fix(window): custom border not work (#157)

use `vim.opt.winborder' as float window border

with `vim.opt.winborder = 'rounded'`

before:
<img width="3780" height="2112" alt="CleanShot 2025-07-22 at 13 48
04@2x"
src="https://github.com/user-attachments/assets/92fceab3-6f8b-4698-a887-1c7d8722a781"
/>

after:
<img width="3768" height="2102" alt="CleanShot 2025-07-22 at 13 47
19@2x"
src="https://github.com/user-attachments/assets/efbc5537-63fe-4a59-aebb-f603ffb1dc00"
/>

lua/lazygit/window.lua

@@ -33,42 +33,16 @@ local function open_floating_window()
     return plenary_win, plenary_buf
   end
 
-  local border_opts = {
+  local opts = {
-    style = 'minimal',
+    style = "minimal",
-    relative = 'editor',
+    relative = "editor",
-    row = row - 1,
+    row = row,
-    col = col - 1,
+    col = col,
-    width = width + 2,
+    width = width,
-    height = height + 2,
+    height = height,
+    border = vim.g.lazygit_floating_window_border_chars,
   }
 
-  local opts = { style = 'minimal', relative = 'editor', row = row, col = col, width = width, height = height }
-
-  local topleft, top, topright, right, botright, bot, botleft, left
-  local window_chars = vim.g.lazygit_floating_window_border_chars
-  if type(window_chars) == 'table' and #window_chars == 8 then
-    topleft, top, topright, right, botright, bot, botleft, left = unpack(window_chars)
-  else
-    topleft, top, topright, right, botright, bot, botleft, left = '╭', '─', '╮', '│', '╯', '─', '╰', '│'
-  end
-
-  local border_lines = { topleft .. string.rep(top, width) .. topright }
-  local middle_line = left .. string.rep(' ', width) .. right
-  for _ = 1, height do
-    table.insert(border_lines, middle_line)
-  end
-  table.insert(border_lines, botleft .. string.rep(bot, width) .. botright)
-
-  -- create a unlisted scratch buffer for the border
-  local border_buffer = api.nvim_create_buf(false, true)
-
-  -- set border_lines in the border buffer from start 0 to end -1 and strict_indexing false
-  api.nvim_buf_set_lines(border_buffer, 0, -1, true, border_lines)
-  -- create border window
-  local border_window = api.nvim_open_win(border_buffer, true, border_opts)
-  vim.api.nvim_set_hl(0, "LazyGitBorder", { link = "Normal", default = true })
-  vim.cmd('set winhl=NormalFloat:LazyGitBorder')
-
   -- create a unlisted scratch buffer
   if LAZYGIT_BUFFER == nil or vim.fn.bufwinnr(LAZYGIT_BUFFER) == -1 then
     LAZYGIT_BUFFER = api.nvim_create_buf(false, true)
@@ -76,37 +50,38 @@ local function open_floating_window()
     LAZYGIT_LOADED = true
   end
 
-  vim.cmd('setlocal signcolumn=no')
   -- create file window, enter the window, and use the options defined in opts
   local win = api.nvim_open_win(LAZYGIT_BUFFER, true, opts)
 
   vim.bo[LAZYGIT_BUFFER].filetype = 'lazygit'
 
-  vim.cmd('setlocal bufhidden=hide')
+  vim.bo.bufhidden = 'hide'
-  vim.cmd('setlocal nocursorcolumn')
+  vim.wo.cursorcolumn = false
-  vim.cmd('setlocal signcolumn=no')
+  vim.wo.signcolumn = 'no'
+  vim.api.nvim_set_hl(0, "LazyGitBorder", { link = "Normal", default = true })
   vim.api.nvim_set_hl(0, "LazyGitFloat", { link = "Normal", default = true })
-  vim.cmd('setlocal winhl=NormalFloat:LazyGitFloat')
+  vim.wo.winhl = 'FloatBorder:LazyGitBorder,NormalFloat:LazyGitFloat'
-  vim.cmd('set winblend=' .. vim.g.lazygit_floating_window_winblend)
+  vim.wo.winblend = vim.g.lazygit_floating_window_winblend
 
-  -- use autocommand to ensure that the border_buffer closes at the same time as the main buffer
-  local cmd = [[autocmd WinLeave <buffer> silent! execute 'hide']]
-  vim.cmd(cmd)
-  cmd = [[autocmd WinLeave <buffer> silent! execute 'silent bdelete! %s']]
-  vim.cmd(cmd:format(border_buffer))
   vim.api.nvim_create_autocmd('VimResized', {
     callback = function()
       vim.defer_fn(function()
-        if not vim.api.nvim_win_is_valid(border_window) then
+        if not vim.api.nvim_win_is_valid(win) then
           return
         end
         local new_width, new_height, new_row, new_col = get_window_pos()
-        api.nvim_win_set_config(border_window,
+        api.nvim_win_set_config(
-          { width = new_width + 2, height = new_height + 2, relative = 'editor', row = new_row - 1, col = new_col - 1, })
+          win,
-        api.nvim_win_set_config(win,
+          {
-          { width = new_width, height = new_height, relative = 'editor', row = new_row, col = new_col, })
+            width = new_width,
+            height = new_height,
+            relative = "editor",
+            row = new_row,
+            col = new_col,
+          }
+        )
       end, 20)
-    end
+    end,
   })
 
   return win, LAZYGIT_BUFFER