Thanks a lot for this great tool!
Until now I haven't been able to figure out how to do variable assignment e.g. a=5 in the debugger environment. Is this a valid functionality?

I want to run a previous command (e.g., p some_tablex[2]) without typing it again, I just pressed the up arrow from the keyboard and hoped the above commands would be copied automatically. However, it didn't work. It would be very helpful to add this function, as every time typing in everything is quite tedious.

It can detect a breakpoint in the main file, but cannot detect it in other files of the same project.

Would be nice if w(here) could be automatically called at each prompt

I am on Ubuntu 18.04 using lua 5.2.4.

While running the tutorial.lua file, the following output occurred (skipping the beginning):

    Now try the 'n' command.
    (n = step to the Next line in the source code)

tutorial.lua:85 in 'tutorial.lua:0'
debugger.lua> n
tutorial.lua:60 in 'func2'
debugger.lua> n
You used the 'n' command.
tutorial.lua:61 in 'func2'
debugger.lua> n
So it's skipping over the lines in func2().
tutorial.lua:65 in 'func2'
debugger.lua> n
tutorial.lua:67 in 'func2'
debugger.lua> n
tutorial.lua:64 in 'f'
debugger.lua> n
... and anything it might call.

But of course, I expected:

    Now try the 'n' command.
    (n = step to the Next line in the source code)

./tutorial.lua:85 in '<./tutorial.lua:0>'
debugger.lua> n
You used the 'n' command.
So it's skipping over the lines in func2().
... and anything it might call.

Thus, it seems like n steps into functions just like s does. Likewise, using f inside a function simply did the same as c instead of stopping right after the function.

I assumed n, f worked in the past, so I used git bisect and found that 4cc1189 introduced this error (n, f worked fine before 4cc1189).

In particular, this line (line 142 in 4cc1189):
return info.source:match('^@[%.%/]') ~= nil
matches only files starting with ./

Then I noticed, that n, f work properly if I run the tutorial with

lua ./tutorial.lua

but not with

lua tutorial.lua

Because the latter does not contain ./ and aforementioned line of code does not find a match.

Maybe the pattern '^@[%.%/]' needs to be adapted? Or is the prefix './' always required?

cannot resolve symbol 'isatty': Procedure not found

Let's say I moved up the stack by a frame. Now, I want to skip to the (n)ext line of the frame I'm inspecting. The current behavior simply skips the line of the bottom frame (even if I moved up a frame).

Would this be easy to implement? 😄

From an email:

Thanks for writing the Lua debugger. I use it in my control program for my model
trains.

It was trivial to install and by overwriting the dbg.* functions, I was able to seamless
integrate it into my program.

I did come across one odd behavior. I had this function in my code:

   function cleanup(Engine, TIU)
            -- this function is called once when the user presses the [STOP] button
            --print(os.date("cleanup()  %d %b %Y   %X"));
            return true;            -- false=cleanup failed, true=cleanup succeeded
   end

A commented out "print()" command that I had for testing only.

I entered the debugger with "dbg()" and then used the "s(tep)" command
to step into this function and through it.As I stepped through lines
68 an then line 69 I got this error message:

68 -- this function is called once when the user presses the [STOP] button
Error 2 running function cleanup() : E:\Projects\RTC\lua\debugger.lua:110: bad argument #3 to 'format' (no value)

Here is the dbg_writeln() in debugger.lua that I overwrote (I don't need the "\n"):

   local function dbg_writeln(str, ...)
      if select("#", ...) == 0 then
            -- mcd change for RTC Debugging
            --dbg.write((str or "<NULL>").."\n")
            dbg.write((str or "<NULL>"))
            -- mcd change for RTC Debugging
      else
            -- mcd change for RTC Debugging
            --dbg.write(string.format(str.."\n", ...))
            dbg.write(string.format(str, ...))                      ------- this is line 110 refered to in the error       
            -- mcd change for RTC Debugging
      end
   end

I appears that the "%" in the commented out print() statement is confusing
the string.format() call inside of dbg_writeln().

I set "dbg.auto_where = 2" for the line tracing.

