Wheels Debugging

Common Errors

"No matching function [RENDERPAGE] found"

Cause: Using wrong function name - CFWheels uses renderView() not renderPage()

Solution: Change to correct function name

❌ renderPage(action="new")
✅ renderView(action="new")

"Missing argument name" Error

Cause: Mixed positional and named arguments

Solution: Use consistent argument style

❌ hasMany("comments", dependent="delete")
✅ hasMany(name="comments", dependent="delete")

❌ .resources("sessions", only="new,create")
✅ .resources(name="sessions", only="new,create")

"key [onCreate,onUpdate] doesn't exist"

Cause: Using comma-separated values in validation when parameter

Solution: Remove the when parameter - validations run on both create and update by default

❌ validatesConfirmationOf(properties="password", when="onCreate,onUpdate")
✅ validatesConfirmationOf(properties="password")

"Can't cast Object type [Query] to [Array]"

Cause: Using Array functions on queries

Solution: Use query methods

❌ ArrayLen(post.comments())
✅ post.comments().recordCount

"Association not found" Error

Cause: Association not properly defined or typo

Solution: 1. Check model config() for association definition 2. Verify association name matches 3. Check model name spelling

"Table not found" Error

Cause: Migration not run or table name mismatch

Solution:

wheels dbmigrate latest

"Column not found" Error

Cause: Property doesn't exist in database

Solution: 1. Add column via migration 2. Check property name spelling 3. Verify case sensitivity

Debugging Tools

Enable Debug Output

// In config/settings.cfm
set(showDebugInformation=true);
set(showErrorInformation=true);

Inspect Variables

<cfdump var="#post#" label="Post Object">
<cfabort>

Check SQL Queries

// Wheels logs all SQL to debugging output
// Look for red SQL queries (errors)

Browser Testing for Debugging

When debugging UI/view issues, use browser MCP tools to verify:

Check Page Rendering

// Use available MCP tool (in order of preference):

// Option 1: Puppeteer MCP (preferred)
mcp__puppeteer__puppeteer_navigate(url="http://localhost:PORT/controller/action")
mcp__puppeteer__puppeteer_screenshot(name="debug-screenshot")

// Option 2: Playwright MCP
mcp__playwright__playwright_navigate(url="http://localhost:PORT/controller/action")
mcp__playwright__playwright_screenshot()

// Option 3: Browser MCP (fallback)
mcp__browsermcp__browser_navigate(url="http://localhost:PORT/controller/action")
mcp__browsermcp__browser_screenshot()

Verify Form Submissions

// Navigate to form
mcp__puppeteer__puppeteer_navigate(url="http://localhost:PORT/posts/new")

// Fill and submit
mcp__puppeteer__puppeteer_click(selector="input[name='post[title]']")
// Check for errors in response

Check for JavaScript Errors

Use browser console output to identify client-side issues that might affect form submissions or dynamic content.

Generated by: Wheels Debugging Skill v1.1