Fix single thread ring channel (#882)

.github/workflows/ci.yml

@@ -166,10 +166,10 @@ jobs:
           RUST_LOG=debug ./zenoh-standalone/zenohd &
           echo "zenohd-pid=$!" >> $GITHUB_OUTPUT
 
-      - name: Build project and run test
+      - name: Build project and run tests
         run: |
           sudo apt install -y ninja-build
-          CMAKE_GENERATOR=Ninja make
+          CMAKE_GENERATOR=Ninja ASAN=ON make test
           python3 ./build/tests/single_thread.py
         timeout-minutes: 5
         env:

src/collections/ring_mt.c

@@ -107,14 +107,17 @@ z_result_t _z_ring_mt_pull(void *dst, void *context, z_element_move_f element_mo
         }
     }
     _Z_RETURN_IF_ERR(_z_mutex_unlock(&r->_mutex))
-    if (r->is_closed && src == NULL) return _Z_RES_CHANNEL_CLOSED;
-    element_move(dst, src);
 #else   // Z_FEATURE_MULTI_THREAD == 1
     void *src = _z_ring_pull(&r->_ring);
+#endif  // Z_FEATURE_MULTI_THREAD == 1
+
+    if (r->is_closed && src == NULL) {
+        return _Z_RES_CHANNEL_CLOSED;
+    }
+
     if (src != NULL) {
         element_move(dst, src);
     }
-#endif  // Z_FEATURE_MULTI_THREAD == 1
 
     return _Z_RES_OK;
 }

tests/z_channels_test.c

@@ -190,14 +190,14 @@ void zero_size_test(void) {
     z_owned_fifo_handler_sample_t fifo_handler;
     assert(z_fifo_channel_sample_new(&closure, &fifo_handler, 0) != Z_OK);
     assert(z_fifo_channel_sample_new(&closure, &fifo_handler, 1) == Z_OK);
-    z_drop(z_move(fifo_handler));
     z_drop(z_move(closure));
+    z_drop(z_move(fifo_handler));
 
     z_owned_ring_handler_sample_t ring_handler;
     assert(z_ring_channel_sample_new(&closure, &ring_handler, 0) != Z_OK);
     assert(z_ring_channel_sample_new(&closure, &ring_handler, 1) == Z_OK);
-    z_drop(z_move(ring_handler));
     z_drop(z_move(closure));
+    z_drop(z_move(ring_handler));
 }
 
 int main(void) {