Neovim LSP integration: Detach buffers only when attached

[larrybotha]

When switching to files that are not yet buffered I get the following error:

Buffer (id: [X]) is not attached to client (id: [Y]). Cannot detach.
"/path/to/file" 15L, 351B

This appears to be as a result of a race condition when detaching buffers - something in my config is potentially detaching buffers and then vectorcode attempts to do the same after they are already detached.

I tried to create a minimal neovim repro, but with the extent of my config it'd be a nightmare to minimise, so I've provided a screencast instead:

Recording.at.2025-12-16.22.53.40.Cropped.in.2025-12-16.22.54.37._compressed.webm

Reproduction Steps

• add a decade's worth of vim configs to neovim
• configure vectorcode lsp integration in neovim
• open an unbuffered file
• open a new unbuffered file in the same buffer

Expect: no error
Actual: error raised

Neovim Vectorcode Config

return {
	"Davidyz/VectorCode",
	version = "*",
	build = "uv tool upgrade vectorcode",
	dependencies = { "nvim-lua/plenary.nvim" },
	cond = function()
		return vim.fn.executable("vectorcode") == 1
	end,
	event = { "BufReadPost", "BufNewFile" },
	config = function()
		require("vectorcode").setup(
			---@type VectorCode.Opts
			{
				cli_cmds = {
					vectorcode = "vectorcode",
				},
				-- options used when attaching to LSP, below
				---@type VectorCode.RegisterOpts
				async_opts = {
					debounce = 100, -- Debounce time in milliseconds to avoid excessive updates
					events = { "BufWritePost", "InsertLeave", "BufReadPost" }, -- Events that trigger automatic file indexing
					exclude_this = true, -- Exclude current buffer from automatic indexing
					n_query = 1, -- Number of queries to send for each indexing operation
					notify = true, -- Show notifications when indexing operations occur
					query_cb = require("vectorcode.utils").make_surrounding_lines_cb(-1), -- Use surrounding lines as context for better indexing
					-- Don't automatically index when files are manually registered
					-- Use `:VectorCode register` to register specific files for indexing
					run_on_register = false,
				},
				async_backend = "lsp", -- Backend to use for async operations (default or lsp)
				exclude_this = true, -- Exclude current buffer from operations
				n_query = 10, -- Number of queries to send for each operation
				notify = true, -- Show notifications for operations
				timeout_ms = 5000, -- Timeout in milliseconds for operations
				on_setup = {
					update = true, -- Update VectorCode on setup
					lsp = false, -- Disable automatic LSP startup during setup
				},
				sync_log_env_var = false, -- Don't sync environment variables for logging
			}
		)

		vim.api.nvim_create_autocmd("LspAttach", {
			callback = function()
				local cacher = require("vectorcode.cacher")
				local bufnr = vim.api.nvim_get_current_buf()

				cacher.utils.async_check("config", function()
					cacher.lsp.register_buffer(bufnr, {
						-- provide rich context for LSP queries
						n_query = 10,
					})
				end, nil)
			end,
			desc = "Register buffer for VectorCode",
		})
	end,
}

Solution

Before calling vim.lsp.buf_detach_client, check that the buffer is attached using vim.lsp.buf_is_attached

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 99.72%. Comparing base (56f21eb) to head (7e20d6a).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #303   +/-   ##
=======================================
  Coverage   99.72%   99.72%           
=======================================
  Files          25       25           
  Lines        1845     1845           
=======================================
  Hits         1840     1840           
  Misses          5        5           

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[Davidyz]

Thanks for the contribution, and sorry for taking so long to process this. I was sick and couldn't take care of my Github.

[larrybotha]

no worries - thanks for the hard work, much appreciated!