Last typed word remain as completion matcher even after deleting it

[azufr]

Warning: I will close the issue without the minimal init.vim and the reproduction instructions.

Problems summary

Last typed character or word? remain as completion matcher even after deleting it using backspace. As a result, only completion candidates that matched with last typed word are returned

Expected

After deleting word or character, completion matcher should be reset to empty string and all completion candidates should be return

Environment Information

• ddc.vim version (SHA1): 4da0d40efff84f3e5bc86947bc2448481fbbda7d

• ddc-source-nvim-lsp version (SHA1): 922e38f75c8e588321e78717557fc1d2b5013983

• denops.vim version (SHA1): 6b29032365f82fc1ef78d206e4019fd510ea51fb

• deno version(deno -V output):

  deno 1.33.0

• OS: Arch Linux

• neovim/Vim :version output:

  
  NVIM v0.9.0
  Build type: Release
  LuaJIT 2.1.0-beta3
  
  system vimrc file: "$VIM/sysinit.vim"
  fall-back for $VIM: "/usr/share/nvim"

Run :checkhealth for more info

## Provide a minimal init.vim/vimrc without plugin managers (Required!)

```lua
vim.opt.runtimepath:append({ '~/.local/share/nvim/lazy/denops.vim' })
vim.opt.runtimepath:append({ '~/.local/share/nvim/lazy/ddc.vim' })
vim.opt.runtimepath:append({ '~/.local/share/nvim/lazy/ddc-around' })
vim.opt.runtimepath:append({ '~/.local/share/nvim/lazy/ddc-fuzzy' })
vim.opt.runtimepath:append({ '~/.local/share/nvim/lazy/ddc-ui-pum' })
vim.opt.runtimepath:append({ '~/.local/share/nvim/lazy/pum.vim' })
vim.opt.runtimepath:append({ '~/.local/share/nvim/lazy/ddc-source-nvim-lsp' })
vim.opt.runtimepath:append({ '~/.local/share/nvim/lazy/nvim-lspconfig' })

vim.opt.completeopt = { 'menu', 'menuone', 'noinsert' }
vim.fn['pum#set_option']('use_complete', false)
vim.fn['pum#set_option']('scrollbar_char', '')
local ddc_opts = {
    ui = 'pum',
    autoCompleteEvents = { 'InsertEnter', 'TextChangedI', 'TextChangedP', 'CmdlineChanged', 'CmdlineEnter' },
    sources = { 'nvim-lsp', 'around' },
    sourceOptions = {
        _ = {
            matchers = { 'matcher_fuzzy' },
            sorters = { 'sorter_fuzzy' }
        },
        ['nvim-lsp'] = {
            mark = '[lsp]',
            dup = 'keep',
            forceCompletionPattern = [[\.\w*|:\w*|->\w*]],
            minAutoCompleteLength = 2,
            maxItems = 1000,
            ignoreCase = true,
        },
        ['around'] = {
            mark = '[A]'
        }
    }
}

vim.fn['ddc#custom#patch_global'](ddc_opts)
vim.fn['ddc#enable']()

vim.keymap.set('i', '<C-y>', '<cmd>call pum#map#confirm()<cr>')
vim.keymap.set('i', '<C-e>', '<cmd>call pum#map#cancel()<cr>')
vim.keymap.set('i', '<C-n>', '<cmd>call pum#map#insert_relative(+1)<cr>')
vim.keymap.set('i', '<C-p>', '<cmd>call pum#map#insert_relative(-1)<cr>')

-- Setup language servers.
local lspconfig = require('lspconfig')
lspconfig.pyright.setup({
    cmd = { '/opt/language-servers/bin/pyright-langserver', '--stdio' }
})

-- Global mappings.
-- See `:help vim.diagnostic.*` for documentation on any of the below functions
vim.keymap.set('n', '<space>e', vim.diagnostic.open_float)
vim.keymap.set('n', '[d', vim.diagnostic.goto_prev)
vim.keymap.set('n', ']d', vim.diagnostic.goto_next)
vim.keymap.set('n', '<space>q', vim.diagnostic.setloclist)

-- Use LspAttach autocommand to only map the following keys
-- after the language server attaches to the current buffer
vim.api.nvim_create_autocmd('LspAttach', {
    group = vim.api.nvim_create_augroup('UserLspConfig', {}),
    callback = function(ev)
        -- Enable completion triggered by <c-x><c-o>
        vim.bo[ev.buf].omnifunc = 'v:lua.vim.lsp.omnifunc'

        -- Buffer local mappings.
        -- See `:help vim.lsp.*` for documentation on any of the below functions
        local opts = { buffer = ev.buf }
        vim.keymap.set('n', 'gD', vim.lsp.buf.declaration, opts)
        vim.keymap.set('n', 'gd', vim.lsp.buf.definition, opts)
        vim.keymap.set('n', 'K', vim.lsp.buf.hover, opts)
        vim.keymap.set('n', 'gi', vim.lsp.buf.implementation, opts)
        vim.keymap.set('n', '<C-k>', vim.lsp.buf.signature_help, opts)
        vim.keymap.set('n', '<space>wa', vim.lsp.buf.add_workspace_folder, opts)
        vim.keymap.set('n', '<space>wr', vim.lsp.buf.remove_workspace_folder, opts)
        vim.keymap.set('n', '<space>wl', function()
            print(vim.inspect(vim.lsp.buf.list_workspace_folders()))
        end, opts)
        vim.keymap.set('n', '<space>D', vim.lsp.buf.type_definition, opts)
        vim.keymap.set('n', '<space>rn', vim.lsp.buf.rename, opts)
        vim.keymap.set({ 'n', 'v' }, '<space>ca', vim.lsp.buf.code_action, opts)
        vim.keymap.set('n', 'gr', vim.lsp.buf.references, opts)
        vim.keymap.set('n', '<space>f', function()
            vim.lsp.buf.format { async = true }
        end, opts)
    end,
})

How to reproduce the problem from neovim/Vim startup (Required!)

following steps are for python/pyright languange server. this problem also happened with lua/lua-ls.

1. open .py file
2. type the following

   import os
   os.path

3. delete .path part
4. type . and only candidate match with path are returned.
5. It should be reset and return all completion candidates from os module

Screenshot (if possible)

Upload the log messages by :redir and :message (if errored)

No Error

[Shougo]

You need to set backspaceCompletion option.

                *ddc-option-backspaceCompletion*
backspaceCompletion
        If it is enabled, ddc.vim will complete even when backspace is
        typed.
        Note: It is disabled by default since backspace completion
        will cause completion flicker.

        Default: v:false

[azufr]

It was fixed by this. Thanks.