vim-patch:9.1.1773: Crash in BufLeave after BufUnload closes other windows (#35830)

Problem:  Crash in BufLeave/WinLeave/TabLeave when closing window after
          BufUnload closes all other windows in the tab page.
Solution: Avoid duplicate BufLeave/WinLeave events. Trigger TabLeave
          before removing the buffer (zeertzjq).

related: vim/vim#14166
related: neovim/neovim#33603
closes: vim/vim#18330

0c70820015
(cherry picked from commit c9f6267402)

src/nvim/window.c

@@ -2610,9 +2610,11 @@ static bool close_last_window_tabpage(win_T *win, bool free_buf, tabpage_T *prev
   // page and then close the window and the tab page.  This avoids that
   // curwin and curtab are invalid while we are freeing memory, they may
   // be used in GUI events.
-  // Don't trigger autocommands yet, they may use wrong values, so do
+  // Don't trigger *Enter autocommands yet, they may use wrong values, so do
   // that below.
-  goto_tabpage_tp(alt_tabpage(), false, true);
+  // Do trigger *Leave autocommands, unless win->w_buffer is NULL, in which
+  // case they have already been triggered.
+  goto_tabpage_tp(alt_tabpage(), false, win->w_buffer != NULL);
 
   // Safety check: Autocommands may have closed the window when jumping
   // to the other tab page.
@@ -2906,6 +2908,14 @@ int win_close(win_T *win, bool free_buf, bool force)
     }
   }
 
+  if (ONE_WINDOW && curwin->w_locked && curbuf->b_locked_split
+      && first_tabpage->tp_next != NULL) {
+    // The new curwin is the last window in the current tab page, and it is
+    // already being closed.  Trigger TabLeave now, as after its buffer is
+    // removed it's no longer safe to do that.
+    apply_autocmds(EVENT_TABLEAVE, NULL, NULL, false, curbuf);
+  }
+
   split_disallowed--;
 
   // After closing the help window, try restoring the window layout from

test/old/testdir/test_autocmd.vim

@@ -746,27 +746,49 @@ func Test_WinClosed_switch_tab()
   %bwipe!
 endfunc
 
-" This used to trigger WinClosed twice for the same window, and the window's
+" This used to trigger WinClosed/WinLeave/BufLeave twice for the same window,
-" buffer was NULL in the second autocommand.
+" and the window's buffer was NULL in the second autocommand.
-func Test_WinClosed_BufUnload_close_other()
+func Run_test_BufUnload_close_other(extra_cmd)
-  tabnew
+  let oldtab = tabpagenr()
+  tabnew Xb1
   let g:tab = tabpagenr()
-  let g:buf = bufnr()
+  let g:w1 = win_getid()
-  new
+  new Xb2
-  setlocal bufhidden=wipe
+  let g:w2 = win_getid()
-  augroup test-WinClosed
+  let g:log = []
-    autocmd BufUnload * ++once exe g:buf .. 'bwipe!'
+  exe a:extra_cmd
-    autocmd WinClosed * call tabpagebuflist(g:tab)
+
+  augroup test-BufUnload-close-other
+    autocmd BufUnload * ++nested ++once bwipe! Xb1
+    for event in ['WinClosed', 'BufLeave', 'WinLeave', 'TabLeave']
+      exe $'autocmd {event} * call tabpagebuflist(g:tab)'
+      exe $'autocmd {event} * let g:log += ["{event}:" .. expand("<afile>")]'
+    endfor
   augroup END
+
   close
+  " WinClosed is triggered once for each of the 2 closed windows.
+  " Others are only triggered once.
+  call assert_equal(['BufLeave:Xb2', 'WinLeave:Xb2', $'WinClosed:{g:w2}',
+        \ $'WinClosed:{g:w1}', 'TabLeave:Xb2'], g:log)
+  call assert_equal(oldtab, tabpagenr())
+  call assert_equal([0, 0], win_id2tabwin(g:w1))
+  call assert_equal([0, 0], win_id2tabwin(g:w2))
 
   unlet g:tab
-  unlet g:buf
+  unlet g:w1
-  autocmd! test-WinClosed
+  unlet g:w2
-  augroup! test-WinClosed
+  unlet g:log
+  autocmd! test-BufUnload-close-other
+  augroup! test-BufUnload-close-other
   %bwipe!
 endfunc
 
+func Test_BufUnload_close_other()
+  call Run_test_BufUnload_close_other('')
+  call Run_test_BufUnload_close_other('setlocal bufhidden=wipe')
+endfunc
+
 func s:AddAnAutocmd()
   augroup vimBarTest
     au BufReadCmd * echo 'hello'