Bug: Empty textEdit.newText in the response of the textDocument/completion method

[darklam]

First of all many thanks for making this LSP happen; I've been waiting for this for years! ❤️

Now the issue is that the LSP returns a response for the textDocument/completion method with the newText always being an empty string and start/end being the same character. I think this breaks the completion in the Zed editor, so when trying to insert the completion nothing happens. In VS Code there might be different fallbacks for this case and it works.

Example response:

"textEdit": {
            "newText": "",
            "insert": {
                "start": {
                    "line": 75,
                    "character": 15
                },
                "end": {
                    "line": 75,
                    "character": 15
                }
            },
            "replace": {
                "start": {
                    "line": 75,
                    "character": 15
                },
                "end": {
                    "line": 75,
                    "character": 15
                }
            }
        }

This seems to happen on purpose in the LSAbstractCompletionProvider where textEdit is set to emptyTextEdit().

kotlin-lsp/features-impl/common/src/com/jetbrains/ls/api/features/impl/common/completion/LSAbstractCompletionProvider.kt

Line 76 in 17728b9

textEdit = emptyTextEdit(params.position),

Perhaps this is to implement the first mode described in the spec, but in this case the textEdit should be omitted completely if I understand it correctly.

This might be a misunderstanding on my part and not an issue, as I don't really know much about the LSP specification, but I saw that there was this issue in Zed and not in VS Code and wanted to dig around to figure out why.

[itsramiel]

This is also messes up auto completion in neovim

Screen.Recording.2025-10-23.at.3.06.17.PM.mov

[josuf107]

In case it helps anyone in nvim I patched the completion.lua script with

    local word = item.textEdit.newText
    local trimWhitespace = word:match('^(%S*)') or word     
    if trimWhitespace ~= '' then  
      return trimWhitespace       
    else                                                          
      return item.label                                       
    end 

Since newText is empty it returns the item.label which is the fallback in other cases. I'm not sure if this should be fixed in nvim or kotlin-lsp or both. It seems wrong to populate an empty newText, but there is a lot of fallback logic in completion.lua already.