From e002e4d7fceeac91adb57bf00bb23e383447c99f Mon Sep 17 00:00:00 2001
From: Sean Dewar <6256228+seandewar@users.noreply.github.com>
Date: Thu, 8 Jan 2026 21:37:58 +0000
Subject: [PATCH] vim-patch:9.1.2068: :bd/bw may try to switch to a closing
 buffer

Problem:  :bdelete/bunload/bwipeout may attempt to switch to a closing
          buffer, which fails. (after 9.1.2058)
Solution: don't consider switching to closing buffers (Sean Dewar)

closes: vim/vim#19107

https://github.com/vim/vim/commit/63d53de72d94b53172070acb2b1c50489d1133bd

Co-authored-by: Sean Dewar <6256228+seandewar@users.noreply.github.com>
---
 src/nvim/buffer.c                |  17 ++--
 test/old/testdir/test_buffer.vim | 146 +++++++++++++++++++++++++++++++
 2 files changed, 156 insertions(+), 7 deletions(-)

diff --git a/src/nvim/buffer.c b/src/nvim/buffer.c
index 47ab7c8d43..4b94a1eb8f 100644
--- a/src/nvim/buffer.c
+++ b/src/nvim/buffer.c
@@ -1434,10 +1434,11 @@ static int do_buffer_ext(int action, int start, int dir, int count, int flags)
     // Then prefer the buffer we most recently visited.
     // Else try to find one that is loaded, after the current buffer,
     // then before the current buffer.
-    // Finally use any buffer.
+    // Finally use any buffer.  Skip buffers that are closing throughout.
     buf = NULL;  // Selected buffer.
     bp = NULL;   // Used when no loaded buffer found.
-    if (au_new_curbuf.br_buf != NULL && bufref_valid(&au_new_curbuf)) {
+    if (au_new_curbuf.br_buf != NULL && bufref_valid(&au_new_curbuf)
+        && !au_new_curbuf.br_buf->b_locked_split) {
       buf = au_new_curbuf.br_buf;
     } else if (curwin->w_jumplistlen > 0) {
       if (jop_flags & kOptJopFlagClean) {
@@ -1469,8 +1470,9 @@ static int do_buffer_ext(int action, int start, int dir, int count, int flags)
 
           if (buf != NULL) {
             // Skip current and unlisted bufs.  Also skip a quickfix
-            // buffer, it might be deleted soon.
-            if (buf == curbuf || !buf->b_p_bl || bt_quickfix(buf)) {
+            // or closing buffer, it might be deleted soon.
+            if (buf == curbuf || !buf->b_p_bl || bt_quickfix(buf)
+                || buf->b_locked_split) {
               buf = NULL;
             } else if (buf->b_ml.ml_mfp == NULL) {
               // skip unloaded buf, but may keep it for later
@@ -1514,7 +1516,8 @@ static int do_buffer_ext(int action, int start, int dir, int count, int flags)
           continue;
         }
         // in non-help buffer, try to skip help buffers, and vv
-        if (buf->b_help == curbuf->b_help && buf->b_p_bl && !bt_quickfix(buf)) {
+        if (buf->b_help == curbuf->b_help && buf->b_p_bl
+            && !bt_quickfix(buf) && !buf->b_locked_split) {
           if (buf->b_ml.ml_mfp != NULL) {           // found loaded buffer
             break;
           }
@@ -1530,7 +1533,7 @@ static int do_buffer_ext(int action, int start, int dir, int count, int flags)
     }
     if (buf == NULL) {          // No loaded buffer, find listed one
       FOR_ALL_BUFFERS(buf2) {
-        if (buf2->b_p_bl && buf2 != curbuf && !bt_quickfix(buf2)) {
+        if (buf2->b_p_bl && buf2 != curbuf && !bt_quickfix(buf2) && !buf2->b_locked_split) {
           buf = buf2;
           break;
         }
@@ -1538,7 +1541,7 @@ static int do_buffer_ext(int action, int start, int dir, int count, int flags)
     }
     if (buf == NULL) {          // Still no buffer, just take one
       buf = curbuf->b_next != NULL ? curbuf->b_next : curbuf->b_prev;
-      if (bt_quickfix(buf)) {
+      if (bt_quickfix(buf) || (buf != curbuf && buf->b_locked_split)) {
         buf = NULL;
       }
     }
diff --git a/test/old/testdir/test_buffer.vim b/test/old/testdir/test_buffer.vim
index ac6def23a9..765faca2f6 100644
--- a/test/old/testdir/test_buffer.vim
+++ b/test/old/testdir/test_buffer.vim
@@ -736,4 +736,150 @@ func Test_switch_to_previously_viewed_buffer()
   set startofline&
 endfunc
 
