patch 7.4.2312
Problem:    Crash when autocommand moves to another tab. (Dominique Pelle)
Solution:   When navigating to another window halfway the :edit command go
            back to the right window.
diff --git a/src/buffer.c b/src/buffer.c
index 4841f9a..9270c39 100644
--- a/src/buffer.c
+++ b/src/buffer.c
@@ -666,7 +666,8 @@
 
 /*
  * buf_freeall() - free all things allocated for a buffer that are related to
- * the file.  flags:
+ * the file.  Careful: get here with "curwin" NULL when exiting.
+ * flags:
  * 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
@@ -677,7 +678,13 @@
 #ifdef FEAT_AUTOCMD
     int		is_curbuf = (buf == curbuf);
     bufref_T	bufref;
+# ifdef FEAT_WINDOWS
+    int		is_curwin = (curwin!= NULL && curwin->w_buffer == buf);
+    win_T	*the_curwin = curwin;
+    tabpage_T	*the_curtab = curtab;
+# endif
 
+    /* Make sure the buffer isn't closed by autocommands. */
     buf->b_closing = TRUE;
     set_bufref(&bufref, buf);
     if (buf->b_ml.ml_mfp != NULL)
@@ -705,6 +712,19 @@
 	    return;
     }
     buf->b_closing = FALSE;
+
+# ifdef FEAT_WINDOWS
+    /* 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();
+    }
+# endif
+
 # ifdef FEAT_EVAL
     if (aborting())	    /* autocmds may abort script processing */
 	return;
diff --git a/src/ex_cmds.c b/src/ex_cmds.c
index 1deb8a3..61ab2ab 100644
--- a/src/ex_cmds.c
+++ b/src/ex_cmds.c
@@ -3935,25 +3935,28 @@
 		auto_buf = TRUE;
 	    else
 	    {
+		win_T	    *the_curwin = curwin;
+
+		/* Set the w_closing flag to avoid that autocommands close the
+		 * window. */
+		the_curwin->w_closing = TRUE;
+
 		if (curbuf == old_curbuf.br_buf)
 #endif
 		    buf_copy_options(buf, BCO_ENTER);
 
-		/* close the link to the current buffer */
+		/* Close the link to the current buffer. This will set
+		 * curwin->w_buffer to NULL. */
 		u_sync(FALSE);
 		close_buffer(oldwin, curbuf,
 			       (flags & ECMD_HIDE) ? 0 : DOBUF_UNLOAD, FALSE);
 
 #ifdef FEAT_AUTOCMD
-		/* Autocommands may open a new window and leave oldwin open
-		 * which leads to crashes since the above call sets
-		 * oldwin->w_buffer to NULL. */
-		if (curwin != oldwin && oldwin != aucmd_win
-			     && win_valid(oldwin) && oldwin->w_buffer == NULL)
-		    win_close(oldwin, FALSE);
+		the_curwin->w_closing = FALSE;
 
 # ifdef FEAT_EVAL
-		if (aborting())	    /* autocmds may abort script processing */
+		/* autocmds may abort script processing */
+		if (aborting() && curwin->w_buffer != NULL)
 		{
 		    vim_free(new_name);
 		    goto theend;
diff --git a/src/ex_docmd.c b/src/ex_docmd.c
index 866b347..b568e46 100644
--- a/src/ex_docmd.c
+++ b/src/ex_docmd.c
@@ -2475,12 +2475,7 @@
 		&& !IS_USER_CMDIDX(ea.cmdidx))
 	{
 	    /* Command not allowed when editing the command line. */
-#ifdef FEAT_CMDWIN
-	    if (cmdwin_type != 0)
-		errormsg = (char_u *)_(e_cmdwin);
-	    else
-#endif
-		errormsg = (char_u *)_(e_secure);
+	    errormsg = get_text_locked_msg();
 	    goto doend;
 	}
 #ifdef FEAT_AUTOCMD
diff --git a/src/ex_getln.c b/src/ex_getln.c
index 110a95a..1627ee7 100644
--- a/src/ex_getln.c
+++ b/src/ex_getln.c
@@ -2133,12 +2133,17 @@
     void
 text_locked_msg(void)
 {
+    EMSG(_(get_text_locked_msg()));
+}
+
+    char_u *
+get_text_locked_msg(void)
+{
 #ifdef FEAT_CMDWIN
     if (cmdwin_type != 0)
-	EMSG(_(e_cmdwin));
-    else
+	return e_cmdwin;
 #endif
-	EMSG(_(e_secure));
+    return e_secure;
 }
 
 #if defined(FEAT_AUTOCMD) || defined(PROTO)
diff --git a/src/proto/ex_getln.pro b/src/proto/ex_getln.pro
index 581bfce..afc875c 100644
--- a/src/proto/ex_getln.pro
+++ b/src/proto/ex_getln.pro
@@ -3,6 +3,7 @@
 char_u *getcmdline_prompt(int firstc, char_u *prompt, int attr, int xp_context, char_u *xp_arg);
 int text_locked(void);
 void text_locked_msg(void);
+char_u *get_text_locked_msg(void);
 int curbuf_locked(void);
 int allbuf_locked(void);
 char_u *getexline(int c, void *cookie, int indent);
diff --git a/src/testdir/test_tabpage.vim b/src/testdir/test_tabpage.vim
index 7bdea0b..0bf7d05 100644
--- a/src/testdir/test_tabpage.vim
+++ b/src/testdir/test_tabpage.vim
@@ -218,7 +218,7 @@
   bw!
 endfunction
 
-func Test_tabnext_on_buf_unload()
+func Test_tabnext_on_buf_unload1()
   " This once caused a crash
   new
   tabedit
@@ -227,7 +227,19 @@
   q
 
   while tabpagenr('$') > 1
-    quit
+    bwipe!
+  endwhile
+endfunc
+
+func Test_tabnext_on_buf_unload2()
+  " This once caused a crash
+  tabedit
+  autocmd BufUnload <buffer> tabnext
+  file x
+  edit y
+
+  while tabpagenr('$') > 1
+    bwipe!
   endwhile
 endfunc
 
diff --git a/src/version.c b/src/version.c
index ff7f236..df1de63 100644
--- a/src/version.c
+++ b/src/version.c
@@ -764,6 +764,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    2312,
+/**/
     2311,
 /**/
     2310,
diff --git a/src/window.c b/src/window.c
index 2f3ec8c..4f99271 100644
--- a/src/window.c
+++ b/src/window.c
@@ -3912,12 +3912,7 @@
     if (text_locked())
     {
 	/* Not allowed when editing the command line. */
-#ifdef FEAT_CMDWIN
-	if (cmdwin_type != 0)
-	    EMSG(_(e_cmdwin));
-	else
-#endif
-	    EMSG(_(e_secure));
+	text_locked_msg();
 	return;
     }