ddless-engine

The PHP runtime engine behind DDLess — a visual step-through debugger for PHP.

This repo contains the engine only. The desktop app, UI, and AI Copilot are available at ddless.com.

What it does

ddless-engine parses PHP source via AST (nikic/PHP-Parser), injects ddless_step_check() calls before each executable line using a custom stream wrapper, and communicates with the desktop app through file-based IPC. Your original files are never modified on disk.

Supports breakpoints (conditional, logpoints, dumppoints), step-in/over/out, watch expressions, variable inspection, trace mode, and timeframe (record every executed line, then replay to any point).

Frameworks

CakePHP · CodeIgniter 4 · Drupal · Laravel · Slim 4 · Symfony · Tempest · Vanilla PHP · WordPress · Yii2

Project layout

src/
├── debug.php                Core engine (AST analysis, instrumentation, breakpoint handler)
├── http_trigger.php         Entry point for HTTP debug sessions
├── method_trigger.php       Entry point for method-level debugging
├── cli_trigger.php          Entry point for CLI script debugging
├── task_trigger.php         Entry point for task/command debugging
├── ssh_proxy_router.php     SSH remote debugging support
├── frameworks/              Framework-specific request handling and bootstrapping
│   ├── cakephp/
│   ├── codeigniter/
│   ├── drupal/
│   ├── laravel/
│   ├── php/
│   ├── slim/
│   ├── symfony/
│   ├── tempest/
│   ├── wordpress/
│   └── yii2/
├── playground/              Terminal debugger to exercise the engine without the desktop app
├── sessions/                File-based IPC (runtime ↔ desktop app) — created at runtime, git-ignored
├── cache/                   Pre-instrumented code cache — created at runtime, git-ignored
└── vendor-internal/         Bundled PHP-Parser (no Composer required)

Try it

No desktop app and no project needed — a bare clone is enough:

php src/playground/test_trigger.php --code '$x = 1; $y = 2; echo $x + $y;' --bp 1

It pauses on the line and shows a prompt: c continue, n next, s step in, o step out, v variables, q quit.

The playground also drives the method executor, the task runner and the HTTP pipeline of each framework. See CONTRIBUTING.md and src/playground/README.md.

Requirements

• PHP 7.4+ (tested up to 8.5)
• json extension (ships with PHP by default)
• No external dependencies

Tests

php tests/run-all.php

Or run individually:

php tests/NormalizeValueTest.php
php tests/InstrumentCodeAstTest.php
php tests/HttpRequestTest.php

CI runs against PHP 7.4+ on every push and PR.

License

Source-available. See LICENSE.