linda:send() returns nil,<something> in case of error

3 files changed, 16 insertions, 7 deletions

diff --git a/src/lanes.cpp b/src/lanes.cpp
index 9b3b28c..5d40ed4 100644
--- a/src/lanes.cpp
+++ b/src/lanes.cpp
@@ -867,10 +867,10 @@ LANES_API void luaopen_lanes_embedded(lua_State* L_, lua_CFunction _luaopen_lane
 {
     STACK_CHECK_START_REL(L_, 0);
     // pre-require lanes.core so that when lanes.lua calls require "lanes.core" it finds it is already loaded
-    luaL_requiref(L_, "lanes.core", luaopen_lanes_core, 0);                                        // L_: ... lanes.core
+    luaL_requiref(L_, kLanesCoreLibName, luaopen_lanes_core, 0);                                   // L_: ... lanes.core
     lua_pop(L_, 1);                                                                                // L_: ...
     STACK_CHECK(L_, 0);
     // call user-provided function that runs the chunk "lanes.lua" from wherever they stored it
-    luaL_requiref(L_, "lanes", _luaopen_lanes ? _luaopen_lanes : default_luaopen_lanes, 0);        // L_: ... lanes
+    luaL_requiref(L_, kLanesLibName, _luaopen_lanes ? _luaopen_lanes : default_luaopen_lanes, 0);  // L_: ... lanes
     STACK_CHECK(L_, 1);
 }
diff --git a/src/lanes.lua b/src/lanes.lua
index 95c4eff..92e773a 100644
--- a/src/lanes.lua
+++ b/src/lanes.lua
@@ -728,7 +728,8 @@ local genatomic = function(linda_, key_, initial_val_)
     return function(diff_)
         -- 'nil' allows 'key_' to be numeric
         -- suspends until our 'true' is in
-        if linda_:send(nil, key_, true) == cancel_error then
+        local _res, _err = linda_:send(nil, key_, true)
+        if _err == cancel_error then
             return cancel_error
         end
         local val = linda_:get(key_)
diff --git a/src/linda.cpp b/src/linda.cpp
index 4dc2162..1bd5d16 100644
--- a/src/linda.cpp
+++ b/src/linda.cpp
@@ -709,17 +709,25 @@ LUAG_FUNC(linda_send)
 
         switch (_cancel) {
         case CancelRequest::Soft:
-            // if user wants to soft-cancel, the call returns lanes.cancel_error
+            // if user wants to soft-cancel, the call returns nil, kCancelError
+            lua_pushnil(L_);
             kCancelError.pushKey(L_);
-            return 1;
+            return 2;
 
         case CancelRequest::Hard:
             // raise an error interrupting execution only in case of hard cancel
             raise_cancel_error(L_); // raises an error and doesn't return
 
         default:
-            lua_pushboolean(L_, _ret); // true (success) or false (timeout)
-            return 1;
+            if (_ret) {
+                lua_pushboolean(L_, _ret); // true (success)
+                return 1;
+            } else {
+                // not enough room in the Linda slot to fulfill the request, return nil, "timeout"
+                lua_pushnil(L_);
+                std::ignore = luaG_pushstring(L_, "timeout");
+                return 2;
+            }
         }
     };
     return Linda::ProtectedCall(L_, _send);