show error in logs when sourceMaps are set incorrectly

[jpeletier]

Thank you for this project, it is a hidden gem. I have just found about it and now I can debug my Lua code!

This PR is a small fix so that variables are shown in the VSCode debugger VARIABLES window when debugging a LuaJIT target.

The following error was shown in the logs:

[ERROR]ERROR:...lua-debug-2.0.12-linux-x64/script/backend/worker/variables.lua:142: attempt to compare number with nil

rdebug.getinfo(frameId, "r", info) is not implemented for LuaJIT, so ftransfer and ntransfer are not populated.

With this fix I can now inspect all the variables, globals and upvalues!

[actboy168]

Why did you arrive here? This function should only be executed by Lua5.4.

lua-debug/extension/script/backend/worker/variables.lua

Lines 1319 to 1321 in 070cf2a

	if LUAVERSION >= 54 then
	varCreateScopes(frameId, scopes, "Return", false)
	end

[jpeletier]

Thank you for the clue. I found the issue.
The problem is for some reason my sourceMaps configuration, which should be an array of pairs, was improperly configured:

			"sourceMaps": [
				[	 
					"${workspaceFolder}/*"
				]
			],

This made the code in

lua-debug/extension/script/backend/worker/source.lua

Lines 31 to 38 in 070cf2a

	for _, pattern in ipairs(config.sourceMaps) do
	local sm = {}
	sm[1] = ('^%s$'):format(fs.source_native(fs.source_normalize(pattern[1])):gsub('[%^%$%(%)%%%.%[%]%+%-%?]', '%%%0'))
	if sm[1]:find '%*' then
	sm[1] = sm[1]:gsub('%*', '(.*)')
	end
	sm[2] = fs.path_normalize(pattern[2])
	sourceMaps[#sourceMaps + 1] = sm

throw an exception, since pattern[2] was nil.

Then, the code you mention was defaulting to LUAVERSION = 54 since the initialization function was not called and did not have the chance to update the value to 51 for luajit.

I repurposed the PR so the configuration is now checked. If the user forgets to add the mapping, it will throw a useful error in the logs:

if pattern[1] == nil or pattern[2] == nil then
    error(("Invalid source map entry. Check sourceMaps property in launch.json, entry #%d"):format(i - 1))
end

[actboy168]

Thank you. But it is still difficult for users to easily perceive errors when initializing the backend. A better approach is to check on the frontend.
6f98ba2

[jpeletier]

Ah, wonderful. I didn't know about that part of the code.
Problem solved! Thanks!