From e70452990935fedd7de6ca84dde4a0ac16807fd9 Mon Sep 17 00:00:00 2001
From: zeertzjq <zeertzjq@outlook.com>
Date: Sat, 7 Feb 2026 23:03:21 +0800
Subject: [PATCH] vim-patch:9.1.2136: :tab sbuffer may close old tabpage
 (#37765)

Problem:  :tab sbuffer may close old tabpage if BufLeave autocommand
          splits window (after 9.1.0143).
Solution: Only close other windows if the buffer will be unloaded
          (zeertzjq).

related: neovim/neovim#37749
closes: vim/vim#19352

https://github.com/vim/vim/commit/6da9f757c48ce87df381d726b165bed6fa301423
---
 src/nvim/buffer.c                 |  5 +++--
 test/old/testdir/test_autocmd.vim |  2 +-
 test/old/testdir/test_buffer.vim  | 33 +++++++++++++++++++++++++++++++
 3 files changed, 37 insertions(+), 3 deletions(-)

diff --git a/src/nvim/buffer.c b/src/nvim/buffer.c
index ba6e03a729..5a9939c0e6 100644
--- a/src/nvim/buffer.c
+++ b/src/nvim/buffer.c
@@ -1680,6 +1680,7 @@ void set_curbuf(buf_T *buf, int action, bool update_jumplist)
   bufref_T prevbufref;
   set_bufref(&prevbufref, prevbuf);
   set_bufref(&newbufref, buf);
+  const int prev_nwindows = prevbuf->b_nwindows;
 
   // Autocommands may delete the current buffer and/or the buffer we want to
   // go to.  In those cases don't close the buffer.
@@ -1692,8 +1693,8 @@ void set_curbuf(buf_T *buf, int action, bool update_jumplist)
     // autocommands may have opened a new window
     // with prevbuf, grr
     if (unload
-        || (last_winid != get_last_winid()
-            && strchr("wdu", prevbuf->b_p_bh[0]) != NULL)) {
+        || (prev_nwindows <= 1 && last_winid != get_last_winid()
+            && action == DOBUF_GOTO && !buf_hide(prevbuf))) {
       close_windows(prevbuf, false);
     }
     if (bufref_valid(&prevbufref) && !aborting()) {
diff --git a/test/old/testdir/test_autocmd.vim b/test/old/testdir/test_autocmd.vim
index b110b0f393..45dabcf4ce 100644
--- a/test/old/testdir/test_autocmd.vim
+++ b/test/old/testdir/test_autocmd.vim
@@ -4247,7 +4247,7 @@ func Test_autocmd_invalidates_undo_on_textchanged()
   call StopVimInTerminal(buf)
 endfunc
 
-func Test_autocmd_creates_new_buffer_on_bufleave()
+func Test_autocmd_creates_new_window_on_bufleave()
   e a.txt
   e b.txt
   setlocal bufhidden=wipe
diff --git a/test/old/testdir/test_buffer.vim b/test/old/testdir/test_buffer.vim
index 765faca2f6..997a952a14 100644
--- a/test/old/testdir/test_buffer.vim
+++ b/test/old/testdir/test_buffer.vim
@@ -882,4 +882,37 @@ func Test_bdelete_skip_closing_bufs()
   %bw!
 endfunc
 
+func Test_split_window_in_BufLeave_from_tab_sbuffer()
+  tabnew Xa
+  setlocal bufhidden=wipe
+  let t0 = tabpagenr()
+  let b0 = bufnr()
+  let b1 = bufadd('Xb')
+  autocmd BufLeave Xa ++once split
+  exe 'tab sbuffer' b1
+  call assert_equal(t0 + 1, tabpagenr())
+  call assert_equal([b1, b0], tabpagebuflist())
+  call assert_equal([b0], tabpagebuflist(t0))
+  tabclose
+  call assert_equal(t0, tabpagenr())
+  call assert_equal([b0], tabpagebuflist())
+
+  bwipe! Xa
+  bwipe! Xb
+endfunc
+
+func Test_split_window_in_BufLeave_from_switching_buffer()
+  tabnew Xa
+  setlocal bufhidden=wipe
+  split
+  let b0 = bufnr()
+  let b1 = bufadd('Xb')
+  autocmd BufLeave Xa ++once split
+  exe 'buffer' b1
+  call assert_equal([b1, b0, b0], tabpagebuflist())
+
+  bwipe! Xa
+  bwipe! Xb
+endfunc
+
 " vim: shiftwidth=2 sts=2 expandtab