`Third` Local Lua Debugger for Visual Studio Code

A simple Lua debugger which requires no additional dependencies.

Disclaimer (Third Generation Fork)

This repository represents the "Third" Generation of the Local Lua Debugger. It consolidates years of community developments into a single, modernized codebase.

Consolidation & Modernization

This fork merges the original work by tomblind with significant improvements from Ismoh and several other key contributors.

Key Updates:

Infrastructure: Upgraded to TypeScript 5.x and TSTL 1.34+.
Language Support: Full compatibility with Lua 5.5 (including 64-bit integers and new operators) while maintaining support for Lua 5.1, 5.2, 5.3, 5.4, and LuaJIT.
Zero-Config Injection: The debugger is now globally available via _G.lldebugger when launched through VS Code. Manual require is no longer strictly necessary.
Bug Fixes: Resolved the critical unpack error in TSTL-generated code and improved Windows path handling.

How to use

Depending on your workflow, you can either let the debugger handle everything automatically or manually trigger it within your code.

Method A: Automatic (Recommended)

Simply start your script via the VS Code Debugger. The debugger will automatically inject itself. You can check for its presence in your Lua code:

if lldebugger then
    -- Debugger is active and injected
end

Method B: Manual start

If you prefer manual control or need to start the debugger at a specific point in your execution, use the following snippet:

local hasModule, lld = pcall(require, "lldebugger")
if hasModule then
    lld.start()
end

Code Dependency Graph

The following sources have been integrated into this release:

tomblind/local-lua-debugger-vscode
|-- jan6055/local-lua-debugger-vscode (+1)              Merged (Lua 5.5 Support)
|-- Dobby233Liu/local-lua-debugger-vscode (+6)			Errors-not-merged
|-- Ismoh/local-lua-debugger-vscode (+57)               Merged
|   |-- jurmerlo/local-lua-debugger-vscode (+58)        Merged
|   |-- eduardomezencio/local-lua-debugger-vscode (+49) Merged
|   |-- Vanglant/local-lua-debugger-vscode (+43)        Merged
|   |-- jaymo1011/local-lua-debugger-vscode (+33)       Merged
|   |-- ogsadmin/local-lua-debugger-vscode (+20)        Merged
|   |__ Zorbn/local-lua-debugger-vscode (+19)           Merged
|-- EdMUK/local-lua-debugger-vscode (+7)                Merged
|-- rewqazxv/local-lua-debugger-vscode (+1)             Errors-not-merged
|-- sewbacca/local-lua-debugger-vscode (+2)             Merged
|-- tarantool/tarantool-lua-debugger-vscode (+8)        Errors-not-merged
|   |-- mivallion/tarantool-lua-debugger-vscode (+8)	Errors-not-merged
|   |__ tsafin/tarantool-local-lua-debugger-vscode (+3) Errors-not-merged
|__ B-head/local-lua-debugger-vscode (+16)              Errors-not-merged

Important

The author of this fork makes no claim to the original work. Instead, all contributions from previous authors are fully acknowledged. This fork is solely an attempt to consolidate various improvements and unaddressed pull requests into a functional, up-to-date codebase. You can compare the changes between the original and this fork here. The remainder of this document remains in its original state.

Disclaimer

Forked from tomblind/local-lua-debugger-vscode to maintain the extension, until the main repo will be maintained again.
Disclaimer: I'm not the original author of this extension, I'm just trying to maintaining it.
You can compare the changes between the original and this fork here.

Notice of Breaking Change

Beginning in version 0.3.0, projects which use sourcemaps to debug code transpiled from another language (such as TypescriptToLua), must specify the scriptFiles launch configuration option in order to use breakpoints in the original source files. This allows these to be resolved at startup instead of at runtime which allows for a significant performance increase.

Features

Debug Lua using stand-alone interpretor or a custom executable
Supports Lua versions 5.1, 5.2, 5.3 and LuaJIT
Basic debugging features (stepping, inspecting, breakpoints, etc...)
Conditional breakpoints
Debug coroutines as separate threads
Basic support for source maps, such as those generated by TypescriptToLua

Usage

Lua Stand-Alone Interpreter

To debug a Lua program using a stand-alone interpreter, set lua-local.interpreter in your user or workspace settings:

Alternatively, you can set the interpreter and file to run in launch.json:

{
  "configurations": [
    {
      "type": "lua-local",
      "request": "launch",
      "name": "Debug",
      "program": {
        "lua": "lua5.1",
        "file": "main.lua"
      }
    }
  ]
}

Custom Lua Environment

To debug using a custom Lua executable, you must set up your launch.json with the name/path of the executable and any additional arguments that may be needed.

