feat: add vscode-diff.nvim as alternative diff viewer

Add support for vscode-diff.nvim alongside diffview.nvim for viewing
diffs. Users can explicitly choose via the new `diff_viewer` config
option, or let Neogit auto-detect (diffview first, then vscode-diff).

Why:

- Provides choice for users who prefer vscode-diff's interface
- Maintains backwards compatibility (diffview remains default)
- Auto-detection means zero config for most users

Implementation:

- New `diff_viewer` config option: "diffview", "vscode_diff", or nil
- New integration module at integrations/vscode-diff.lua with same
  interface as diffview (M.open with section_name, item_name, opts)
- get_diff_viewer() helper handles explicit choice vs auto-detection
- Diff popup and status buffer conflict resolution dispatch to the
  configured viewer
- on_close callback for auto-staging after conflict resolution works
  with both viewers using the same BufEnter autocmd pattern

Author: sotte

README.md

@@ -33,7 +33,10 @@ Here's an example spec for [Lazy](https://github.com/folke/lazy.nvim), but you'r
   lazy = true,
   dependencies = {
     "nvim-lua/plenary.nvim",         -- required
-    "sindrets/diffview.nvim",        -- optional - Diff integration
+
+    -- Only one of these is needed.
+    "sindrets/diffview.nvim",        -- optional
+    "ldelossa/vscode-diff.nvim",     -- optional
 
     -- Only one of these is needed.
     "nvim-telescope/telescope.nvim", -- optional
@@ -319,6 +322,10 @@ neogit.setup {
     -- Requires you to have `sindrets/diffview.nvim` installed.
     diffview = nil,
 
+    -- Alternative diff viewer integration.
+    -- Requires you to have `ldelossa/vscode-diff.nvim` installed.
+    vscode_diff = nil,
+
     -- If enabled, uses fzf-lua for menu selection. If the telescope integration
     -- is also selected then telescope is used instead
     -- Requires you to have `ibhagwan/fzf-lua` installed.
@@ -334,6 +341,9 @@ neogit.setup {
     -- Requires you to have `folke/snacks.nvim` installed.
     snacks = nil,
   },
+  -- Which diff viewer to use. nil = auto-detect (tries diffview first, then vscode_diff).
+  -- Can be "diffview" or "vscode_diff".
+  diff_viewer = nil,
   sections = {
     -- Reverting/Cherry Picking
     sequencer = {

doc/neogit.txt

@@ -285,6 +285,10 @@ to Neovim users.
         -- Requires you to have `sindrets/diffview.nvim` installed.
         diffview = nil,
 
+        -- Alternative diff viewer integration.
+        -- Requires you to have `ldelossa/vscode-diff.nvim` installed.
+        vscode_diff = nil,
+
         -- If enabled, uses fzf-lua for menu selection. If the telescope integration
         -- is also selected then telescope is used instead
         -- Requires you to have `ibhagwan/fzf-lua` installed.
@@ -300,6 +304,9 @@ to Neovim users.
         -- Requires you to have `folke/snacks.nvim` installed.
         snacks = nil,
     },
+    -- Which diff viewer to use. nil = auto-detect (tries diffview first, then vscode_diff).
+    -- Can be "diffview" or "vscode_diff".
+    diff_viewer = nil,
     sections = {
         -- Reverting/Cherry Picking
         sequencer = {
@@ -1401,9 +1408,13 @@ The diff popup actions allow inspection of changes in the index (staged
 changes), the working tree (unstaged changes and untracked files), any
 ref range.
 
-For these actions to become available, Neogit needs to be configured to enable
-`diffview.nvim` integration. See |neogit_setup_plugin| and
-https://github.com/sindrets/diffview.nvim.
+For these actions to become available, Neogit needs to have a diff viewer
+integration enabled. Supported viewers are:
+- `diffview.nvim`: https://github.com/sindrets/diffview.nvim
+- `vscode-diff.nvim`: https://github.com/ldelossa/vscode-diff.nvim
+
+By default, Neogit will auto-detect which viewer is available. You can
+explicitly set the viewer with the `diff_viewer` option. See |neogit_setup_plugin|.
 
