Improving on the biome fixAll + organizeImports on-save solution for Neovim — fixing remaining race conditions.

[ridwanyinus]

I came across discussion #7931 by @HendrikPetertje which pointed me in the right direction, but I ran into a few issues with the approach that I had to dig into further. Sharing my fixes here in case others hit the same wall.

What still didn't work from the original post

Even after switching to buf_request_sync, I was still seeing:

• The unsaved indicator (green dot) reappearing after save
• Fixes applying inconsistently across different files
• A position_encoding warning spam in the console when multiple LSPs were attached

The problem

Using vim.lsp.buf.code_action { apply = true } inside BufWritePre looks synchronous but isn't. The file write completes before the code actions finish, causing:

• Inconsistent fixes (works sometimes, not others)
• The unsaved indicator reappearing after save because edits land after the write
• Files occasionally getting rewritten on the next save

The solution

Use vim.lsp.buf_request_sync which actually blocks until the LSP responds, then apply edits manually before the write happens:

local function apply_code_action_sync(bufnr, client, action_kind)
  local params = vim.lsp.util.make_range_params(0, client.offset_encoding)
  params.context = { only = { action_kind }, diagnostics = {} }

  local results = vim.lsp.buf_request_sync(
    bufnr,
    "textDocument/codeAction",
    params,
    3000
  )

  if not results then return end

  for _, res in pairs(results) do
    for _, action in pairs(res.result or {}) do
      if action.edit then
        vim.lsp.util.apply_workspace_edit(action.edit, client.offset_encoding)
      elseif action.command then
        client:exec_cmd(action.command)
      end
    end
  end
end

vim.api.nvim_create_autocmd("LspAttach", {
  callback = function(args)
    local bufnr = args.buf
    local client = vim.lsp.get_client_by_id(args.data.client_id)

    if client and client.name == "biome" then
      vim.api.nvim_create_autocmd("BufWritePre", {
        buffer = bufnr,
        callback = function()
          apply_code_action_sync(bufnr, client, "source.organizeImports")
          apply_code_action_sync(bufnr, client, "source.fixAll")
        end,
      })
    end
  end,
})

A few things worth noting

• Pass client.offset_encoding explicitly to both make_range_params and apply_workspace_edit to avoid the position_encoding warning when multiple LSPs (e.g. ts_ls) are attached to the same buffer
• client:exec_cmd() is the Neovim 0.10+ idiomatic way — vim.lsp.buf.execute_command is deprecated
• Disable formatting on ts_ls so Biome owns it: set client.server_capabilities.documentFormattingProvider = false in your ts_ls on_init

Hope this helps someone who already tried #7931 and is still stuck!