To: vim-dev@vim.org
Subject: patch 5.4p.5
Fcc: outbox
From: Bram Moolenaar <Bram@moolenaar.net>
------------

Another nasty autocommand problem.  It appears more people are using
autocommands these days.  It requires a radical change to how autocommands are
executed.  But not right now.


Patch 5.4p.5
Problem:    When changing buffers in a BufDelete autocommand, there could be
            ml_line errors and/or a crash. (Schandl)  Was caused by deleting
            the current buffer.
Solution:   When the buffer to be deleted unexpectedly becomes the current
            buffer, don't delete it.
            Also added a check for this in test13.
Files:      src/buffer.c, src/testdir/test13.in, src/testdir/test13.ok


*** ../vim-5.4p/src/buffer.c	Mon Jul 19 11:08:56 1999
--- src/buffer.c	Tue Jul 20 13:17:13 1999
***************
*** 185,190 ****
--- 185,194 ----
      int	    free_buf;
      int	    del_buf;
  {
+ #ifdef AUTOCMD
+     int		is_curbuf;
+ #endif
+ 
      if (buf->b_nwindows > 0)
  	--buf->b_nwindows;
      if (buf->b_nwindows == 0 && win != NULL)
***************
*** 218,226 ****
       * Free all things allocated for this buffer.
       * Also calls the "BufDelete" autocommands when del_buf is TRUE.
       */
      buf_freeall(buf, del_buf);
!     if (!buf_valid(buf))	    /* autocommands may delete the buffer */
  	return;
  
      /*
       * Remove the buffer from the list.
--- 222,242 ----
       * Free all things allocated for this buffer.
       * Also calls the "BufDelete" autocommands when del_buf is TRUE.
       */
+ #ifdef AUTOCMD
+     is_curbuf = (buf == curbuf);
+ #endif
      buf_freeall(buf, del_buf);
! #ifdef AUTOCMD
!     /*
!      * Autocommands may have deleted the buffer.
!      * It's possible that autocommands change curbuf to the one being deleted.
!      * This might cause curbuf to be deleted unexpectedly.  But in some cases
!      * it's OK to delete the curbuf, because a new one is obtained anyway.
!      * Therefore only return if curbuf changed to the deleted buffer.
!      */
!     if (!buf_valid(buf) || (buf == curbuf && !is_curbuf))
  	return;
+ #endif
  
      /*
       * Remove the buffer from the list.
***************
*** 267,276 ****
  /*ARGSUSED*/
      void
  buf_freeall(buf, del_buf)
!     BUF	    *buf;
!     int	    del_buf;	/* buffer is going to be deleted */
  {
  #ifdef AUTOCMD
      apply_autocmds(EVENT_BUFUNLOAD, buf->b_fname, buf->b_fname, FALSE, buf);
      if (!buf_valid(buf))	    /* autocommands may delete the buffer */
  	return;
--- 283,294 ----
  /*ARGSUSED*/
      void
  buf_freeall(buf, del_buf)
!     BUF		*buf;
!     int		del_buf;	/* buffer is going to be deleted */
  {
  #ifdef AUTOCMD
+     int		is_curbuf = (buf == curbuf);
+ 
      apply_autocmds(EVENT_BUFUNLOAD, buf->b_fname, buf->b_fname, FALSE, buf);
      if (!buf_valid(buf))	    /* autocommands may delete the buffer */
  	return;
***************
*** 280,285 ****
--- 298,311 ----
  	if (!buf_valid(buf))	    /* autocommands may delete the buffer */
  	    return;
      }
+     /*
+      * It's possible that autocommands change curbuf to the one being deleted.
+      * This might cause curbuf to be deleted unexpectedly.  But in some cases
+      * it's OK to delete the curbuf, because a new one is obtained anyway.
+      * Therefore only return if curbuf changed to the deleted buffer.
+      */
+     if (buf == curbuf && !is_curbuf)
+ 	return;
  #endif
  #ifdef HAVE_TCL
      tcl_buffer_free(buf);
*** ../vim-5.4p/src/testdir/test13.in	Mon Jul 19 11:08:50 1999
--- src/testdir/test13.in	Tue Jul 20 13:31:27 1999
***************
*** 7,12 ****
--- 7,15 ----
  Also test deleting the buffer on a Unload event.  If this goes wrong there
  will be the ATTENTION prompt.
  
+ Also test changing buffers in a BufDel autocommand.  If this goes wrong there
+ are ml_line errors and/or a Crash.
+ 
  STARTTEST
  :/^start of testfile/,/^end of testfile/w! Xtestje1
  :/^start of testfile/,/^end of testfile/w! Xtestje2
***************
*** 36,41 ****
--- 39,51 ----
  :e Xtestje2
  :sp Xtestje1
  :e
+ :w >>test.out
+ :au!
+ :only
+ :e Xtestje1
+ :bdel Xtestje2 Xtestje3 test.out test13.in
+ :au BufDelete Xtestje1 buf Xtestje1
+ :bd
  :w >>test.out
  :!rm -rf Xtestje*
  :qa!
*** ../vim-5.4p/src/testdir/test13.ok	Mon Jul 19 11:08:50 1999
--- src/testdir/test13.ok	Tue Jul 20 13:35:40 1999
***************
*** 22,24 ****
--- 22,30 ----
  	contents
  	contents
  end of testfile
+ start of testfile
+ testje1
+ 	contents
+ 	contents
+ 	contents
+ end of testfile

--
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--/-/---- Bram Moolenaar ---- Bram@moolenaar.net ---- Bram@vim.org ---\-\--
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