From c1e60f36f3fb915bb59503dedd330addb63161ac Mon Sep 17 00:00:00 2001
From: Nicknamess96 <113626193+Nicknamess96@users.noreply.github.com>
Date: Sat, 28 Feb 2026 15:59:53 +0100
Subject: [PATCH] fix(difftool): don't reset quickfix list when closing
 quickfix window #38088

Closing the quickfix window previously triggered a WinClosed autocmd
that deleted all difftool autocmds and pushed an empty quickfix list,
making the difftool non-functional. Users who close the quickfix window
to gain screen real estate for viewing diffs had no way to continue
navigating entries.

Remove the qf_win tracking and its associated WinClosed autocmd so that
closing the quickfix window no longer tears down the difftool state.
Closing either diff window still performs full cleanup as before.

The BufWinEnter handler no longer passes with_qf to diff_files, so
navigating entries while the quickfix window is closed reuses the
existing diff layout without forcing a layout rebuild.

Fixes #37388
---
 .../dist/opt/nvim.difftool/lua/difftool.lua   | 24 ++-----------------
 test/functional/plugin/difftool_spec.lua      | 17 +++++++++++++
 2 files changed, 19 insertions(+), 22 deletions(-)

diff --git a/runtime/pack/dist/opt/nvim.difftool/lua/difftool.lua b/runtime/pack/dist/opt/nvim.difftool/lua/difftool.lua
index b40517e4f1..2e4562a6c5 100644
--- a/runtime/pack/dist/opt/nvim.difftool/lua/difftool.lua
+++ b/runtime/pack/dist/opt/nvim.difftool/lua/difftool.lua
@@ -28,7 +28,6 @@ local layout = {
   group = nil,
   left_win = nil,
   right_win = nil,
-  qf_win = nil,
 }
 
 local util = require('vim._core.util')
@@ -42,7 +41,6 @@ local function cleanup_layout(with_qf)
   end
   layout.left_win = nil
   layout.right_win = nil
-  layout.qf_win = nil
 
   if with_qf then
     vim.fn.setqflist({})
@@ -55,9 +53,8 @@ end
 local function setup_layout(with_qf)
   local left_valid = layout.left_win and vim.api.nvim_win_is_valid(layout.left_win)
   local right_valid = layout.right_win and vim.api.nvim_win_is_valid(layout.right_win)
-  local qf_valid = layout.qf_win and vim.api.nvim_win_is_valid(layout.qf_win)
 
-  if left_valid and right_valid and (not with_qf or qf_valid) then
+  if left_valid and right_valid then
     return false
   end
 
@@ -68,9 +65,6 @@ local function setup_layout(with_qf)
 
   if with_qf then
     vim.cmd('botright copen')
-    layout.qf_win = vim.api.nvim_get_current_win()
-  else
-    layout.qf_win = nil
   end
   vim.api.nvim_set_current_win(layout.right_win)
 
@@ -89,20 +83,6 @@ local function setup_layout(with_qf)
       cleanup_layout(with_qf)
     end,
   })
-  if with_qf then
-    vim.api.nvim_create_autocmd('WinClosed', {
-      group = layout.group,
-      pattern = tostring(layout.qf_win),
-      callback = function()
-        -- For quickfix also close one of diff windows
-        if layout.left_win and vim.api.nvim_win_is_valid(layout.left_win) then
-          vim.api.nvim_win_close(layout.left_win, true)
-        end
-
-        cleanup_layout(with_qf)
-      end,
-    })
-  end
 end
 
 --- Diff two files
@@ -497,7 +477,7 @@ function M.open(left, right, opt)
 
       vim.w.lazyredraw = true
       vim.schedule(function()
-        diff_files(entry.user_data.left, entry.user_data.right, true)
+        diff_files(entry.user_data.left, entry.user_data.right)
         vim.w.lazyredraw = false
       end)
     end,
diff --git a/test/functional/plugin/difftool_spec.lua b/test/functional/plugin/difftool_spec.lua
index 87024c9abb..060a0414f2 100644
--- a/test/functional/plugin/difftool_spec.lua
+++ b/test/functional/plugin/difftool_spec.lua
@@ -98,4 +98,21 @@ describe('nvim.difftool', function()
     local ok = pcall(fn.nvim_get_autocmds, { group = 'nvim.difftool.events' })
     eq(false, ok)
   end)
+
+  it('does not reset quickfix list when closing quickfix window', function()
+    command(('DiffTool %s %s'):format(testdir_left, testdir_right))
+    local qflist_before = fn.getqflist()
+    assert(#qflist_before > 0, 'quickfix list should not be empty')
+
+    -- Close the quickfix window
+    command('cclose')
+
+    -- Quickfix list should still be intact
+    local qflist_after = fn.getqflist()
+    eq(#qflist_before, #qflist_after)
+
+    -- Autocmds should still be active
+    local autocmds = fn.nvim_get_autocmds({ group = 'nvim.difftool.events' })
+    assert(#autocmds > 0, 'autocmds should still exist after closing quickfix window')
+  end)
 end)