script\vm\compiler.lua:2023: attempt to index a nil value

[citRaTTV]

How are you using the lua-language-server?

Visual Studio Code Extension (sumneko.lua)

Which OS are you using?

Windows

What is the issue affecting?

Other

Expected Behaviour

No error

Actual Behaviour

Errors are thrown during Diagnose Workspace & while editing files.

Reproduction steps

1. Open LUA project in VSCode
2. Wait for workspace diagnostic run
3. Error pops up during run

Additional Notes

No response

Log File

[17:09:19.163][info] [#0:script\provider\diagnostic.lua:560]: Diagnostics scope [file:///z%3A/projects/fivem-dev], files count:[3121]
[17:09:19.407][error][#0:script\vm\compiler.lua:2023]: script\vm\compiler.lua:2023: attempt to index a nil value
stack traceback:
	script\vm\compiler.lua:2023: in upvalue 'compileByParentNode'
	script\vm\compiler.lua:2052: in function 'vm.vm.compileNode'
	script\vm\function.lua:233: in function 'vm.vm.countReturnsOfSource'
	script\core\diagnostics\missing-return.lua:57: in local 'callback'
	script\parser\guide.lua:756: in function 'parser.guide.eachSourceType'
	script\core\diagnostics\missing-return.lua:51: in function 'core.diagnostics.missing-return'
	script\core\diagnostics\init.lua:119: in upvalue 'check'
	script\core\diagnostics\init.lua:181: in function 'core.diagnostics'
	[C]: in function 'xpcall'
	script\provider\diagnostic.lua:337: in function 'provider.diagnostic.doDiagnostic'
	[C]: in function 'xpcall'
	script\provider\diagnostic.lua:598: in local 'callback'
	script\provider\diagnostic.lua:569: in function 'provider.diagnostic.awaitDiagnosticsScope'
	script\provider\diagnostic.lua:597: in function <script\provider\diagnostic.lua:595>
[17:09:19.412][error][#0:script\vm\compiler.lua:2023]: script\vm\compiler.lua:2023: attempt to index a nil value
stack traceback:
	script\vm\compiler.lua:2023: in upvalue 'compileByParentNode'
	script\vm\compiler.lua:2052: in function 'vm.vm.compileNode'
	script\vm\function.lua:233: in function 'vm.vm.countReturnsOfSource'
	script\core\diagnostics\missing-return.lua:57: in local 'callback'
	script\parser\guide.lua:756: in function 'parser.guide.eachSourceType'
	script\core\diagnostics\missing-return.lua:51: in function 'core.diagnostics.missing-return'
	script\core\diagnostics\init.lua:119: in upvalue 'check'
	script\core\diagnostics\init.lua:181: in function 'core.diagnostics'
	[C]: in function 'xpcall'
	script\provider\diagnostic.lua:337: in function 'provider.diagnostic.doDiagnostic'
	[C]: in function 'xpcall'
	script\provider\diagnostic.lua:598: in local 'callback'
	script\provider\diagnostic.lua:569: in function 'provider.diagnostic.awaitDiagnosticsScope'
	script\provider\diagnostic.lua:597: in function <script\provider\diagnostic.lua:595>
[17:09:19.421][error][#0:script\vm\compiler.lua:2023]: script\vm\compiler.lua:2023: attempt to index a nil value
stack traceback:
	script\vm\compiler.lua:2023: in upvalue 'compileByParentNode'
	script\vm\compiler.lua:2052: in function 'vm.vm.compileNode'
	script\vm\function.lua:233: in function 'vm.vm.countReturnsOfSource'
	script\core\diagnostics\missing-return.lua:57: in local 'callback'
	script\parser\guide.lua:756: in function 'parser.guide.eachSourceType'
	script\core\diagnostics\missing-return.lua:51: in function 'core.diagnostics.missing-return'
	script\core\diagnostics\init.lua:119: in upvalue 'check'
	script\core\diagnostics\init.lua:181: in function 'core.diagnostics'
	[C]: in function 'xpcall'
	script\provider\diagnostic.lua:337: in function 'provider.diagnostic.doDiagnostic'
	[C]: in function 'xpcall'
	script\provider\diagnostic.lua:598: in local 'callback'
	script\provider\diagnostic.lua:569: in function 'provider.diagnostic.awaitDiagnosticsScope'
	script\provider\diagnostic.lua:597: in function <script\provider\diagnostic.lua:595>
[17:09:19.520][error][#0:script\vm\compiler.lua:2023]: script\vm\compiler.lua:2023: attempt to index a nil value
stack traceback:
	script\vm\compiler.lua:2023: in upvalue 'compileByParentNode'
	script\vm\compiler.lua:2052: in function 'vm.vm.compileNode'
	script\vm\function.lua:233: in function 'vm.vm.countReturnsOfSource'
	script\core\diagnostics\missing-return.lua:57: in local 'callback'
	script\parser\guide.lua:756: in function 'parser.guide.eachSourceType'
	script\core\diagnostics\missing-return.lua:51: in function 'core.diagnostics.missing-return'
	script\core\diagnostics\init.lua:119: in upvalue 'check'
	script\core\diagnostics\init.lua:181: in function 'core.diagnostics'
	[C]: in function 'xpcall'
	script\provider\diagnostic.lua:337: in function 'provider.diagnostic.doDiagnostic'
	[C]: in function 'xpcall'
	script\provider\diagnostic.lua:598: in local 'callback'
	script\provider\diagnostic.lua:569: in function 'provider.diagnostic.awaitDiagnosticsScope'
	script\provider\diagnostic.lua:597: in function <script\provider\diagnostic.lua:595>
[17:09:19.630][error][#0:script\vm\compiler.lua:2023]: script\vm\compiler.lua:2023: attempt to index a nil value
stack traceback:
	script\vm\compiler.lua:2023: in upvalue 'compileByParentNode'
	script\vm\compiler.lua:2052: in function 'vm.vm.compileNode'
	script\vm\function.lua:233: in function 'vm.vm.countReturnsOfSource'
	script\core\diagnostics\missing-return.lua:57: in local 'callback'
	script\parser\guide.lua:756: in function 'parser.guide.eachSourceType'
	script\core\diagnostics\missing-return.lua:51: in function 'core.diagnostics.missing-return'
	script\core\diagnostics\init.lua:119: in upvalue 'check'
	script\core\diagnostics\init.lua:181: in function 'core.diagnostics'
	[C]: in function 'xpcall'
	script\provider\diagnostic.lua:337: in function 'provider.diagnostic.doDiagnostic'
	[C]: in function 'xpcall'
	script\provider\diagnostic.lua:598: in local 'callback'
	script\provider\diagnostic.lua:569: in function 'provider.diagnostic.awaitDiagnosticsScope'
	script\provider\diagnostic.lua:597: in function <script\provider\diagnostic.lua:595>
[17:09:19.745][error][#0:script\vm\compiler.lua:2023]: script\vm\compiler.lua:2023: attempt to index a nil value
stack traceback:
	script\vm\compiler.lua:2023: in upvalue 'compileByParentNode'
	script\vm\compiler.lua:2052: in function 'vm.vm.compileNode'
	script\vm\function.lua:233: in function 'vm.vm.countReturnsOfSource'
	script\core\diagnostics\missing-return.lua:57: in local 'callback'
	script\parser\guide.lua:756: in function 'parser.guide.eachSourceType'
	script\core\diagnostics\missing-return.lua:51: in function 'core.diagnostics.missing-return'
	script\core\diagnostics\init.lua:119: in upvalue 'check'
	script\core\diagnostics\init.lua:181: in function 'core.diagnostics'
	[C]: in function 'xpcall'
	script\provider\diagnostic.lua:337: in function 'provider.diagnostic.doDiagnostic'
	[C]: in function 'xpcall'
	script\provider\diagnostic.lua:598: in local 'callback'
	script\provider\diagnostic.lua:569: in function 'provider.diagnostic.awaitDiagnosticsScope'
	script\provider\diagnostic.lua:597: in function <script\provider\diagnostic.lua:595>

