bug: encode_selection_prompt in visual mode incorrectly captures selection -- Bad interaction with telescope-ui-select

[diegobit]

Did you check docs and existing issues?

• I have read all the docs
• I have searched the existing issues
• I have searched the existing issues of plugins related to this issue (if relevant)

Neovim version (nvim -v)

NVIM v0.11.7 - Release

Operating system/version

MacOS Tahoe 26.4

Describe the bug

I have require('decipher').encode_selection_prompt { preview = false } set in a keymap in visual mode:

vim.keymap.set('v', '<leader>ce', function()
  require('decipher').encode_selection_prompt { preview = false }
end, { desc = 'Encode Selected Text' })

but, when using it, nothing happens, unless I have previously set a selection.

If preview = true, then I get this error:

Error executing vim.schedule lua callback: .../share/nvim/lazy/decipher.nvim/lua/decipher/ui/float.lua:275: 'height' key must be a positive Integer
stack traceback:
        [C]: in function 'nvim_win_set_config'
        .../share/nvim/lazy/decipher.nvim/lua/decipher/ui/float.lua:275: in function 'render_page'
        .../share/nvim/lazy/decipher.nvim/lua/decipher/ui/float.lua:407: in function 'switch_to_page'
        .../share/nvim/lazy/decipher.nvim/lua/decipher/ui/float.lua:538: in function 'open'
        ...ocal/share/nvim/lazy/decipher.nvim/lua/decipher/init.lua:87: in function 'open_float_handler'
        ...ocal/share/nvim/lazy/decipher.nvim/lua/decipher/init.lua:135: in function 'process_codec'
        ...ocal/share/nvim/lazy/decipher.nvim/lua/decipher/init.lua:151: in function ''
        vim/_editor.lua: in function <vim/_editor.lua:0>

The plugin works with a minimal repro.lua, but doesn't with telescope-ui-select. Probably that plugin is not passing the selection to decipher? Not sure who the culprit is.

---

I attach a video as well

Screen.Recording.2026-04-01.at.09.21.57.mp4

---

Notes:

I'm using the most recent version of decipher from add-commands branch. Here's some info.

Lazy Log:

    ○ decipher.nvim 
        ba9ae0c Add tests for invalid command arguments (4 days ago)
        44d123d Remove print statement (5 days ago)
        459a13c Minor type fixes (5 days ago)
        33f1db4 Add commands (5 days ago)
        be80ebe Bump to v3.0.0 (#35) (6 weeks ago)
        adb89de Support writeback (#33) (9 weeks ago)
        2f511f2 Bump to v2.1.0 (#34) (6 months ago)
        9e92ebd Add codecs from vim-unimpaired (#30) (6 months ago)

Decipher config:

vim.keymap.set('n', '<leader>ce', function()
  require('decipher').encode_motion_prompt { preview = false }
end, { desc = 'Encode (w/ motion)' })
vim.keymap.set('n', '<leader>cd', function()
  require('decipher').decode_motion_prompt { preview = false }
end, { desc = 'Decode (w/ motion)' })
vim.keymap.set('v', '<leader>ce', function()
  require('decipher').encode_selection_prompt { preview = true }
end, { desc = 'Encode Selected Text' })
vim.keymap.set('v', '<leader>cd', function()
  require('decipher').decode_selection_prompt { preview = true }
end, { desc = 'Decode Selected Text' })

vim.keymap.set({ 'v' }, 'gbe', function()
  require('decipher').encode_selection ('base64', { preview = false })
  local keys = vim.api.nvim_replace_termcodes('<ESC>', true, false, true)
  vim.api.nvim_feedkeys(keys, 'm', false)
end, { noremap = true, silent = true, desc = 'Encode' })
vim.keymap.set({ 'v' }, 'gbd', function()
  require('decipher').decode_selection ('base64', { preview = false })
end, { noremap = true, silent = true, desc = 'Decode' })

vim.keymap.set({ 'v' }, 'gbse', function()
  require('decipher').encode_selection ('base64-url-safe', { preview = false })
end, { noremap = true, silent = true, desc = 'Encode' })
vim.keymap.set({ 'v' }, 'gbsd', function()
  require('decipher').decode_selection ('base64-url-safe', { preview = false })
end, { noremap = true, silent = true, desc = 'Decode' })

vim.keymap.set({ 'v' }, 'g/e', function()
  require('decipher').encode_selection ('url', { preview = false })
end, { noremap = true, silent = true, desc = 'Encode' })
vim.keymap.set({ 'v' }, 'g/d', function()
  require('decipher').decode_selection ('url', { preview = false })
end, { noremap = true, silent = true, desc = 'Decode' })

return {
  'MisanthropicBit/decipher.nvim',
  -- version = '*',
  branch = 'add-commands',
  -- event = 'VeryLazy',
  lazy = true, -- Load with keymap
  config = function()
    local decipher = require 'decipher'
    decipher.setup {
      active_codecs = 'all',
      float = {
        border = {
          { '┌', 'FloatBorder' },
          { '─', 'FloatBorder' },
          { '┐', 'FloatBorder' },
          { '│', 'FloatBorder' },
          { '┘', 'FloatBorder' },
          { '─', 'FloatBorder' },
          { '└', 'FloatBorder' },
          { '│', 'FloatBorder' },
        },

        mappings = {
          close = 'q',
          apply = 'y',
          jsonpp = 'J', -- Key to prettily format contents as json if possbile
          help = '?',
        },
        enter = true,
        options = {},
      },
    }
  end,
}

Output of :checkhealth decipher

==============================================================================
decipher: 1 ❌

• ❌ ERROR No healthcheck found for "decipher" plugin.

