Crash in get_lsp_location_from_selection on Neovim v0.11+ due to missing offset_encoding

[artkpv]

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Describe the bug

Description
When using commands like ZkInsertLink (mapped to wil in some configs), the plugin crashes with the error:
Error executing Lua callback: vim/_editor.lua:0: s: expected string, got nil

Stack Trace

vim/_editor.lua: in function 'character_offset'
/usr/share/nvim/runtime/lua/vim/lsp/util.lua:2039: in function 'make_range_zk'
.../zk-nvim/lua/zk/util.lua:77: in function 'get_lsp_location_from_selection'
.../zk-nvim/lua/zk/commands/builtin.lua:83: in function 'insert_link'

**Cause**
Recent versions of Neovim (v0.10/v0.11+) strictly require the `offset_encoding` argument in `vim.lsp.util.make_given_range_params` to be a string.

In `lua/zk/util.lua`, the `get_offset_encoding` function has a logic error:

  elseif zk_client.offset_encoding == nil then
    vim.notify_once(...)
    -- MISSING: offset_encoding = "utf-16"
  else
    offset_encoding = zk_client.offset_encoding
  end
  return offset_encoding -- Returns nil!

When zk_client.offset_encoding is nil, the function returns nil, causing make_given_range_params to crash.

Suggested Fix
In lua/zk/util.lua:

elseif zk_client.offset_encoding == nil then
vim.notify_once(...)
offset_encoding = "utf-16" -- Add this line
else

How to reproduce?

For some buffers, when I press wil (insert a link)

zk configuration

❯ cat .zk/config.toml| grep -o '^[^#].*'
[note]
language = "en"
default-title = "Untitled"
filename = "{{id}}-{{slug title}}"
extension = "md"
template = "default.md"
exclude = [
    # Glob patterns are relative to the notebook root.

    # Hidden files and directories
    ".*",
    "**/.*",
    # Exclude specific directories and their contents recursively
    "bin",
    "bin/**",
    "assets",
    "assets/**",
    "files",
    "**/files",
    "**/files/**",
    "time",
    "time/**",
    # Specific system/tool directories
    ".aider",
    ".aider/**",
    ".app",
    ".claude",
    ".git",
    ".stfolder",
    ".stversions",
    ".vim",
    ".zettel-notes",
    ".zk",

    # Cache directories if needed (though covered by .*)
    ".aider.tags.cache.v3",
    ".aider.tags.cache.v4",
]
id-charset = "alphanum"
id-length = 4
id-case = "lower"
[extra]
[group.diary]
paths = [
	"2025",
	"2026",
	"2027",
	"2028",
]
[group.diary.note]
filename = "{{format-date now '%Y-%m-%d'}}-{{slug title}}"
template = "journal.md"
[format.markdown]
link-format = "markdown"
link-encode-path = true
link-drop-extension = false
hashtags = false
colon-tags = true
multiword-tags = false
[tool]
editor = "vim"
pager = "bat"
fzf-preview = "bat -p --color always {-1}"
[lsp]
[lsp.diagnostics]
dead-link = "none"
[lsp.completion]
[filter]
[alias]

Neovim configuration

With the fix I applied:


  {
    'zk-org/zk-nvim',
    config = function()
      require('zk').setup {

        -- Can be "telescope", "fzf", "fzf_lua", "minipick", "snacks_picker",
        -- or select" (`vim.ui.select`).
        picker = 'telescope',

        lsp = {
          -- `config` is passed to `vim.lsp.start(config)`
          config = {
            name = 'zk',
            cmd = { 'zk', 'lsp' },
            filetypes = { 'markdown' },
            -- on_attach = ...
            -- etc, see `:h vim.lsp.start()`
          },

          -- automatically attach buffers in a zk notebook that match the given filetypes
          auto_attach = {
            enabled = true,
          },
        },
      }

      -- HOTFIX: Patch zk.util to avoid crash on recent Neovim versions
      -- Issue: "s: expected string, got nil" in make_given_range_params
      local util = require('zk.util')
      
      util.get_lsp_location_from_selection = function()
        local bufnr = vim.api.nvim_get_current_buf()
        local encoding = 'utf-16'
        local client = vim.lsp.get_clients({ bufnr = bufnr, name = 'zk' })[1]
        if client and client.offset_encoding then
          encoding = client.offset_encoding
        end

        local params = vim.lsp.util.make_given_range_params(nil, nil, bufnr, encoding)
        return {
          uri = params.textDocument.uri,
          range = params.range,
        }
      end

      util.get_lsp_location_from_caret = function()
        local bufnr = vim.api.nvim_get_current_buf()
        local uri = vim.uri_from_bufnr(bufnr)
        local row, col = unpack(vim.api.nvim_win_get_cursor(0))
        
        -- Manual construction of range to avoid make_range_zk overhead/issues
        -- Logic matches original fix_cursor_location: line - 1, char + 1
        return {
          uri = uri,
          range = {
            start = { line = row - 1, character = col + 1 },
            ['end'] = { line = row - 1, character = col + 1 },
          },
        }
      end
    end,
  },

Environment

❯ zk --version && echo "system: `uname -srmo`" && nvim --version

zk 0.15.2
system: Linux 6.18.2-arch2-1 x86_64 GNU/Linux
NVIM v0.11.5
Build type: RelWithDebInfo
LuaJIT 2.1.1765228720
Run "nvim -V1 -v" for more info