Add error messages to lua_h_exists

Previously, if LUA_INCDIR was specified but invalid, install and other
commands would error without a message, eventually causing a failed
assertion in cmd.lua and leaving a hard-to-troubleshoot situation
with no information.

1 files changed, 4 insertions, 0 deletions

diff --git a/src/luarocks/deps.lua b/src/luarocks/deps.lua
index 2233f74a..f6de0db8 100644
--- a/src/luarocks/deps.lua
+++ b/src/luarocks/deps.lua
@@ -665,7 +665,11 @@ local function lua_h_exists(d, luaver)
       if data:match("LUA_VERSION_NUM%s*" .. tostring(luanum)) then
          return d
       end
+
+      return nil, "Lua header mismatches configured version. You may need to install them or configure LUA_INCDIR.", "dependency"
    end
+
+   return nil, "Failed finding Lua header files. You may need to install them or configure LUA_INCDIR.", "dependency"
 end
 
 local function find_lua_incdir(prefix, luaver, luajitver)