jp_issue_933.patch

diff --git a/src/buffer.c b/src/buffer.c
index 75de736..db632fa 100644
--- a/src/buffer.c
+++ b/src/buffer.c
@@ -499,6 +499,10 @@ close_buffer(
     /* When the buffer is no longer in a window, trigger BufWinLeave */
     if (buf->b_nwindows == 1)
     {
+# ifdef FEAT_WINDOWS
+	tabpage_T  *save_curtab = curtab;
+# endif
+
 	buf->b_closing = TRUE;
 	if (apply_autocmds(EVENT_BUFWINLEAVE, buf->b_fname, buf->b_fname,
 								  FALSE, buf)
@@ -533,6 +537,10 @@ aucmd_abort:
 	if (aborting())	    /* autocmds may abort script processing */
 	    return;
 # endif
+# ifdef FEAT_WINDOWS
+	if (save_curtab != curtab)
+	    return;
+# endif
     }
     nwindows = buf->b_nwindows;
 #endif
@@ -561,7 +569,9 @@ aucmd_abort:
     buf->b_nwindows = nwindows;
 #endif
 
-    buf_freeall(buf, (del_buf ? BFA_DEL : 0) + (wipe_buf ? BFA_WIPE : 0));
+    if (buf_freeall(buf, (del_buf ? BFA_DEL : 0) + (wipe_buf ? BFA_WIPE : 0))
+									== FAIL)
+	return;
 
 #ifdef FEAT_AUTOCMD
     /* Autocommands may have deleted the buffer. */
@@ -670,13 +680,17 @@ buf_clear_file(buf_T *buf)
  * BFA_DEL	  buffer is going to be deleted
  * BFA_WIPE	  buffer is going to be wiped out
  * BFA_KEEP_UNDO  do not free undo information
+ * Return FAIL for failure, OK otherwise.
  */
-    void
+    int
 buf_freeall(buf_T *buf, int flags)
 {
 #ifdef FEAT_AUTOCMD
     int		is_curbuf = (buf == curbuf);
     bufref_T	bufref;
+# ifdef FEAT_WINDOWS
+    tabpage_T	*save_curtab = curtab;
+# endif
 
     buf->b_closing = TRUE;
     set_bufref(&bufref, buf);
@@ -686,7 +700,7 @@ buf_freeall(buf_T *buf, int flags)
 								  FALSE, buf)
 		&& !bufref_valid(&bufref))
 	    /* autocommands deleted the buffer */
-	    return;
+	    return FAIL;
     }
     if ((flags & BFA_DEL) && buf->b_p_bl)
     {
@@ -694,7 +708,7 @@ buf_freeall(buf_T *buf, int flags)
 								   FALSE, buf)
 		&& !bufref_valid(&bufref))
 	    /* autocommands deleted the buffer */
-	    return;
+	    return FAIL;
     }
     if (flags & BFA_WIPE)
     {
@@ -702,12 +716,16 @@ buf_freeall(buf_T *buf, int flags)
 								  FALSE, buf)
 		&& !bufref_valid(&bufref))
 	    /* autocommands deleted the buffer */
-	    return;
+	    return FAIL;
     }
     buf->b_closing = FALSE;
 # ifdef FEAT_EVAL
     if (aborting())	    /* autocmds may abort script processing */
-	return;
+	return FAIL;
+# endif
+# ifdef FEAT_WINDOWS
+    if (save_curtab != curtab)
+	return FAIL;
 # endif
 
     /*
@@ -717,7 +735,7 @@ buf_freeall(buf_T *buf, int flags)
      * Therefore only return if curbuf changed to the deleted buffer.
      */
     if (buf == curbuf && !is_curbuf)
-	return;
+	return FAIL;
 #endif
 #ifdef FEAT_DIFF
     diff_buf_delete(buf);	    /* Can't use 'diff' for unloaded buffer. */
@@ -759,6 +777,7 @@ buf_freeall(buf_T *buf, int flags)
     syntax_clear(&buf->b_s);	    /* reset syntax info */
 #endif
     buf->b_flags &= ~BF_READERR;    /* a read error is no longer relevant */
+    return OK;
 }
 
 /*
@@ -1940,7 +1959,8 @@ buflist_new(
     if (buf == curbuf)
     {
 	/* free all things allocated for this buffer */
-	buf_freeall(buf, 0);
+	if (buf_freeall(buf, 0) == FAIL)
+	    return NULL;
 	if (buf != curbuf)	 /* autocommands deleted the buffer! */
 	    return NULL;
 #if defined(FEAT_AUTOCMD) && defined(FEAT_EVAL)
diff --git a/src/ex_cmds.c b/src/ex_cmds.c
index 9e6a72d..57ff429 100644
--- a/src/ex_cmds.c
+++ b/src/ex_cmds.c
@@ -4098,7 +4098,13 @@ do_ecmd(
 		goto theend;
 	    }
 	    u_unchanged(curbuf);
-	    buf_freeall(curbuf, BFA_KEEP_UNDO);
+	    if (buf_freeall(curbuf, BFA_KEEP_UNDO) == FAIL)
+	    {
+#ifdef FEAT_AUTOCMD
+		vim_free(new_name);
+#endif
+		goto theend;
+	    }
 
