Documentation
Advanced Topics
Troubleshooting

Troubleshooting

Common issues and their solutions.

Script Loading Issues

Script Not Found (404)

Symptoms: goto shows “404 Not Found” or blank screen

Causes:

  • Script file doesn’t exist at the specified path
  • Incorrect URL
  • Network path not accessible

Solutions:

  1. Verify the file exists in the local goto directory
  2. Check the URL matches the file path exactly
  3. Ensure network drive is mounted (Windows: check S: drive)
  4. Check file permissions
# Linux: Check if network share is mounted
df -h | grep /mnt/s-drive

# Windows: Check S: drive in File Explorer

Blank Screen / No Content

Symptoms: goto opens but shows nothing

Causes:

  • Script doesn’t call window.SetContent()
  • Script has errors before reaching window.SetContent()
  • Widget creation failed

Solutions:

  1. Ensure script calls window.SetContent():
content := widget.NewLabel("Hello")
window.SetContent(content)  // Don't forget this!
  1. Check for errors in script logic
  2. Test with minimal script first

Runtime Errors

Variable Not Defined

Error: undefined variable: myVar

Cause: Variable used before declaration

Solution:

// Wrong
print(myVar)
myVar := "value"

// Correct
myVar := "value"
print(myVar)

Nil Pointer / Null Reference

Error: Accessing properties of nil object

Cause: Object is nil/undefined

Solution:

// Check before use
if data != nil {
    print(data.field)
}

// Or use default
value := ""
if data != nil {
    value = data.field
}

Type Errors

Error: Type mismatch or conversion error

Solution:

// Convert types explicitly
numStr := "123"
num := int(numStr)  // Convert string to int

// For database IDs
id := string(row["id"])  // Convert to string

Database Issues

Connection Failed

Symptoms: SQL connection errors

Solutions:

  1. Verify connection string:
conn := sql.connect(
    "sqlserver://username:password@server:1433/database",
    {"stream": true}
)
  1. Check credentials in config file
  2. Verify network access to database server
  3. Test with SQL Server Management Studio first

Query Returns No Data

Causes:

  • Incorrect SQL syntax
  • No matching records
  • Wrong table/column names

Solutions:

  1. Test query in SQL client first
  2. Add error handling:
rows := conn.query("SELECT * FROM MyTable")
if len(rows) == 0 {
    window.SetStatus("No results found")
    return
}
  1. Print query for debugging:
query := "SELECT * FROM Table WHERE id = " + string(id)
print(query)  // Check the actual query
rows := conn.query(query)

API Integration Issues

Fetch Fails / Timeout

Symptoms: API requests fail or timeout

Solutions:

  1. Check URL is correct:
url := "https://api.example.com/data"
print("Fetching:", url)  // Verify URL
response := fetch(url)
  1. Handle network errors:
response := fetch(url)
if response.status != 200 {
    window.SetStatus("API Error: " + string(response.status))
    return
}
  1. Increase timeout if needed
  2. Check proxy settings if behind corporate firewall

JSON Parse Error

Symptoms: .json() fails or returns unexpected data

Solutions:

  1. Check response format:
response := fetch(url)
print("Response:", response.text)  // See raw response
data := response.json()
  1. Verify API returns JSON
  2. Handle parse errors:
if response.headers["Content-Type"] != "application/json" {
    window.SetStatus("Error: Expected JSON response")
    return
}

Table Widget Issues

Table Not Showing Data

Causes:

  • Forgot to call table.Refresh()
  • Data callbacks not returning correct format
  • RowCount returns 0

Solutions:

table := widget.NewTable("data", 20)

// Set callbacks
table.Columns(func() {
    return ["Col1", "Col2"]
})

table.RowCount(func() {
    count := len(data)
    print("Row count:", count)  // Debug
    return count
})

table.Data(func(offset, limit) {
    print("Fetching rows:", offset, "to", limit)  // Debug
    return data[offset:limit]
})

table.Refresh()  // DON'T FORGET THIS!

Table Pagination Not Working

Cause: Incorrect offset/limit handling

Solution:

table.Data(func(offset, limit) {
    // Handle edge case
    if offset >= len(data) {
        return []
    }

    end := offset + limit
    if end > len(data) {
        end = len(data)
    }

    return data[offset:end]
})

Performance Issues

Slow Loading

Causes:

  • Loading too much data at once
  • Inefficient queries
  • No pagination

Solutions:

  1. Use pagination:
// Good: Server-side pagination
query := "SELECT * FROM data OFFSET " + string(offset) +
         " ROWS FETCH NEXT " + string(limit) + " ROWS ONLY"

// Bad: Load everything
query := "SELECT * FROM data"  // Could be millions of rows!
  1. Add loading indicator:
window.SetStatus("Loading...")
data := fetchData()
window.SetStatus("Ready")

UI Freezing

Cause: Long-running operations block UI

Solution: Provide feedback and break up operations:

window.SetStatus("Processing... (this may take a moment)")

// Process in batches
for i, item := range items {
    processItem(item)

    // Update progress
    if i % 100 == 0 {
        window.SetStatus("Processing... " + string(i) + "/" + string(len(items)))
    }
}

File Operations

File Not Found

Solution:

path := txtPath.Text

if !os.exists(path) {
    window.SetStatus("Error: File not found: " + path)
    return
}

data := os.read_file(path)

Permission Denied

Causes:

  • No read/write permission
  • File is locked by another process

Solutions:

  1. Check file permissions
  2. Close file in other applications
  3. Run goto with appropriate permissions

Cross-Platform Issues

Path Separators

Problem: Hard-coded paths don’t work on all platforms

Solution:

// Use filepath.join
path := filepath.join(["data", "files", "input.txt"])

// Or check OS
if gui.GOOS == "windows" {
    path := "S:\\data\\file.txt"
} else {
    path := "/mnt/s-drive/data/file.txt"
}

Line Endings

Problem: Windows files have \r\n, Unix has \n

Solution:

// Normalize line endings
data := os.read_file(path)
text := string(data)
text = strings.replace_all(text, "\r\n", "\n")
lines := strings.split(text, "\n")

Debugging Tips

Add Debug Output 

// Print variables
print("Debug: value =", myVar)

// Print JSON for complex objects
print("Debug: data =", json.generate(data))

// Use status bar
window.SetStatus("Debug checkpoint 1")

Simplify to Isolate Issue

Start with minimal working code:

// Step 1: Just show content
window.SetContent(widget.NewLabel("Test"))

// Step 2: Add one feature
// Step 3: Add another feature
// ...until you find what breaks

Check Browser Console

For web-related issues, check browser console (F12) when using gui.OpenBrowser().

Getting Help

If you’re still stuck:

  1. Check this documentation
  2. Review examples for similar functionality
  3. Test with simpler code to isolate the issue
  4. Contact the goto development team
  5. Check GitLab issues: https://brabgit.global.iff.com/brablab/goto/issues

Common Error Messages

Error Meaning Solution
undefined variable Variable not declared Declare variable before use
type error Wrong data type Convert types explicitly
nil pointer Accessing nil object Check for nil before access
index out of range Array index invalid Check array length
connection refused Can’t reach server Check network/credentials
syntax error Invalid Risor syntax Check script syntax
Best Practices