The nvim-dap REPL can be customized to use custom commands using the following syntax:

local repl = require('dap.repl')
repl.commands = vim.tbl_extend('force', repl.commands, {
  custom_commands = {
    ['.restart'] = function()
      dap.restart()
      repl.open()
      vim.cmd.wincmd('j')
    end,
    ['.clear'] = repl.clear()
  },
})

When using these custom commands alongside cmp-dap, an error is thrown:

Error detected while processing TextChangedI Autocommands for "*":
Error executing lua callback: vim/shared.lua:0: s: expected string, got function
stack traceback:
        [C]: in function 'error'
        vim/shared.lua: in function 'validate'
        vim/shared.lua: in function 'startswith'
        ...chan/.local/share/nvim/lazy/cmp-dap/lua/cmp_dap/init.lua:88: in function 'complete'
        .../chan/.local/share/nvim/lazy/nvim-cmp/lua/cmp/source.lua:334: in function 'complete'
        /home/chan/.local/share/nvim/lazy/nvim-cmp/lua/cmp/core.lua:299: in function 'complete'
        /home/chan/.local/share/nvim/lazy/nvim-cmp/lua/cmp/core.lua:169: in function 'callback'
        /home/chan/.local/share/nvim/lazy/nvim-cmp/lua/cmp/core.lua:229: in function 'autoindent'
        /home/chan/.local/share/nvim/lazy/nvim-cmp/lua/cmp/core.lua:161: in function 'on_change'
        /home/chan/.local/share/nvim/lazy/nvim-cmp/lua/cmp/init.lua:338: in function 'callback'
        ...local/share/nvim/lazy/nvim-cmp/lua/cmp/utils/autocmd.lua:49: in function 'emit'
        ...local/share/nvim/lazy/nvim-cmp/lua/cmp/utils/autocmd.lua:23: in function <...local/share/nvim/lazy/nvim-cmp/lua/cmp/utils/autocmd.lua:22>

Silly question, but I can't seem to use it with Neovim 0.8.0.
My cmp config is quiet vast so I removed everything and just left the stuff from the README.
It still doesn't work and CmpStatus lists cmp-dap under unavailable source names.
Any rough ideas/caveats with this one?

After playing with this plugin and diving into the source I've finally figured out why this did not work for me. I'm using PHP and the PHP debug adapter (https://github.com/xdebug/vscode-php-debug/) does not support supportsCompletionsRequest.

When it does not support the completions request I assume the plugin should just do nothing but it gives the following error:

Error executing vim.schedule lua callback: ...e/pack/packer/start/cmp-buffer/lua/cmp_buffer/buffer.lua:356: bad argument #1 to 'ipairs' (table expected, got userdata)
stack traceback:
        [C]: in function 'ipairs'
        ...e/pack/packer/start/cmp-buffer/lua/cmp_buffer/buffer.lua:356: in function 'rebuild_unique_words'
        ...e/pack/packer/start/cmp-buffer/lua/cmp_buffer/buffer.lua:341: in function 'get_words'
        ...e/pack/packer/start/cmp-buffer/lua/cmp_buffer/source.lua:66: in function ''
        vim/_editor.lua: in function ''
        vim/_editor.lua: in function <vim/_editor.lua:0>

It happens sometimes when I type in the REPL window. When I disable the plugin, the error is gone.

Hello!
I am using nvim-dap with your nvim-dap-ui and lately also tried cmp-dap. I really like it, thank you!

Without cmp-dap, the repl buffer automatically closes when toggling/closing the dap-ui. The corresponding issue was raised here. Your workaround in this comment and your PR in nvim-dap both worked.
Now, after I included cmp-dap, the issue reappears. Could you imagine whether this is due to cmp-dap?

I'm on latest daily nvim build. And latest cmp. O get this error in dap-repl:

Any ideas how to fix it?

After installing cmp-dap, when I try to open Telescope for the first time in an nvim session, the Telescope prompt immediately closes. Subsequent attempts to open Telescope work fine, but it is annoying to get buggy behavior on the first attempt.

I fixed this by using the following enabled function instead of the one given in the README:

enabled = function()
  local disabled = false
  disabled = disabled or (vim.api.nvim_buf_get_option(0, 'buftype') == 'prompt'
      and not require("cmp_dap").is_dap_buffer())
  disabled = disabled or (vim.fn.reg_recording() ~= '')
  disabled = disabled or (vim.fn.reg_executing() ~= '')
  return not disabled
end,

The enabled function above is the default enabled function of nvim-cmp, with the only exception that this line

disabled = disabled or (vim.api.nvim_buf_get_option(0, 'buftype') == 'prompt')

was replaced with this line

disabled = disabled or (vim.api.nvim_buf_get_option(0, 'buftype') == 'prompt'
    and not require("cmp_dap").is_dap_buffer())

I suggest to update the README with the above enabled function instead of the current one, which is causing the issue I described earlier with Telescope (and probably other "prompt" buftypes).

In this commit, some suggested configuration from the readme was removed:
e21f0e5#diff-b335630551682c19a781afebcf4d07bf978fb1f8ac04c6bf87428ed5106870f5L8-L13

-- nvim-cmp by defaults disables autocomplete for prompt buffers

Completions weren't working for me until I added that configuration.