 	    /* tell readfile() not to clear or reload undo info */
 	    readfile_flags = READ_KEEP_UNDO;
@@ -4394,6 +4400,11 @@ delbuf_msg(char_u *name)
     vim_free(name);
     au_new_curbuf.br_buf = NULL;
     au_new_curbuf.br_buf_free_count = 0;
+
+# ifdef FEAT_WINDOWS
+    if (curwin->w_buffer == NULL)
+	enter_buffer(curbuf);
+# endif
 }
 #endif
 
diff --git a/src/proto/buffer.pro b/src/proto/buffer.pro
index 183f79a..dbe152b 100644
--- a/src/proto/buffer.pro
+++ b/src/proto/buffer.pro
@@ -5,7 +5,7 @@ int bufref_valid(bufref_T *bufref);
 int buf_valid(buf_T *buf);
 void close_buffer(win_T *win, buf_T *buf, int action, int abort_if_last);
 void buf_clear_file(buf_T *buf);
-void buf_freeall(buf_T *buf, int flags);
+int buf_freeall(buf_T *buf, int flags);
 void goto_buffer(exarg_T *eap, int start, int dir, int count);
 void handle_swap_exists(bufref_T *old_curbuf);
 char_u *do_bufdel(int command, char_u *arg, int addr_count, int start_bnr, int end_bnr, int forceit);
diff --git a/src/testdir/test_autocmd.vim b/src/testdir/test_autocmd.vim
index d856d32..7afa261 100644
--- a/src/testdir/test_autocmd.vim
+++ b/src/testdir/test_autocmd.vim
@@ -77,11 +77,48 @@ function Test_autocmd_bufunload_with_tabnext()
   quit
   call assert_equal(2, tabpagenr('$'))
 
+  autocmd! test_autocmd_bufunload_with_tabnext_group
   augroup! test_autocmd_bufunload_with_tabnext_group
   tablast
   quit
 endfunc
 
+" SEGV occurs in older version.  (At least 7.4.2247 or older)
+function Test_autocmd_bufunload_avoiding_SEGV_01()
+  edit a.txt
+
+  augroup test_autocmd_bufunload
+    autocmd!
+    autocmd BufUnload <buffer> tabfirst | 2bwipeout!
+  augroup END
+
+  edit b.txt
+  call assert_equal(3, bufnr('$'))
+
+  autocmd! test_autocmd_bufunload
+  augroup! test_autocmd_bufunload
+  only!
+endfunc
+
+" SEGV occurs in older version.  (At least 7.4.2247 or older)
+function Test_autocmd_bufunload_avoiding_SEGV_02()
+  setlocal buftype=nowrite
+
+  augroup test_autocmd_bufunload
+    autocmd!
+    autocmd BufUnload <buffer> tabfirst | 2bwipeout
+  augroup END
+
+  normal! i1
+  edit a.txt
+  call feedkeys("\<CR>", 'tx')
+  call assert_equal(1, bufnr('$'))
+
+  autocmd! test_autocmd_bufunload
+  augroup! test_autocmd_bufunload
+  new | only!
+endfunc
+
 func Test_win_tab_autocmd()
   let g:record = []
 
@@ -168,3 +205,5 @@ func Test_augroup_warning()
   augroup END
   call assert_true(match(execute('au VimEnter'), "-Deleted-.*VimEnter") >= 0)
 endfunc
+
+" vim: shiftwidth=2 sts=2 expandtab
diff --git a/src/window.c b/src/window.c
index b015d1d..71202b8 100644
--- a/src/window.c
+++ b/src/window.c
@@ -2305,7 +2305,12 @@ win_close(win_T *win, int free_buf)
      * and then close the window and the tab page to avoid that curwin and
      * curtab are invalid while we are freeing memory. */
     if (close_last_window_tabpage(win, free_buf, prev_curtab))
-      return FAIL;
+    {
+	/* Autocommands have close curwin's buf.  Restore curwin->w_buffer */
+	if (win_valid(curwin) && curwin->w_buffer == NULL)
+	    curwin->w_buffer = curbuf;
+	return FAIL;
+    }
 
     /* When closing the help window, try restoring a snapshot after closing
      * the window.  Otherwise clear the snapshot, it's now invalid. */