[mini.completion] Confusion between completefunc and omnifunc

[pkazmier]

Embarrassingly, I've spent the last 3 hours trying to figure out why completion behaves differently when the source_func is "completefunc" vs "omnifunc". For example, if my buffer contains:

local H ={}
H.test1 = function() end
H.test2 = function() end
H.test3 = function() end

When source_func = "completefunc":

1. Go, end of file, open line
2. H, popup opens with "H variable" (expected)
3. ., popup opens with "test1() Function", "test2() Function", and "test3() Function" (expected)

When source_func = "omnifunc":

1. Go, end of file, open line
2. H, popup opens with "H variable" (expected)
3. ., popup dismissed (not expected)

I've added print statements all over mini.completion and it appears that the event CompleteDonePre is fired when I press . with "completefunc", but it is not fired with "omnifunc". When CompleteDonePre is fired, it results in H.stop_completion being passed nil, which resets the source.

And to continue the "omnifunc" above:

4. t, popup opens showing "test1", "test2", "test3". These come from the fallback, not LSP, because the source was not reset.

I suppose my expectation of how it should work is probably due to some fundamental misunderstanding about vim's completion function vs omni function. I tried reading help pages, but have not found the answer. It's not for the lack of trying. Can you help elaborate for me?

I prefer the behavior when the source in "completefunc", but I only swapped it because of the note in mini.completion about the better way of hooking this up is to do so in the LSP on_attach function. I wish I never read that paragraph now as I could have saved my entire morning 😄

[pkazmier]

Here is a minimal configuration one can test with:

-- Clone 'mini.nvim' manually in a way that it gets managed by 'mini.deps'
local path_package = vim.fn.stdpath("data") .. "/site/"
local mini_path = path_package .. "pack/deps/start/mini.nvim"
if not vim.loop.fs_stat(mini_path) then
  vim.cmd('echo "Installing `mini.nvim`" | redraw')
  local clone_cmd = {
    "git",
    "clone",
    "--filter=blob:none",
    "https://github.com/echasnovski/mini.nvim",
    mini_path,
  }
  vim.fn.system(clone_cmd)
  vim.cmd("packadd mini.nvim | helptags ALL")
  vim.cmd('echo "Installed `mini.nvim`" | redraw')
end

-- Set up 'mini.deps' (customize to your liking)
require("mini.deps").setup({ path = { package = path_package } })
MiniDeps.add("williamboman/mason.nvim")
MiniDeps.add("williamboman/mason-lspconfig.nvim")
MiniDeps.add("neovim/nvim-lspconfig")

require("mini.completion").setup({
  lsp_completion = {
    source_func = "omnifunc",
    auto_setup = true,
  },
})
require("mason").setup()
require("mason-lspconfig").setup({
        ensure_installed = { "lua_ls" }
})
require("lspconfig").lua_ls.setup({
  on_attach = function(client, bufnr)
    -- vim.bo[bufnr].omnifunc = "v:lua.MiniCompletion.completefunc_lsp"
  end,
})

[echasnovski]

Thanks for the detailed description with explicit steps and setup!

Embarrassingly, I've spent the last 3 hours trying to figure out why completion behaves differently when the source_func is "completefunc" vs "omnifunc".

I can reproduce even with by slightly tweaking my own setup. Plan to take a look closer in the near future.

I suppose my expectation of how it should work is probably due to some fundamental misunderstanding about vim's completion function vs omni function. I tried reading help pages, but have not found the answer. It's not for the lack of trying. Can you help elaborate for me?

It is surely can be an issue in 'mini.completion'. That said, I also am not aware of the obvious difference between how 'completefunc' and 'omnifunc' operates.

[echasnovski]

This should be solved on latest main.