hunk.nvim

A tool for splitting diffs in Neovim

This is a Neovim tool for splitting/editing diffs. It operates over a left and right directory, producing a diff of the two which can subsequently be inspected and modified. The DiffEditor allows selecting changes by file, hunk or individual line to produce a new partial diff.

This was primarily built to be used with jujutsu as an alternative diff-editor to it's :builtin option, but it's designed generically enough that it can be used for other use cases.

To use it you need to give it two to three directories: a left, a right, and optionally a output directory. These directories will then be read in and used to produce a set of diffs between the two directories. You will then be presented with the left and right side of each file and can select the lines from each diff hunk you would like to keep.

When you are happy with your selection you can accept changes and the diff editor will modify the output directory (or the right directory if no output is provided) to match your selection.

Installation

Using folke/lazy.vim

{
  "julienvincent/hunk.nvim",
  cmd = { "DiffEditor" },
  config = function()
    require("hunk").setup()
  end,
}

Dependencies

• nui.nvim
• nvim-web-devicons (optional)
• mini.icons (optional)

If you want file type icons in the file tree then you should have one of either mini.icons or nvim-web-devicons installed. Otherwise, neither are required.

Configuration

local hunk = require("hunk")
hunk.setup({
  keys = {
    global = {
      quit = { "q" },
      accept = { "<leader><Cr>" },
      focus_tree = { "<leader>e" },
    },

    tree = {
      expand_node = { "l", "<Right>" },
      collapse_node = { "h", "<Left>" },

      open_file = { "<Cr>" },

      toggle_file = { "a" },
    },

    diff = {
      toggle_hunk = { "A" },
      toggle_line = { "a" },
      -- This is like toggle_line but it will also toggle the line on the other
      -- 'side' of the diff.
      toggle_line_pair = { "s" },

      prev_hunk = { "[h" },
      next_hunk = { "]h" },

      -- Jump between the left and right diff view
      toggle_focus = { "<Tab>" },
    },
  },

  ui = {
    tree = {
      -- Mode can either be `nested` or `flat`
      mode = "nested",
      width = 35,
    },
    --- Can be either `vertical` or `horizontal`
    layout = "vertical",
  },

  icons = {
    selected = "󰡖",
    deselected = "",
    partially_selected = "󰛲",

    folder_open = "",
    folder_closed = "",
  },

  -- Called right after each window and buffer are created.
  hooks = {
    ---@param _context { buf: number, tree: NuiTree, opts: table }
    on_tree_mount = function(_context) end,
    ---@param _context { buf: number, win: number }
    on_diff_mount = function(_context) end,
  },
})

Note

You can always press g? to get a help menu of the available commands

Accepting / Rejecting Changes

Once you are happy with your selected set of hunks and/or lines you can accept the change by using the key.global.accept keybinding. See configuration or press g? to see what this is bound to (default <leader><Cr>).

If Neovim exits with a non-0 exit code then the selection will be aborted and no changes will be written. You can use the keys.global.quit keybinding (default q) to exit with a non-0 exit code. This just calls :cq internally - so you can do that too.

Highlights

Most of the hunk colors can be configured by defining your own highlight overrides. Refer to the below table for a list of available highlights:

Highlight	Default
HunkTreeFileAdded	Green
HunkTreeFileDeleted	Red
HunkTreeFileModified	Blue
HunkTreeDirIcon	Yellow
HunkTreeSelectionIcon	Comment

Using Hooks

Hooks can be used to bind keys with "complex" logic, or to set buffer/window local options on the tree or diff splits.

Skipping Folders in the File Tree

These bindings allow j/k to skip over folders in the file tree (b/c they're generally not relevant). You can still access folders with gj/gk.

-- track all the lines of leaf nodes so we don't have to recompute them on each key press
local jumpable_lines
local function set_jumpabe_lines(context)
  jumpable_lines = {}
  local i = 1
  local n, _, _ = context.tree:get_node(i)
  while n do
    if not n:has_children() then
      table.insert(jumpable_lines, i)
    end
    i = i + 1
    n, _, _ = context.tree:get_node(i)
  end
end
require("hunk").setup({
  hooks = {
    on_tree_mount = function(context)
      vim.keymap.set("n", "j", function()
        -- unfortunately we have to recompute every time because folding ruins these computed values
        set_jumpabe_lines(context)
        local row = vim.api.nvim_win_get_cursor(0)[1]
        if row < jumpable_lines[1] then
          vim.api.nvim_win_set_cursor(0, { jumpable_lines[1], 0 })
          return
        end
        for idx = #jumpable_lines, 1, -1 do
          if jumpable_lines[idx] <= row then
            if jumpable_lines[idx + 1] then
              vim.api.nvim_win_set_cursor(0, { jumpable_lines[idx + 1], 0 })
            end
            return
          end
        end
      end, { buffer = context.buf })

      vim.keymap.set("n", "k", function()
        set_jumpabe_lines(context)
        local row = vim.api.nvim_win_get_cursor(0)[1]
        if row > jumpable_lines[#jumpable_lines] then
          vim.api.nvim_win_set_cursor(0, { jumpable_lines[#jumpable_lines], 0 })
          return
        end
        for idx, node_row in ipairs(jumpable_lines) do
          if node_row >= row then
            if jumpable_lines[idx - 1] then
              vim.api.nvim_win_set_cursor(0, { jumpable_lines[idx - 1], 0 })
            end
            return
          end
        end
      end, { buffer = context.buf })
    end,
  },
})

Set `nospell` in File Tree

require("hunk").setup({
  hooks = {
    on_tree_mount = function(context)
      vim.api.nvim_set_option_value("spell", false, { win = context.win })
    end,
  },
})

Using with Jujutsu

Jujutsu is an alternative VCS that has a focus on working with individual commits and their diffs.

A lot of commands in jujutsu allow you to select parts of a diff. The tool used to select the diff can be configured via their ui.diff-editor config option. To use hunk.nvim add the following to your jujutsu config.toml:

[ui]
diff-editor = ["nvim", "-c", "DiffEditor $left $right $output"]

You can find more info on this config in the jujutsu docs.