[tomlau10]

script\vm\compiler.lua:2023 is trying to index the node cache of source object

lua-language-server/script/vm/compiler.lua

Lines 2022 to 2023 in bd0af02

	local function compileByParentNode(source)
	if vm.getNode(source):isTyped() then

attempt to index a nil value

This means that the node cache is not found, which it should exist during the whole process of vm.compileNode
I suspect that at sometime, vm.removeNode is called on this source object 🤔

---

From the diff between 3.9.3 => 3.10.0, two vm.removeNode function call is added:

• script/vm/compiler.lua:581
I added this in fix: inconsistent type narrow due to outdated node caches of call.args #2765 to fix Function overloads with function args not narrowing inner function params #2758
• script/core/diagnostics/missing-fields.lua:18
  added in improve the missing-fields logic to be able to correctly handle classes defined several times #2770 to fix inconsistent behavior for diagnosis (missing-fields). #2769

As the latter one is just calling vm.removeNode inside a foreach of a diagnostics test, I don't think that one is related. This lefts the former one which trying to do vm.removeNode in a matchCall().

---

Can your workspace reproduce this issue 100%? @citRaTTV
As I don't have a workspace to reproduce this, seems we need your help to debug on your side .
The debugging approach that I can think of:

• Make sure your can reproduce this 100%, or at least very frequently
• Then revert the change in fix: inconsistent type narrow due to outdated node caches of call.args #2765, it is just a forloop here:
  

  lua-language-server/script/vm/compiler.lua

  Lines 578 to 583 in bd0af02

  	if call.args then
  	-- clear node caches of args to allow recomputation with the type narrowed call
  	for _, arg in ipairs(call.args) do
  	vm.removeNode(arg)
  	end
  	end

  
  You can do this by modifying the extension script file directly, it should be located in a path like C:\Users\TomLau\.vscode\extensions\sumneko.lua-3.10.0-win32-x64\server\script
• After modifying, restart vscode to see if this issue persist
• Until then we can know if this line of change is the culprit, and think about the resolution 🙏

PS:
If it is confirmed that #2765 is the culprit, of course we can request extension author to revert that immediately.
But then as we don't have a reproducible workspace yet, we can never fix #2758 properly without causing error on your side.
So we need your help 🙏

[tomlau10]

glad that it is fixed so quickly 👍

[citRaTTV]

I didn't even get a chance to help out 😂. Let me know if you need anything else from me, thanks for addressing this so quickly!