Fix neovim tag bugs uncovered by vim-8.2.0088,

but not related to the patch.  Specifically:

    - settagstack()'s e_listreq is in the wrong place
    - in :ltag, vim_strncpy -> xstrlcpy length parameter is different
        xstrlcpy's length includes the null terminator (so add one)
    - in :ltag, STRNCAT -> xstrlcat takes dest size, not number to copy
        use snprintf instead

2 files changed, 4 insertions, 4 deletions

diff --git a/src/nvim/eval/funcs.c b/src/nvim/eval/funcs.c
index 9edf5c8f7e..5f08b53e50 100644
--- a/src/nvim/eval/funcs.c
+++ b/src/nvim/eval/funcs.c
@@ -8809,8 +8809,6 @@ static void f_settagstack(typval_T *argvars, typval_T *rettv, FunPtr fptr)
 
     if (set_tagstack(wp, d, action) == OK) {
       rettv->vval.v_number = 0;
-    } else {
-      EMSG(_(e_listreq));
     }
 }
 
diff --git a/src/nvim/tag.c b/src/nvim/tag.c
index aa0e93a0d5..f7a55e7a55 100644
--- a/src/nvim/tag.c
+++ b/src/nvim/tag.c
@@ -908,7 +908,7 @@ add_llist_tags(
         if (len > 128) {
             len = 128;
         }
-        xstrlcpy((char *)tag_name, (const char *)tagp.tagname, len);
+        xstrlcpy((char *)tag_name, (const char *)tagp.tagname, len + 1);
         tag_name[len] = NUL;
 
         // Save the tag file name
@@ -975,7 +975,8 @@ add_llist_tags(
             if (cmd_len > (CMDBUFFSIZE - 5)) {
                 cmd_len = CMDBUFFSIZE - 5;
             }
-            xstrlcat((char *)cmd, (char *)cmd_start, cmd_len);
+            snprintf((char *)cmd + len, CMDBUFFSIZE + 1 - len,
+                     "%.*s", cmd_len, cmd_start);
             len += cmd_len;
 
             if (cmd[len - 1] == '$') {
@@ -3406,6 +3407,7 @@ int set_tagstack(win_T *wp, const dict_T *d, int action)
 
   if ((di = tv_dict_find(d, "items", -1)) != NULL) {
     if (di->di_tv.v_type != VAR_LIST) {
+      EMSG(_(e_listreq));
       return FAIL;
     }
     l = di->di_tv.vval.v_list;