add: recover debug function

Author: peace-dove

src/cypher/execution_plan/ops/op_var_len_expand.h

@@ -21,6 +21,17 @@
 #include "cypher/execution_plan/ops/op.h"
 #include "filter/filter.h"
 
+#ifndef NDEBUG
+#define VAR_LEN_EXP_DUMP_FOR_DEBUG()                                                         \
+    do {                                                                                       \
+        LOG_DEBUG() << __func__ << __LINE__ << ": hop=" << hop_ << ", edge="                   \
+                  << (hop_ == 0 ? "na" : _detail::EdgeUid2String(eits_[hop_ - 1].GetUid())); \
+        LOG_DEBUG() << pattern_graph_->VisitedEdges().Dump();                                  \
+    } while (0)
+#else
+#define VAR_LEN_EXP_DUMP_FOR_DEBUG()
+#endif
+
 namespace cypher {
 
 struct DfsState {