   • Diff this                                                 *neogit_diff_this*
     Show the diff for the file referred to by a hunk under the cursor.

lua/neogit/buffers/status/actions.lua

@@ -1145,8 +1145,12 @@ M.n_stage = function(self)
       end
 
       if selection.item and selection.item.mode == "UU" then
-        if config.check_integration("diffview") and git.merge.is_conflicted(selection.item.escaped_path) then
-          require("neogit.integrations.diffview").open("conflict", selection.item.name, {
+        local diff_viewer = config.get_diff_viewer()
+        if diff_viewer and git.merge.is_conflicted(selection.item.escaped_path) then
+          local integration = diff_viewer == "vscode_diff"
+            and require("neogit.integrations.vscode-diff")
+            or require("neogit.integrations.diffview")
+          integration.open("conflict", selection.item.name, {
             on_close = {
               handle = self.buffer.handle,
               fn = function()
@@ -1186,8 +1190,12 @@ M.n_stage = function(self)
         self:dispatch_refresh({ update_diffs = { "untracked:*" } }, "n_stage")
       elseif section.options.section == "unstaged" then
         if git.status.any_unmerged() then
-          if config.check_integration("diffview") then
-            require("neogit.integrations.diffview").open("conflict", nil, {
+          local diff_viewer = config.get_diff_viewer()
+          if diff_viewer then
+            local integration = diff_viewer == "vscode_diff"
+              and require("neogit.integrations.vscode-diff")
+              or require("neogit.integrations.diffview")
+            integration.open("conflict", nil, {
               on_close = {
                 handle = self.buffer.handle,
                 fn = function()

lua/neogit/config.lua

@@ -387,7 +387,8 @@ end
 ---@field preview_buffer? NeogitConfigPopup Preview options
 ---@field popup? NeogitConfigPopup Set the default way of opening popups
 ---@field signs? NeogitConfigSigns Signs used for toggled regions
----@field integrations? { diffview: boolean, telescope: boolean, fzf_lua: boolean, mini_pick: boolean, snacks: boolean } Which integrations to enable
+---@field integrations? { diffview: boolean, vscode_diff: boolean, telescope: boolean, fzf_lua: boolean, mini_pick: boolean, snacks: boolean } Which integrations to enable
+---@field diff_viewer? "diffview"|"vscode_diff"|nil Which diff viewer to use (nil = auto-detect)
 ---@field sections? NeogitConfigSections
 ---@field ignored_settings? string[] Settings to never persist, format: "Filetype--cli-value", i.e. "NeogitCommitPopup--author"
 ---@field mappings? NeogitConfigMappings
@@ -540,10 +541,12 @@ function M.get_default_values()
     integrations = {
       telescope = nil,
       diffview = nil,
+      vscode_diff = nil,
       fzf_lua = nil,
       mini_pick = nil,
       snacks = nil,
     },
+    diff_viewer = nil,
     sections = {
       sequencer = {
         folded = false,
@@ -856,8 +859,26 @@ function M.validate_config()
     end
   end
 
+  local function validate_diff_viewer()
+    if config.diff_viewer == nil then
+      return
+    end
+
+    local valid_viewers = { "diffview", "vscode_diff" }
+    if not vim.tbl_contains(valid_viewers, config.diff_viewer) then
+      err(
+        "diff_viewer",
+        string.format(
+          "Expected diff_viewer to be one of %s or nil, got '%s'",
+          table.concat(valid_viewers, ", "),
+          tostring(config.diff_viewer)
+        )
+      )
+    end
+  end
+
   local function validate_integrations()
-    local valid_integrations = { "diffview", "telescope", "fzf_lua", "mini_pick", "snacks" }
+    local valid_integrations = { "diffview", "vscode_diff", "telescope", "fzf_lua", "mini_pick", "snacks" }
     if not validate_type(config.integrations, "integrations", "table") or #config.integrations == 0 then
       return
     end
@@ -1277,6 +1298,7 @@ function M.validate_config()
     end
 
     validate_integrations()
+    validate_diff_viewer()
     validate_sections()
     validate_ignored_settings()
     validate_mappings()
@@ -1308,6 +1330,32 @@ function M.check_integration(name)
   return enabled
 end
 
+---Returns the configured diff viewer, or auto-detects if not set
+---@return string|nil The diff viewer to use ("diffview", "vscode_diff"), or nil if none available
+function M.get_diff_viewer()
+  local logger = require("neogit.logger")
+  local viewer = M.values.diff_viewer
+
+  if viewer then
+    -- Explicit choice - verify it's available
+    if M.check_integration(viewer) then
+      return viewer
+    else
+      logger.warn(("[CONFIG] Configured diff_viewer '%s' is not available"):format(viewer))
+      return nil
+    end
+  end
+
+  -- Auto-detect: try diffview first (backwards compatible), then vscode_diff
+  if M.check_integration("diffview") then
+    return "diffview"
+  elseif M.check_integration("vscode_diff") then
+    return "vscode_diff"
+  end
+
+  return nil
+end
+
 function M.setup(opts)
   if opts == nil then
     return