This can be worked around but you might want to fix it.

Thanks again, Mark

Sometimes I want to reuse something I typed before. How hard would it be to add command history? Should I look around for another Lua script that does it, and send it your way?

^[[A (up arrow) goes to the next older command (if one exists)

^[[B (down arrow) goes to the next newer command, where an empty line is always last

History would persist across debugger sessions.

Whether it can be directly picked to a line？

This is something I could probably work on with the time I have available. The low hanging fruit is to at least automate the tutorial as a test. Maybe start some simple unit tests beyond that.

The ability to effectively edit the current command would be great. Here are the key bindings:

^[[D (left arrow): move the caret one character to the left, unless at the beginning

^[[C (right arrow): move the caret one character to the right, unless at the end

^A: move the caret to the beginning

^E: move the caret to the end

Sorry I haven't been super active with helping to test. :-\

Stepping through the tutorial is currently broken. For example, if you check out 2df69^, follow the tutorial, all seems to be well. 2df69 doesn't work for me any more on lua 5.3.1 or luajit 2.0.3, and gives different behaviors. I also tried 5.3.3 on a different machine and got the same 5.3.1 behavior.

Should we revert the commit for now or do you think you have a pretty good idea of what is wrong? (Sorry, it looks like you put a lot of work into that one. :-\ )

It would be great if using finish or next within a coroutine would avoid triggering the REPL outside that coroutine (unless the coroutine dies). You can always use step if you want to follow yields.

A shortcut for p os.exit() would be appreciated.

^C may be a good option if you can capture keyboard input.

^D seems to exit the debugger, which works great.

Is it possible to debug functions created with loadstring?

Probably this debugger was not even meant to work with love2d, but I'm reporting here because it would be great to be able to get it working there!

When running dbg(), I get the Loaded for LuaJIT 2.0.5 message in the terminal and after that the program keeps running instead of the debugger kicking in. Also, the program runs with very poor performance after this, as if it's doing something in the background.

Edit: forgot to mention love version: 11.1

Hello.

Currently, debugger.lua uses it's own "recurse" function which gets pretty good results, but if I use metaclass, it defines a "__tostring" meta-method which results in this being printed out:

debugger.lua> p self.tileMap
self.tileMap => instance of class TileMap

However, if I swap "recurse" with my own "print" function, I can get something like this

debugger.lua> p self.tileMap
self.tileMap => <TileMap>{
  layers = {
    Above = <TileMapLayer>{
      tiles = {},
      z = 1
    },
    Below = <TileMapLayer>{
      tiles = {
        ["0,0"] = <Tile>{
          id = 0,
          tid = 4
        },
        ...
      },
      z = 0
    },
    Collision = <TileMapLayer>{
      tiles = {},
      z = -1
    }
  },
  tilesets = {
    [4] = <Tileset>{
      texture = sol.::LuaTexture: 0x555ad6cb0878
    }
  }
}

So, it would be pretty nice if dbg has a configurable "prettyPrint" function, which you could override. :)
If you're OK with the idea, I can make a PR.

first of all my congratulations on the project, I tested it here, and it worked which is a beauty.

I would like to suggest some modifications like:

colors:

• in addition to the environment variable uses or a init function;
• defines a background color by default black / gray is not 'too visible'

...
_G.DBG_NOCOLOR = true;
dbg = dofile('debugger.lua')
dbg.init( {'color' = false} )
...

accept callback:

• dbg.read(prompt)
• dbg.write(str)

I come from a Ruby background and am used to pry and byebug as my main debuggers, and spent a good 20mins wondering why I couldn't inspect variables with this debugger when stepping/moving worked fine.

I was doing variations of this:

debugger.lua> transitions
debugger.lua> src_state
debugger.lua> print src_state
debugger.lua> locals
debugger.lua> l
	dest_state => "Ready"
	src_state => "Not Ready"
	transitions => {"Not Ready" = {}}

I realize that l prints all the locals out, but I'm wondering how I can inspect individual variables...

And then out of frustration I type in:

debugger.lua> asdfasdf
debugger.lua>

And notice that the prompt doesn't react and then I'm like ohhh when it doesn't understand a command it just pretends like nothing happened.