{
  "configurations": [
    {
      "type": "lua-local",
      "request": "launch",
      "name": "Debug Custom Executable",
      "program": {
        "command": "executable"
      },
      "args": [
        "${workspaceFolder}"
      ]
    }
  ]
}

You must then manually start the debugger in your Lua code:

require("lldebugger").start()

Note that the path to lldebugger will automatically be appended to the LUA_PATH environment variable, so it can be found by Lua.

Requirements & Limitations

The Lua environment must support communication via either stdio or pipes (named pipes on Windows, fifos on Linux).
- Some enviroments may require command line options to support stdio communication (ex. Solar2D requires /no-console flag)
- Use of io.read or other calls that require user input will cause problems in stdio mode. Set program.communication to pipe to work around this.
The Lua environment must be built with the debug library, and no other code should attempt to set debug hooks.
You cannot manually pause debugging while the program is running.
In Lua 5.1 and LuaJIT, the main thread cannot be accessed while stopped inside of a coroutine.

Tips

For convenience, a global reference to the debugger is always stored as lldebugger.
You can detect that the debugger extension is attached by inspecting the environment variable LOCAL_LUA_DEBUGGER_VSCODE. This is useful for conditionally starting the debugger in custom environments.
```
if os.getenv("LOCAL_LUA_DEBUGGER_VSCODE") == "1" then
  require("lldebugger").start()
end
```
Some custom environments will not break on uncaught runtime errors. To catch a runtime error, you can wrap the code with lldebugger.call():
```
lldebugger.call(function()
--code causing runtime error
end)
```
Some environments will not load required files from the standard filesystem. In these cases, you may be able to load the debugger manually using the file path stored in LOCAL_LUA_DEBUGGER_FILEPATH:
```
package.loaded["lldebugger"] = assert(loadfile(os.getenv("LOCAL_LUA_DEBUGGER_FILEPATH")))()
require("lldebugger").start()
```

Additional Configuration Options

`scriptRoots`

A list of alternate paths to find Lua scripts. This is useful for environments like LÖVE, which use custom resolvers to find scripts in other locations than what is in package.config.

`scriptFiles`

A list of glob patterns identifying where to find Lua scripts in the workspace when debugging. This is required for placing breakpoints in sourcemapped files (ex. 'ts' scripts when using TypescriptToLua), as the source files must be looked up ahead of time so that breakpoints can be resolved.

Example: scriptFiles: ["**/*.lua"]

`ignorePatterns`

A list of Lua patterns that specifies files to skip when stepping through code.

Example: ignorePatterns: ["^/usr"]

`stepUnmappedLines`

Step into Lua when stepping through source-mapped code and no mapping is available for the current line.

`breakInCoroutines`

Break into the debugger when errors occur inside coroutines.

Coroutines created with coroutine.wrap will always break, regardless of this option.
In Lua 5.1, this will break where the coroutine was resumed and the message will contain the actual location of the error.

`stopOnEntry`

Automatically break on first line after debug hook is set.

`cwd`

Specify working directory to launch executable in. Default is the project directory.

`args`

List of arguments to pass to Lua script or custom environment when launching.

`env`

Specify environment variables to set when launching executable.

`program.communication`

Specifies how the extension communicates with the debugger.

Possible values:

stdio (default): Messages are embeded in stdin and stdout.
pipe: Pipes are created for passing messages (named pipes on Windows, fifos on Linux). Use this if your environment has issues with stdio communication.

`verbose`

Enable verbose output from debugger. Only useful when trying to identify problems with the debugger itself.

Custom Environment Examples

LÖVE

{
  "version": "0.2.0",
  "configurations": [
    {
      "name": "Debug Love",
      "type": "lua-local",
      "request": "launch",
      "program": {
        "command": "love"
      },
      "args": [
        "game"
      ],
      "scriptRoots": [
        "game"
      ]
    }
  ]
}

if os.getenv("LOCAL_LUA_DEBUGGER_VSCODE") == "1" then
  require("lldebugger").start()
end

function love.load()
  ...

Note that console must be set to false (the default value) in conf.lua, or the debugger will not be able to communicate with the running program.

game/conf.lua

function love.conf(t)
  t.console = false
end

Busted

Note that even when using busted via a lua interpreter, it must be set up as a custom environment to work correctly.

