feat(git): add status diff tab binding

plugins/vim-fugitive.lua

@@ -6,20 +6,45 @@ local function open_git_status()
     vim.api.nvim_set_current_win(previous_win)
 end
 
-local function get_git_status_win()
-    local current_tabpage = vim.api.nvim_get_current_tabpage()
-    for _, win in ipairs(vim.api.nvim_tabpage_list_wins(current_tabpage)) do
+---@param buf integer
+---@return boolean
+local function is_git_status_buffer(buf)
+    return vim.fn.getbufvar(buf, "fugitive_type") == "index"
+end
+
+---@param tabpage integer?
+---@return integer?
+local function get_git_status_win(tabpage)
+    tabpage = tabpage or vim.api.nvim_get_current_tabpage()
+    for _, win in ipairs(vim.api.nvim_tabpage_list_wins(tabpage)) do
         local buf = vim.api.nvim_win_get_buf(win)
-        local buftype = vim.api.nvim_get_option_value("buftype", { buf = buf })
-        if
-            buftype == "nowrite"
-            and vim.api.nvim_buf_get_name(buf):match("^fugitive://.*%.git//$")
-        then
+        if is_git_status_buffer(buf) then
             return win
         end
     end
 end
 
+local function git_status_diffsplit()
+    local status_win = vim.api.nvim_get_current_win()
+    local ok, err = pcall(function()
+        vim.api.nvim_win_call(status_win, function()
+            vim.cmd("normal dv")
+        end)
+    end)
+    if not ok then
+        error(err, 0)
+    end
+end
+
+---@param args vim.api.keyset.create_autocmd.callback_args
+local function on_git_status(args)
+    vim.keymap.set("n", "<Tab>", git_status_diffsplit, {
+        buffer = args.buf,
+        desc = "Open file diff without changing focus",
+        silent = true,
+    })
+end
+
 local function toggle_git_status()
     local win = get_git_status_win()
     if win then
@@ -35,6 +60,11 @@ vim.api.nvim_create_user_command(
     { desc = "Toggle fugitive git status window" }
 )
 
+vim.api.nvim_create_autocmd("User", {
+    pattern = "FugitiveIndex",
+    callback = on_git_status,
+})
+
 vim.api.nvim_create_user_command("Glog", function(opts)
     local mods = opts.mods ~= "" and (opts.mods .. " ") or ""
     vim.cmd(