From 1ffd20a26eeb360bc0d2fe8e36120d43134b465a Mon Sep 17 00:00:00 2001
From: Sean Dewar <seandewar@users.noreply.github.com>
Date: Fri, 24 Sep 2021 22:42:31 +0100
Subject: [PATCH] test(unit/eval/typval_spec): don't dereference NULL
 last_msg_hist

If last_msg_hist is NULL, check_emsg will cause the running test process
to SIGSEGV from trying to access the msg member.
---
 test/unit/eval/typval_spec.lua | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/test/unit/eval/typval_spec.lua b/test/unit/eval/typval_spec.lua
index cde5a731cf..5e8677c69d 100644
--- a/test/unit/eval/typval_spec.lua
+++ b/test/unit/eval/typval_spec.lua
@@ -101,12 +101,13 @@ local function check_emsg(f, msg)
     saved_last_msg_hist = nil
   end
   local ret = {f()}
+  local last_msg = lib.last_msg_hist ~= nil and ffi.string(lib.last_msg_hist.msg) or nil
   if msg ~= nil then
-    eq(msg, ffi.string(lib.last_msg_hist.msg))
+    eq(msg, last_msg)
     neq(saved_last_msg_hist, lib.last_msg_hist)
   else
     if saved_last_msg_hist ~= lib.last_msg_hist then
-      eq(nil, ffi.string(lib.last_msg_hist.msg))
+      eq(nil, last_msg)
     else
       eq(saved_last_msg_hist, lib.last_msg_hist)
     end