Cue these attempts:

debugger.lua> pp(transitions)
debugger.lua> p
Error: command 'p' not recognized.
Type 'h' and press return for a command list.
debugger.lua> pp
debugger.lua> h
[.. help output ..]
debugger.lua> p transitions
transitions => {"Not Ready" = {}}

I was expecting the output of p and pp to tell me what arguments they were expecting.

Even more confusing is that when you do type in the right single character command but with the wrong arguments, it says Error: command 'p' not recognized - which is arguably even more misleading 🤣

Anyway. Just throwing my 2 cents in here. I'm still too much of a lua noob to attempt to fix this myself, but if you think it's a worthy addition, I can make an attempt.

Edit: Turned out to be an easy fix - I created a PR.

in file debugger.c.lua, line 108

bool err = lua_pcall(lua, nargs, nresults, msgh);

'bool' must be replace by 'int', otherwise some errors are missed

This bug is not related to your code but maybe you know how to fix it.

It happens on Xubuntu 20.04, xfce4-terminal, on any lua version (5.1-5.4), including luajit.

In debugger.lua prompt I can't use arrow keys. When I press them, it types annoying bullshit like this: "^[[D^[[A^[[C^[[B".

dbg.read will always exists as its defined on 85 line and then put on 511 line

Windows 10 anniversary update added ENABLE_VIRTUAL_TERMINAL_PROCESSING flag to console mode, which can be used to enable ANSI color codes. This can be enabled for LuaJIT environment (where FFI is available). Below is my way to enable it.

https://github.com/MikuAuahDark/livesim2/blob/master/logging.lua#L59-L63

I have tried to run the debugger at the entry of a function with the given name, using the following (slow) code. This works with debug.debug() but not with dbg(). Is there a recommended way to do this? Note that calling dbg() within debug.debug() does not work either (assuming dbg() is visible).

local dbg = require 'debugger'
local function dbgfun (fun, typ_)
  local function hook (event)
    local info = debug.getinfo(2,'n')
    if info.name == fun then
      io.write("dbg: ", info.name, "\n")
      return debug.debug() -- tail call
--    return dbg()         -- tail call
    end
  end
  debug.sethook(hook, typ_ or "call")
end
dbgfun("myfun")

does not work on windows because of

local cwd = '^' .. os.getenv('PWD') .. '/'

"unable to concatenate nil value"

Does this debugger work on windows 10. I'm currently running win 10 with luajit. I get the following error message.

Error: lib/debugger.lua:448: cannot resolve symbol 'isatty': The specified procedure could not be found.

stack traceback:
[C]: in function '__index'
lib/debugger.lua:448: in main chunk
[C]: in function 'require'

backend

When inspecting a table, it sometimes has a property whose value is a long string that fills up the terminal. This is often too noisy. If I wanted to see the entire string, I would inspect that specific property.

Truncation would replace the end of the string with ... (# = 1000). This could be colored so it's clear this isn't the string's real value.

What would be a good length for truncation?

I get this error PANIC: unprotected error in call to Lua API (attempt to index a function value) inside function dbg_setup() when setting readFunct param, inside function lua_setfield(lua, -1, "read");

Hi, could you choose and publish a license for this project? I want to use it in my game, but our packaging requirements require that all files have an explicit license from the author.

If you don't particularly care, I'd suggest the MIT license since it's compatible with nearly every organization's licensing requirements.

Great work on the library, hope to get a response soon.

after i curl my request, script just stop run, and no entry to debug

Luarocks seems to have this package: https://luarocks.org/modules/3scale/debugger

Are you the uploader?

Some command for viewing the keys of a table would be very useful.

A nice feature would be linenoise autocomplete for table keys.

We just need a function that uses pairs on the table and its __index chain (assuming all __index values are tables).

A method that sets a debug hook that triggers the REPL on any uncaught errors would be useful, because you wouldn't have to reactively edit a dbg.call into your code when an unexpected error occurs.

Not decided on the method name, but I think this would be pretty cool! 👍