Merge #5729 from jamessan/vim-7.4.1751

vim-patch:7.4.1751,8d8aa0a

src/nvim/tag.c

@@ -214,8 +214,12 @@ do_tag (
    * Don't add a tag to the tagstack if 'tagstack' has been reset.
    */
   if (!p_tgst && *tag != NUL) {
-    use_tagstack = FALSE;
-    new_tag = TRUE;
+    use_tagstack = false;
+    new_tag = true;
+    if (g_do_tagpreview != 0) {
+      xfree(ptag_entry.tagname);
+      ptag_entry.tagname = vim_strsave(tag);
+    }
   } else {
     if (g_do_tagpreview != 0)
       use_tagstack = FALSE;

src/nvim/testdir/test_alot.vim

@@ -18,5 +18,6 @@ source test_statusline.vim
 source test_syn_attr.vim
 source test_tabline.vim
 source test_tabpage.vim
+source test_tagjump.vim
 source test_unlet.vim
 source test_matchadd_conceal_utf8.vim

src/nvim/testdir/test_tagjump.vim

@@ -0,0 +1,9 @@
+" Tests for tagjump (tags and special searches)
+
+" SEGV occurs in older versions.  (At least 7.4.1748 or older)
+func Test_ptag_with_notagstack()
+  set notagstack
+  call assert_fails('ptag does_not_exist_tag_name', 'E426')
+  set tagstack&vim
+endfunc
+" vim: sw=2 et

src/nvim/version.c

@@ -693,7 +693,7 @@ static int included_patches[] = {
   1753,
   // 1753,
   // 1752,
-  // 1751,
+  1751,
   // 1750 NA
   // 1749 NA
   1748,