressions across your entire application.

UserProfile.test.tsx
All tests passing
import { render, screen, fireEvent } from '@testing-library/react'
import { UserProfile } from './UserProfile'
import { useUserPreferences } from '@/hooks/useUserPreferences'

jest.mock('@/hooks/useUserPreferences')

describe('UserProfile', () => {
  const mockPreferences = {
    theme: 'light',
    notifications: true,
    updatePreference: jest.fn()
  }

  beforeEach(() => {
    ;(useUserPreferences as jest.Mock).mockReturnValue(mockPreferences)
  })

  it('renders user preferences correctly', () => {
    render()
    expect(screen.getByText('Theme')).toBeInTheDocument()
    expect(screen.getByRole('switch')).toBeInTheDocument()
  })

  it('handles theme toggle correctly', async () => {
    render()
    const themeToggle = screen.getByRole('switch')
    
    await fireEvent.click(themeToggle)
    
    expect(mockPreferences.updatePreference).toHaveBeenCalledWith({
      theme: 'dark'
    })
  })

  it('handles error states gracefully', () => {
    ;(useUserPreferences as jest.Mock).mockReturnValue({
      ...mockPreferences,
      error: new Error('Failed to load')
    })

    render()
    expect(screen.getByText(/error loading/i)).toBeInTheDocument()
  })
})
3 tests completed
Coverage: 100%
✓ renders user preferences correctly
✓ handles theme toggle correctly
✓ handles error states gracefully

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