LuaLS / LuaLS/lua-language-server

Swap Params codeAction breaks code

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Lua
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Description

### How are you using the lua-language-server?

NeoVim

### Which OS are you using?

MacOS

### What is the issue affecting?

Formatting

### Expected Behaviour

Write lua code in neovim with codeActions triggered on buffer save. The lua code looks like the following:
```lua
vim.api.nvim_create_autocmd('BufWritePre', {})
```
and save, it will remain unchanged.

### Actual Behaviour

It changes the code to the following:
```lua
vim.api.nvim_create_autocmd({}, 'BufWritePre')
```

### Reproduction steps

1. Install lua-language-server
2. Setup lua lsp in neovim (can expand if needed)
3. Add the following autocmd to run codeactions on save
```lua
vim.api.nvim_create_autocmd('BufWritePre', {
group = vim.api.nvim_create_augroup('auto-format', { clear = false }),
buffer = ev.buf,
callback = function(evt)
local params = vim.lsp.util.make_range_params()
params.context = { }
local result = vim.lsp.buf_request_sync(evt.buf, "textDocument/codeAction", params)
for _, res in pairs(result or {}) do
for _, r in pairs(res.result or {}) do
if r.edit then
local enc = client.offset_encoding or "utf-16"
vim.lsp.util.apply_workspace_edit(r.edit, enc)
end
end
end

vim.lsp.buf.format({ bufnr = ev.buf, id = client.id, timeout_ms = 1000, async = false })
end,
})
```
4. Write some lua code and save that lua code with the cursor still on the same line.
5.

### Additional Notes

I was editing my neovim config and the lsp kept switching params like the following:
```lua
vim.api.nvim_create_autocmd('BufWritePre', {})
```
And after my PreWrite autocmd calls codeActions
```lua
vim.api.nvim_create_autocmd({}, 'BufWritePre')
```
which immediately breaks the code because the params are position sensitive.

It only does this if the cursor is on the line of the method call which I suppose makes sense since the code action is called with a range. My full autocmd works like this:
```lua
vim.api.nvim_create_autocmd('BufWritePre', {
group = vim.api.nvim_create_augroup('auto-format', { clear = false }),
buffer = ev.buf,
callback = function(evt)
local params = vim.lsp.util.make_range_params()
params.context = { }
local result = vim.lsp.buf_request_sync(evt.buf, "textDocument/codeAction", params)
for _, res in pairs(result or {}) do
for _, r in pairs(res.result or {}) do
if r.edit then
local enc = client.offset_encoding or "utf-16"
vim.lsp.util.apply_workspace_edit(r.edit, enc)
end
end
end

vim.lsp.buf.format({ bufnr = ev.buf, id = client.id, timeout_ms = 1000, async = false })
end,
})
```

I narrowed it down to this code action here https://github.com/LuaLS/lua-language-server/blob/b5e57c36a9a27b89eb283861fb8946fa787e37d8/script/core/code-action.lua#L462

Maybe I am holding it wrong and it is not supposed to be used in this way but I don't have a problem with other LSPs.

### Log File

No log entry was added during this behaviour.

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start by reproducing the issue in NeoVim with code actions triggered on save, using the positional-argument example from the report. Then inspect script/core/code-action.lua around line 462 and trace the Swap Params edit; done means the example remains unchanged after the code action runs.

Written by the indexing model from the issue text.

Assessment

Tech stack
lua, neovim
Domain
devtools, tooling
Issue type
Bug
Difficulty
3/5
Estimated time
1-2 days
Activity status
Quiet
Clarity
Clearly specified
Newbie friendliness
68/100

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