1 files changed, 31 insertions, 10 deletions

diff --git a/src/nvim/buffer.c b/src/nvim/buffer.c
index 9e781f5dff..3c416c157f 100644
--- a/src/nvim/buffer.c
+++ b/src/nvim/buffer.c
@@ -337,6 +337,10 @@ void close_buffer(win_T *win, buf_T *buf, int action, int abort_if_last)
   bool del_buf = (action == DOBUF_DEL || action == DOBUF_WIPE);
   bool wipe_buf = (action == DOBUF_WIPE);
 
+  bool is_curwin = (curwin != NULL && curwin->w_buffer == buf);
+  win_T *the_curwin = curwin;
+  tabpage_T *the_curtab = curtab;
+
   // Force unloading or deleting when 'bufhidden' says so, but not for terminal
   // buffers.
   // The caller must take care of NOT deleting/freeing when 'bufhidden' is
@@ -360,6 +364,13 @@ void close_buffer(win_T *win, buf_T *buf, int action, int abort_if_last)
     wipe_buf = true;
   }
 
+  // Disallow deleting the buffer when it is locked (already being closed or
+  // halfway a command that relies on it). Unloading is allowed.
+  if (buf->b_locked > 0 && (del_buf || wipe_buf)) {
+    EMSG(_("E937: Attempt to delete a buffer that is in use"));
+    return;
+  }
+
   if (win_valid_any_tab(win)) {
     // Set b_last_cursor when closing the last window for the buffer.
     // Remember the last cursor position and window options of the buffer.
@@ -378,14 +389,14 @@ void close_buffer(win_T *win, buf_T *buf, int action, int abort_if_last)
 
   /* When the buffer is no longer in a window, trigger BufWinLeave */
   if (buf->b_nwindows == 1) {
-    buf->b_closing = true;
+    buf->b_locked++;
     if (apply_autocmds(EVENT_BUFWINLEAVE, buf->b_fname, buf->b_fname, false,
                        buf) && !bufref_valid(&bufref)) {
       // Autocommands deleted the buffer.
       EMSG(_(e_auabort));
       return;
     }
-    buf->b_closing = false;
+    buf->b_locked--;
     if (abort_if_last && one_window()) {
       /* Autocommands made this the only window. */
       EMSG(_(e_auabort));
@@ -395,14 +406,14 @@ void close_buffer(win_T *win, buf_T *buf, int action, int abort_if_last)
     /* When the buffer becomes hidden, but is not unloaded, trigger
      * BufHidden */
     if (!unload_buf) {
-      buf->b_closing = true;
+      buf->b_locked++;
       if (apply_autocmds(EVENT_BUFHIDDEN, buf->b_fname, buf->b_fname, false,
                          buf) && !bufref_valid(&bufref)) {
         // Autocommands deleted the buffer.
         EMSG(_(e_auabort));
         return;
       }
-      buf->b_closing = false;
+      buf->b_locked--;
       if (abort_if_last && one_window()) {
         /* Autocommands made this the only window. */
         EMSG(_(e_auabort));
@@ -412,6 +423,16 @@ void close_buffer(win_T *win, buf_T *buf, int action, int abort_if_last)
     if (aborting())         /* autocmds may abort script processing */
       return;
   }
+
+  // If the buffer was in curwin and the window has changed, go back to that
+  // window, if it still exists.  This avoids that ":edit x" triggering a
+  // "tabnext" BufUnload autocmd leaves a window behind without a buffer.
+  if (is_curwin && curwin != the_curwin &&  win_valid_any_tab(the_curwin)) {
+    block_autocmds();
+    goto_tabpage_win(the_curtab, the_curwin);
+    unblock_autocmds();
+  }
+
   int nwindows = buf->b_nwindows;
 
   /* decrease the link count from windows (unless not in any window) */
@@ -559,7 +580,7 @@ void buf_freeall(buf_T *buf, int flags)
   tabpage_T *the_curtab = curtab;
 
   // Make sure the buffer isn't closed by autocommands.
-  buf->b_closing = true;
+  buf->b_locked++;
 
   bufref_T bufref;
   set_bufref(&bufref, buf);
@@ -584,7 +605,7 @@ void buf_freeall(buf_T *buf, int flags)
     // Autocommands may delete the buffer.
     return;
   }
-  buf->b_closing = false;
+  buf->b_locked--;
 
   // If the buffer was in curwin and the window has changed, go back to that
   // window, if it still exists.  This avoids that ":edit x" triggering a
@@ -1111,7 +1132,7 @@ do_buffer (
      * a window with this buffer.
      */
     while (buf == curbuf
-           && !(curwin->w_closing || curwin->w_buffer->b_closing)
+           && !(curwin->w_closing || curwin->w_buffer->b_locked > 0)
            && (firstwin != lastwin || first_tabpage->tp_next != NULL)) {
       if (win_close(curwin, FALSE) == FAIL)
         break;
@@ -4497,9 +4518,9 @@ void ex_buffer_all(exarg_T *eap)
                ? wp->w_height + wp->w_status_height < Rows - p_ch
                - tabline_height()
                : wp->w_width != Columns)
-           || (had_tab > 0 && wp != firstwin)
-           ) && firstwin != lastwin
-          && !(wp->w_closing || wp->w_buffer->b_closing)
+           || (had_tab > 0 && wp != firstwin))
+          && firstwin != lastwin
+          && !(wp->w_closing || wp->w_buffer->b_locked > 0)
           ) {
         win_close(wp, FALSE);
         wpnext = firstwin;              /* just in case an autocommand does