patch 7.4.2309

Problem:    Crash when doing tabnext in a BufUnload autocmd. (Dominique Pelle)
Solution:   When detecting that the tab page changed, don't just abort but
            delete the window where w_buffer is NULL.

src/testdir/test_tabpage.vim

@@ -218,4 +218,18 @@ function Test_tabpage_with_tab_modifier()
   bw!
 endfunction
 
+func Test_tabnext_on_buf_unload()
+  " This once caused a crash
+  new
+  tabedit
+  tabfirst
+  au BufUnload <buffer> tabnext
+  q
+
+  while tabpagenr('$') > 1
+    quit
+  endwhile
+endfunc
+
+
 " vim: shiftwidth=2 sts=2 expandtab

src/version.c

@@ -763,6 +763,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    2309,
 /**/
     2308,
 /**/

src/window.c

@@ -2379,7 +2379,7 @@ win_close(win_T *win, int free_buf)
 #endif
 	close_buffer(win, win->w_buffer, free_buf ? DOBUF_UNLOAD : 0, TRUE);
 #ifdef FEAT_AUTOCMD
-	if (win_valid(win))
+	if (win_valid_any_tab(win))
 	    win->w_closing = FALSE;
 #endif
 	/* Make sure curbuf is valid. It can become invalid if 'bufhidden' is
@@ -2399,9 +2399,18 @@ win_close(win_T *win, int free_buf)
 	getout(0);
     }
 
-    /* Autocommands may have closed the window already, or closed the only
+    /* Autocommands may have moved to another tab page. */
-     * other window or moved to another tab page. */
+    if (curtab != prev_curtab && win_valid_any_tab(win)
-    else if (!win_valid(win) || last_window() || curtab != prev_curtab
+						      && win->w_buffer == NULL)
+    {
+	/* Need to close the window anyway, since the buffer is NULL. */
+	win_close_othertab(win, FALSE, prev_curtab);
+	return FAIL;
+    }
+
+    /* Autocommands may have closed the window already or closed the only
+     * other window. */
+    if (!win_valid(win) || last_window()
 	    || close_last_window_tabpage(win, free_buf, prev_curtab))
 	return FAIL;
 
@@ -2492,10 +2501,13 @@ win_close_othertab(win_T *win, int free_buf, tabpage_T *tp)
     int		free_tp = FALSE;
 
 #ifdef FEAT_AUTOCMD
-    if (win->w_closing || win->w_buffer->b_closing)
+    /* Get here with win->w_buffer == NULL when win_close() detects the tab
+     * page changed. */
+    if (win->w_closing || (win->w_buffer != NULL && win->w_buffer->b_closing))
 	return; /* window is already being closed */
 #endif
 
+    if (win->w_buffer != NULL)
 	/* Close the link to the buffer. */
 	close_buffer(win, win->w_buffer, free_buf ? DOBUF_UNLOAD : 0, FALSE);