completion returns wrong and according to the spec invalid results

[max397574]

How are you using the lua-language-server?

NeoVim

Which OS are you using?

MacOS

What is the issue affecting?

Completion

Expected Behaviour

Get back a completion item which does nothing which is explicitly forbidden in the spec and actually is correct

Actual Behaviour

Returns a completion item with a textEdit which makes no sense and additionalTextEdits which wouldn't even be allowed by the spec

Reproduction steps

I completed with the following context (notice that the cursor position uses different based indexing because neovim being like it is)

local entry_context = {
    bufnr = 1,
    cursor = { col = 35, row = 1 },
    line = "    completion_item.textEdit.range.",
    line_before_cursor = "    completion_item.textEdit.range.",
    previous = nil,
    reason = 1,
}

I get back an entry like this

local completion_item = {
    additionalTextEdits = {
        {
            newText = "",
            range = {
                ["end"] = { character = 35, line = 69 },
                start = { character = 34, line = 69 },
            },
        },
    },
    data = { id = 119, uri = "not relevant" },
    detail = "lsp.Position",
    documentation = { kind = "markdown", value = "not relevant" },
    insertTextFormat = 2,
    kind = 5,
    label = '"end"',
    sortText = "0001",
    textEdit = {
        newText = '["end"]',
        range = {
            ["end"] = { character = 35, line = 69 },
            start = { character = 4, line = 71 },
        },
    },
}

Additional Notes

I have no idea why the text edit would modify 3 different lines when just a single statement would have to be inserted.
About additionalTextEdits from the lsp specification:

/**
* An optional array of additional text edits that are applied when
* selecting this completion. Edits must not overlap (including the same
* insert position) with the main edit nor with themselves.
*
* Additional text edits should be used to change text unrelated to the
* current cursor position (for example adding an import statement at the
* top of the file if the completion item will insert an unqualified type).
*/

In this case the additionalTextEdit overlaps with the edit and also doesn't what's it intended for (2nd paragraph)

Log File

No response

[max397574]

@sumneko @CppCXY @tomlau10 could you help me with this or point me in the direction where I could fix this in the code myself?

[max397574]

still happening with latests version
is there anything I can do about this?

[tomlau10]

I use vscode and I don't quite understand what this issue is talking about.

I also cannot follow your Reproduction steps 😅

• What do you mean by context when giving the local entry_context example?
  Is it the file content?
• What errors are you seeing?
  Or do you mean you are having incorrect completion result list when triggering auto completion?
• Can you provide some code snippets where triggering auto completion will return incorrect result list?
  Similar to the descriptions in this issue: vscode does not list server-provided completion items. #2783
  • the code snippet
  • the cursor position when trigger auto completion
  • the expected and actual result after triggering auto completion
• Can you reproduce this on vscode?
  If yes then this issue is related to LuaLS (the language server itself), otherwise this maybe neovim specific 🤔

---

I'd be happy to help if you can elaborate more on this issue, though I can't guarantee I'll be able to find a solution 😄 @max397574

[max397574]

I'm writing a completion engine for neovim and there I get completions when I have a type with an end field (which is the case for lsp ranges)

the entry context is the context in which completion was requested/received from the server
I0m not seeing any errors. I just get a completion item which does really wrong things.

I'll try to create a minimal example

I could try this on vscode
But perhaps it won't be reproducible because e..g some other completion engine I used in neovim didn't even return the entry because it was filtered out as a duplicate of simply .end

[tomlau10]

I have a type with an end field

I just crafted a range type with the field start and end, and I experienced some strange issue when auto completing the end field. 😕
As you may know end is a lua keyword and we just can't write t.end, we have to write it as t["end"].

---@class range
---@field start integer
---@field end integer

---@type range
local r

r["|"] --< `|` is the cursor and I trigger completion there

• the completion list does includes start and end ✅
  • but when I select start, the applied result is incorrect => r["tar"] ❌
  • also when I select end, the applied result is wrong 🙄 => r["n"] ❌
• it seems to me that when completing literal inside "", the range index doesn't adjust for the surrounding double quotes ""
  => causing the applied results have the first and last character stripped.

---

However this is different from what you're encountering. And there maybe more bugs in LuaLS side of it's completion function. 😂

[max397574]

minimal example

---@class Range
---@field start integer
---@field end integer

---@type Range
local x = { ["end"] = 3, start = 5 }
x.|
local y = 3

cursor is the |
select the completion "end" (notice the quotes)
it seems relevant that there is code after the line on which you complete

this leads to the invalid completion item as noted above (overlapping, multiple lines)

[tomlau10]

I just tried with you example:

• in vscode, only end and start is provided when i trigger completion
  
• and you're right that "it seems relevant that there is code after the line on which you complete"
  because after I remove the local y = 3 and trigger completion again, another "end" is on the list
  

Maybe in the 1st case, there's the wrong completion item and vscode will filter it out silently.