Steps To Reproduce

Steps to get empty behaviour:

1. nvim -u repro.lua
2. write anything*
3. visual mode, select some text (eg. word 'second')
4. trigger decipher keymap for encode_selection_prompt (base64)
5. nothing happens

Steps to see it's not getting the new selection:

1. nvim -u repro.lua
2. write anything*
3. visual mode, select some text (eg. word 'second')
4. , go back to normal mode
5. now visual mode, select some OTHER text (eg. word 'third')
6. trigger decipher keymap for encode_selection_prompt (base64)
7. the previously selected text gets encoded ('second' becomes 'c2Vjb25k')

*My example:

some text
on a second line
and a third line

Expected Behavior

Selected text in visual mode gets correctly encoded

Repro

local lazypath = vim.fn.stdpath("data") .. "/lazy/lazy.nvim"
if not vim.uv.fs_stat(lazypath) then
  vim.fn.system({
    "git",
    "clone",
    "--filter=blob:none",
    "https://github.com/folke/lazy.nvim.git",
    "--branch=stable",
    lazypath,
  })
end

vim.opt.rtp:prepend(lazypath)
vim.g.mapleader = " "

vim.keymap.set("v", "<leader>ce", function()
  require("decipher").encode_selection_prompt({ preview = false })
end, { desc = "Encode Selected Text" })

require("lazy").setup({
  {
    "nvim-telescope/telescope.nvim",
    dependencies = {
      "nvim-lua/plenary.nvim",
      "nvim-telescope/telescope-ui-select.nvim",
    },
    config = function()
      require("telescope").setup({
        extensions = {
          ["ui-select"] = require("telescope.themes").get_dropdown({}),
        },
      })

      pcall(require("telescope").load_extension, "ui-select")
    end,
  },
  {
    "MisanthropicBit/decipher.nvim",
    branch = "add-commands",
    lazy = true,
    config = function()
      require("decipher").setup({})
    end,
  },
})

[MisanthropicBit]

Awesome! 😄 thanks for providing such great detail. Thanks for the repro as well, I can reproduce it.

Good thing you found the interaction with telescope-ui-select.nvim. I would probably never have guessed that was the issue since I don't use it. Interestingly though I use the equivalent functionality of fzf-lua and that works fine. decipher.nvim is just calling vim.ui.select to allow custom behaviour as it was intended for.

I think the issue might be that either telescope-ui-select is breaking protocol when overriding vim.ui.select or decipher is not implementing it right (but it looks like it does). If an empty value is passed to the callback of vim.ui.select then the height calculation for the floating value will be zero since the number of lines is used to calculate the height of the float. I tried this out and if preview = true then telescope-ui-select passes an empty list of lines to decipher.

A few more things:

1. Remove all telescope dependencies from the repro and using vanilla vim.ui.select doesn't work...After selecting, nothing happens but the UI stays open. decipher gets the right codec, extracts the right content, from the right region for encoding/decoding. The problem seems to be that the visual mode detection doesn't work properly and detects the last visual mode.
2. Using my regular nvim config but without fzf-lua for vim.ui.select does work somehow.

I went and took a look at telescope-ui-select's source code and tried a few things but no luck so far. The last commit was 3 years ago though and there's only 15 commits in total which doesn't suggest that the plugin is stable but I'll keep looking to make sure it isn't decipher that is at fault.

decipher: 1 ❌

❌ ERROR No healthcheck found for "decipher" plugin.

I cannot reproduce this. Running :checkhealth decipher works for me (v0.11.5, on mac osx).

FYI, the behaviour with operating on the last selection is intentional.

[MisanthropicBit]

I did some more digging and found a bug that fixes the issue for vanilla vim.ui.select 🙂 #39.

Unfortunately the issue persists with telescope-ui-select.nvim. I tried some debugging but I can't get it to work so I'll unfortunately have to assume that the issue lies with telescope-ui-select.nvim. I haven't found another telescope-based alternative. On the other hand you probably have used the plugin for other things without issue so I can't be sure.

Let me know if there are other approaches I should take or you have more information on the issue.

[diegobit]

Same repro with your new version works for me.

On the other hand you probably have used the plugin for other things without issue so I can't be sure.

True...

A few days ago I tried keeping telescope, but removing ui-select and adding fzf-lua (diegobit/dotfiles@5173af4), and it was working.

Maybe it's not worth it to try and fix telescope-ui-select even though I see it's still present in the config I used when I started with neovim: kickstart. I haven't checked popular neovim distributions though.

As a side note, this issue convinced me to try replacing telescope completely with fzf-lua and I like it better!

[MisanthropicBit]

Same repro with your new version works for me.

Nice but what exactly works? With vanilla nvim?

Maybe it's not worth it to try and fix telescope-ui-select even though I see it's still present in the config I used when I started with neovim: kickstart. I haven't checked popular neovim distributions though.

That's also a bit out of scope for me at least.

As a side note, this issue convinced me to try replacing telescope completely with fzf-lua and I like it better!

I've personally used it for a very long time and been very happy with it. The maintainer is friendly and quick to respond and it is pretty straight-forward to extend. I also use fzf in the terminal so I already understand how the options work etc.

Can I close this issue then?

[diegobit]

Yes you can close!

Nice but what exactly works? With vanilla nvim?

I meant using my "broken" keymap under visual mode that executes require('decipher').encode_selection_prompt { preview = false }. As for nvim config I meant the repro file above