# Zoom Test Bug Fix

## Issue Summary

**Bug**: The `web_zoom_test_cremotemcp` tool was failing with JSON parsing errors:
```
Error: invalid character 'm' looking for beginning of value
```

**Root Cause**: Unreachable code in the JavaScript evaluation function in `daemon/daemon.go` at line 9375.

## Technical Details

### The Problem

In the `testZoom` function in `daemon/daemon.go` (lines 9312-9376), the JavaScript code had a duplicate return statement:

```javascript
return {
    viewport_width: window.innerWidth,
    viewport_height: window.innerHeight,
    has_horizontal_scroll: hasHorizontalScroll,
    content_width: contentWidth,
    content_height: contentHeight,
    visible_elements: visibleCount,
    overflowing_elements: overflowingCount,
    text_readable: textReadable,
    min_font_size: minFontSize
};
return JSON.stringify(result);  // ← UNREACHABLE CODE - BUG
```

The second `return JSON.stringify(result);` statement was:
1. **Unreachable** - came after a valid return statement
2. **Referenced undefined variable** - `result` doesn't exist in that scope
3. **Caused malformed output** - the JavaScript engine likely returned undefined or threw an error

This resulted in the Go code receiving malformed data that couldn't be parsed as JSON, causing the error message about invalid character 'm'.

### The Fix

**File**: `daemon/daemon.go`  
**Line**: 9375 (removed)

Removed the unreachable `return JSON.stringify(result);` statement. The JavaScript now correctly returns the object directly, which the Go code can properly parse.

### Fixed Code

```javascript
return {
    viewport_width: window.innerWidth,
    viewport_height: window.innerHeight,
    has_horizontal_scroll: hasHorizontalScroll,
    content_width: contentWidth,
    content_height: contentHeight,
    visible_elements: visibleCount,
    overflowing_elements: overflowingCount,
    text_readable: textReadable,
    min_font_size: minFontSize
};
// Removed: return JSON.stringify(result);
```

## Testing

### Build Verification
```bash
cd mcp && go build -o cremote-mcp
```
✅ Build successful - no compilation errors

### Binary Created
```
-rwxrwxr-x 1 squash squash 9.8M Oct  2 13:04 cremote-mcp
```

## Impact

This fix resolves the zoom test functionality, which is critical for WCAG 1.4.4 and 1.4.10 compliance testing:
- **WCAG 1.4.4**: Resize text - Users must be able to zoom text to 200% without loss of content or functionality
- **WCAG 1.4.10**: Reflow - Content must reflow at 400% zoom without horizontal scrolling

## Next Steps

1. **Deploy** the updated MCP binary to the container
2. **Restart** the cremote daemon to load the new binary
3. **Resume** the ADA Level AA assessment of https://visionleadership.org
4. **Verify** zoom test now works correctly at 100%, 200%, and 400% zoom levels

## Related Files

- `daemon/daemon.go` - Main fix location (line 9375 removed)
- `mcp/main.go` - MCP server tool registration (lines 3793-3890)
- `client/client.go` - Client-side zoom test interface (lines 3599-3648)

## Commit Message Suggestion

```
fix: Remove unreachable return statement in zoom test JavaScript

The testZoom function had an unreachable `return JSON.stringify(result);`
statement after the main return, causing JSON parsing errors. This resulted
in "invalid character 'm' looking for beginning of value" errors when
attempting to parse the zoom test results.

Fixes zoom test functionality for WCAG 1.4.4 and 1.4.10 compliance testing.

File: daemon/daemon.go, line 9375
```