---

With some digging in the code base, I believe the logic of handling completion request is here:

• the callback when receiving a textDocument/completion request
  

  lua-language-server/script/provider/provider.lua

  Lines 609 to 636 in aaf1624

  	m.register 'textDocument/completion' {
  	---@async
  	function (params)
  	local uri = files.getRealUri(params.textDocument.uri)
  	if not workspace.isReady(uri) then
  	return nil
  	end
  	local _ <close> = progress.create(uri, lang.script.WINDOW_PROCESSING_COMPLETION, 0.5)
  	--log.info(util.dump(params))
  	local core = require 'core.completion'
  	--log.debug('textDocument/completion')
  	--log.debug('completion:', params.context and params.context.triggerKind, params.context and params.context.triggerCharacter)
  	local state = files.getState(uri)
  	if not state then
  	return
  	end
  	local triggerCharacter = params.context and params.context.triggerCharacter
  	if config.get(uri, 'editor.acceptSuggestionOnEnter') ~= 'off' then
  	if triggerCharacter == '\n'
  	or triggerCharacter == '{'
  	or triggerCharacter == ',' then
  	return
  	end
  	end
  	--await.setPriority(1000)
  	local clock = os.clock()
  	local pos = converter.unpackPosition(state, params.position)
  	local result = core.completion(uri, pos, triggerCharacter)

• then it triggers core.completion which returns a result[]
  

  lua-language-server/script/core/completion/completion.lua

  Lines 2388 to 2398 in aaf1624

  	local function completion(uri, position, triggerCharacter)
  	local state = files.getLastState(uri) or files.getState(uri)
  	if not state then
  	return nil
  	end
  	clearStack()
  	diagnostic.pause()
  	local _ <close> = diagnostic.resume
  	local results = {}
  	tracy.ZoneBeginN 'completion #2'
  	tryCompletions(state, position, triggerCharacter, results)

• it triggers the tryCompletions() there and each step will push result into the results[]

That's all I know, maybe you can start debugging from there 🤔

[max397574]

well but the language server does also return items in the case with the local y
which are just filtered out by vscode then it seems. And it looks like they are only problematic in this case. Otherwise I also get the completion and it also is correct.

[max397574]

I'll try to look into the code parts you sent

[tomlau10]

I forgot to mention that, you can start LuaLS with --rpcjson=true argument, and LuaLS will logs the json data that received and sent in the log file.

the language server does also return items in the case with the local y

And yes I confirmed in the case with the local y, LuaLS also return the wrong completion item, as seen from the log. Below is the beautified json data:

{
  "id": 20,
  "jsonrpc": "2.0",
  "result": {
    "isIncomplete": false,
    "items": [
      {
        "additionalTextEdits": [
          {
            "newText": "",
            "range": {
              "end": {
                "character": 2,
                "line": 6
              },
              "start": {
                "character": 1,
                "line": 6
              }
            }
          }
        ],
        "data": {
          "id": 1,
          "uri": "file:///c%3A/Users/TomLau/test/test.lua"
        },
        "insertTextFormat": 2,
        "kind": 13,
        "label": "\"end\"",
        "sortText": "0001",
        "textEdit": {
          "newText": "[\"end\"]",
          "range": {
            "end": {
              "character": 2,
              "line": 6
            },
            "start": {
              "character": 0,
              "line": 8
            }
          }
        }
      },
      {
        "data": {
          "id": 2,
          "uri": "file:///c%3A/Users/TomLau/test/test.lua"
        },
        "insertTextFormat": 2,
        "kind": 5,
        "label": "end",
        "sortText": "0002"
      },
      {
        "data": {
          "id": 3,
          "uri": "file:///c%3A/Users/TomLau/test/test.lua"
        },
        "insertTextFormat": 2,
        "kind": 13,
        "label": "start",
        "sortText": "0003"
      }
    ]
  }
}

[tomlau10]

For the case when a completion item's newText is a ["field"], I believe it is handled by checkFieldFromFieldToIndex()

lua-language-server/script/core/completion/completion.lua

Lines 449 to 477 in aaf1624

	local function checkFieldFromFieldToIndex(state, name, src, parent, word, startPos, position)
	if name:match(guide.namePatternFull) then
	if not name:match '[\x80-\xff]'
	or config.get(state.uri, 'Lua.runtime.unicodeName') then
	return nil
	end
	name = ('%q'):format(name)
	end
	local textEdit, additionalTextEdits
	local startOffset = guide.positionToOffset(state, startPos)
	local offset = guide.positionToOffset(state, position)
	local wordStartOffset
	if word == '' then
	wordStartOffset = state.lua:match('()%S', startOffset + 1)
	if wordStartOffset then
	wordStartOffset = wordStartOffset - 1
	else
	wordStartOffset = offset
	end
	else
	wordStartOffset = offset - #word
	end
	local wordStartPos = guide.offsetToPosition(state, wordStartOffset)
	local newText = ('[%s]'):format(name)
	textEdit = {
	start = wordStartPos,
	finish = position,
	newText = newText,
	}

Maybe the offset calculation here is incorrect 🤔

[tomlau10]

(Off topic)

Oh for the incorrect completion inside quoted string that I mentioned in this comment: #2762 (comment), I found that you have reported it in another issue: #2688.

Maybe during your debugging journey, you can fix both of them 😄

[max397574]

@sumneko I tried to debug this myself but couldn't figure it out. Could you take a look at this?

[tomlau10]

I don't think author have time to debug this, given that seems no others are encountering this issue, so this have a very low low priority ☹️ .

As many editors will just ignore invalid entries on client side, maybe in the meantime you can filter invalid result in your client side as well? Another approach that I can think of is to filter invalid result on LuaLS side before it returns the result items, but this just hides the problem ... 😇

So seems the best way is you tackle it in your client side, and leave this issue open in LuaLS repo. Maybe in someday it will get solved finally, by author or by others, (or maybe not...) 😂 @max397574