{
  "version": "0.2.0",
  "configurations": [
    {
      "name": "Debug Busted CLI",
      "type": "lua-local",
      "request": "launch",
      "program": {
        "command": "busted"
      },
      "args": [
        "test/start-cli.lua"
      ],
      "ignorePatterns": "^/usr"
    },
    {
      "name": "Debug Busted via Lua Interpreter",
      "type": "lua-local",
      "request": "launch",
      "program": {
        "command": "lua"
      },
      "args": [
        "test/start-interpreter.lua"
      ],
      "ignorePatterns": "^/usr"
    }
  ]
}

test/start-cli.lua

if os.getenv("LOCAL_LUA_DEBUGGER_VSCODE") == "1" then
  require("lldebugger").start()
end

describe("a test", function()
  ...
end)

test/start-interpreter.lua

--busted should be required before hooking debugger to avoid double-hooking
require("busted.runner")()

if os.getenv("LOCAL_LUA_DEBUGGER_VSCODE") == "1" then
  require("lldebugger").start()
end

describe("a test", function()
  ...
end)

Defold

{
  "version": "0.2.0",
  "configurations": [
    {
      "name": "Debug",
      "type": "lua-local",
      "request": "launch",
      "program": {
        "command": "dmengine"
      },
      "args": ["./build/default/game.projectc"],
      "scriptRoots": ["."] // Required for debugger to find scripts
    }
  ]
}

if os.getenv("LOCAL_LUA_DEBUGGER_VSCODE") == "1" then
  local lldebugger = loadfile(os.getenv("LOCAL_LUA_DEBUGGER_FILEPATH"))()
  lldebugger.start()
end

function init(self)
  ...
end

Information on downloading dmengine for your platform can be found here.

Solar2D / Corona

{
  "version": "0.2.0",
  "configurations": [
    {
      "name": "Debug",
      "type": "lua-local",
      "request": "launch",
      "windows": {
        "program": {
          "command": "C:\\Program Files (x86)\\Corona Labs\\Corona\\Corona Simulator.exe",
        },
        "args": [
          "/no-console",
          "/debug",
          "${workspaceFolder}\\main.lua"
        ]
      },
      "osx": {
        "program": {
          "command": "/Applications/Corona/CoronaSimulator.app/Contents/MacOS/CoronaSimulator",
        },
        "args": [
          "-no-console"
          "YES"
          "-debug"
          "1"
          "-project"
          "${workspaceFolder}/main.lua"
        ]
      }
    }
  ]
}

if os.getenv("LOCAL_LUA_DEBUGGER_VSCODE") == "1" then
  local lldebugger = loadfile(os.getenv("LOCAL_LUA_DEBUGGER_FILEPATH"))()
  lldebugger.start()
end

...

TypescriptToLua (Custom Environment)

{
  "version": "0.2.0",
  "configurations": [
    {
      "name": "Debug TSTL",
      "type": "lua-local",
      "request": "launch",
      "program": {
        "command": "my_custom_environment"
      },
      "args": [
        ...
      ],
      "scriptFiles": ["**/*.lua"] // Required for breakpoints in ts files to work
    }
  ]
}

if os.getenv("LOCAL_LUA_DEBUGGER_VSCODE") == "1" then
  require("lldebugger").start()
end

...

tsconfig.json

{
  "compilerOptions": {
    "sourceMap": true,
    ...
  },
  "tstl": {
    "noResolvePaths": ["lldebugger"] // Required so TSTL ignores the missing dependency
  }
}

Name		Name	Last commit message	Last commit date
Latest commit History 322 Commits
.github/workflows		.github/workflows
.vscode		.vscode
debugger		debugger
extension		extension
resources		resources
tests		tests
.gitattributes		.gitattributes
.gitignore		.gitignore
.vscodeignore		.vscodeignore
CHANGELOG.md		CHANGELOG.md
LICENSE		LICENSE
README.md		README.md
package-lock.json		package-lock.json
package.json		package.json

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Third Local Lua Debugger for Visual Studio Code

Disclaimer (Third Generation Fork)

Consolidation & Modernization

How to use

Method A: Automatic (Recommended)

Method B: Manual start

Code Dependency Graph

Disclaimer

Notice of Breaking Change

Features

Usage

Lua Stand-Alone Interpreter

Custom Lua Environment

Requirements & Limitations

Tips

Additional Configuration Options

scriptRoots

scriptFiles

ignorePatterns

stepUnmappedLines

breakInCoroutines

stopOnEntry

cwd

args

env

program.communication

verbose

Custom Environment Examples

LÖVE

Busted

Defold

Solar2D / Corona

TypescriptToLua (Custom Environment)

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`Third` Local Lua Debugger for Visual Studio Code

`scriptRoots`

`scriptFiles`

`ignorePatterns`

`stepUnmappedLines`

`breakInCoroutines`

`stopOnEntry`

`cwd`

`args`

`env`

`program.communication`

`verbose`

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