+func Test_bdelete_skip_closing_bufs()
+  set hidden
+  let s:fired = 0
+
+  edit foo
+  edit bar
+  let s:next_new_bufnr = bufnr('$') + 1
+  augroup SkipClosing
+    autocmd!
+    " Only window and other buffer is closing.
+    " No choice but to switch to a new, empty buffer.
+    autocmd BufDelete * ++once let s:fired += 1
+          \| call assert_equal(1, winnr('$'))
+          \| call assert_equal('bar', bufname())
+          \| bdelete
+          \| call assert_equal('', bufname())
+          \| call assert_equal(s:next_new_bufnr, bufnr())
+  augroup END
+  bdelete foo
+  call assert_equal(1, s:fired)
+  unlet! s:next_new_bufnr
+  %bw!
+
+  edit baz
+  edit bar
+  edit fleb
+  edit foo
+  augroup SkipClosing
+    autocmd!
+    " Only window, au_new_curbuf is NOT closing; should end up there.
+    autocmd BufDelete * ++once let s:fired += 1
+          \| call assert_equal(1, winnr('$'))
+          \| call assert_equal('foo', bufname())
+          \| bwipeout
+          \| call assert_equal('bar', bufname())
+  augroup END
+  buffer baz
+  buffer foo
+  augroup SkipClosing
+    autocmd BufLeave * ++once ++nested bdelete baz
+  augroup END
+  edit bar
+  call assert_equal(2, s:fired)
+  %bw!
+
+  edit baz
+  edit bar
+  edit fleb
+  edit foo
+  augroup SkipClosing
+    autocmd!
+    " Like above, but au_new_curbuf IS closing.
+    " Should use the most recent jumplist buffer instead.
+    autocmd BufDelete * ++once let s:fired += 1
+          \| call assert_equal(1, winnr('$'))
+          \| call assert_equal('foo', bufname())
+          \| bwipeout
+          \| call assert_equal('baz', bufname())
+  augroup END
+  buffer baz
+  buffer foo
+  augroup SkipClosing
+    autocmd BufLeave * ++once ++nested bdelete bar
+  augroup END
+  edit bar
+  call assert_equal(3, s:fired)
+  %bw!
+
+  edit foo
+  edit floob
+  edit baz
+  edit bar
+  augroup SkipClosing
+    autocmd!
+    " Only window, most recent buffer in jumplist is closing.
+    " Should switch to the next most-recent buffer in the jumplist instead.
+    autocmd BufDelete * ++once let s:fired += 1
+          \| call assert_equal(1, winnr('$'))
+          \| call assert_equal('bar', bufname())
+          \| bdelete
+          \| call assert_equal('floob', bufname())
+  augroup END
+  buffer baz
+  buffer floob
+  buffer foo
+  buffer bar
+  bdelete foo
+  call assert_equal(4, s:fired)
+  %bw!
+
+  edit foo
+  edit baz
+  edit bar
+  edit floob
+  edit bazinga
+  augroup SkipClosing
+    autocmd!
+    " Only window, most recent jumplist buffer is gone, next most-recent is
+    " closing.  Should switch to the 3rd most-recent jumplist buffer.
+    autocmd BufDelete * ++once let s:fired += 1
+          \| call assert_equal(1, winnr('$'))
+          \| call assert_equal('bar', bufname())
+          \| bwipeout
+          \| call assert_equal('baz', bufname())
+  augroup END
+  buffer bazinga
+  buffer baz
+  buffer floob
+  buffer foo
+  buffer bar
+  noautocmd bdelete foo
+  bdelete floob
+  call assert_equal(5, s:fired)
+  %bw!
+
+  edit foo
+  edit baz
+  edit floob
+  edit bazinga
+  edit bar
+  augroup SkipClosing
+    autocmd!
+    " Like above, but jumplist cleared, no next buffer in the buffer list and
+    " previous buffer is closing.  Should switch to the buffer before previous.
+    autocmd BufDelete * ++once let s:fired += 1
+          \| call assert_equal(1, winnr('$'))
+          \| call assert_equal('bar', bufname())
+          \| bunload
+          \| call assert_equal('floob', bufname())
+  augroup END
+  buffer bazinga
+  buffer baz
+  buffer floob
+  buffer foo
+  buffer bar
+  noautocmd bdelete foo
+  clearjumps
+  bdelete bazinga
+  call assert_equal(6, s:fired)
+
+  unlet! s:fired
+  autocmd! SkipClosing
+  set hidden&
+  %bw!
+endfunc
+
 " vim: shiftwidth=2 sts=2 expandtab