From 0b00aa53f8ca229df0fd32851312bf7f45085978 Mon Sep 17 00:00:00 2001
From: Aiee <18348405+Aiee@users.noreply.github.com>
Date: Fri, 2 Dec 2022 00:28:12 +0800
Subject: [PATCH] Fix edge case

---
 src/graph/planner/match/MatchPathPlanner.cpp  | 39 ++++++++-----------
 .../validator/test/MatchValidatorTest.cpp     |  1 -
 .../features/bugfix/DupAliasInMatch.feature   |  2 +-
 3 files changed, 17 insertions(+), 25 deletions(-)

diff --git a/src/graph/planner/match/MatchPathPlanner.cpp b/src/graph/planner/match/MatchPathPlanner.cpp
index ce13b9eebe6..3c534cb6eb4 100644
--- a/src/graph/planner/match/MatchPathPlanner.cpp
+++ b/src/graph/planner/match/MatchPathPlanner.cpp
@@ -254,10 +254,12 @@ Status MatchPathPlanner::leftExpandFromNode(
   for (size_t i = startIndex; i > 0; --i) {
     auto& node = nodeInfos[i];
     auto& dst = nodeInfos[i - 1];
-    bool expandInto = nodeAliasesSeenInPattern.find(dst.alias) != nodeAliasesSeenInPattern.end();
+
     if (!node.anonymous) {
       nodeAliasesSeenInPattern.emplace(node.alias);
     }
+    bool expandInto = nodeAliasesSeenInPattern.find(dst.alias) != nodeAliasesSeenInPattern.end();
+
     auto& edge = edgeInfos[i - 1];
     auto traverse = Traverse::make(qctx, subplan.root, spaceId);
     traverse->setSrc(nextTraverseStart);
@@ -297,9 +299,10 @@ Status MatchPathPlanner::leftExpandFromNode(
   bool duppedLastAlias =
       nodeAliasesSeenInPattern.find(lastNode.alias) != nodeAliasesSeenInPattern.end() &&
       nodeAliasesSeenInPattern.size() > 1;
-
-  if (!lastNode.anonymous) {
-    nodeAliasesSeenInPattern.emplace(lastNode.alias);
+  // If the the last alias has been presented in the pattern, we could emit the AppendVertices node
+  // because the same alias always presents in the same entity.
+  if (duppedLastAlias) {
+    return Status::OK();
   }
 
   auto appendV = AppendVertices::make(qctx, subplan.root, spaceId);
@@ -313,15 +316,6 @@ Status MatchPathPlanner::leftExpandFromNode(
   appendV->setColNames(genAppendVColNames(subplan.root->colNames(), lastNode, !edgeInfos.empty()));
   subplan.root = appendV;
 
-  if (duppedLastAlias) {
-    auto* startVid = nodeId(qctx->objPool(), lastNode);
-    auto* endVid = nextTraverseStart;
-    auto* filterExpr = RelationalExpression::makeEQ(qctx->objPool(), startVid, endVid);
-    auto* filter = Filter::make(qctx, appendV, filterExpr, false);
-    subplan.root = filter;
-    inputVar = filter->outputVar();
-  }
-
   return Status::OK();
 }
 
@@ -339,10 +333,12 @@ Status MatchPathPlanner::rightExpandFromNode(
   for (size_t i = startIndex; i < edgeInfos.size(); ++i) {
     auto& node = nodeInfos[i];
     auto& dst = nodeInfos[i + 1];
-    bool expandInto = nodeAliasesSeenInPattern.find(dst.alias) != nodeAliasesSeenInPattern.end();
+
     if (!node.anonymous) {
       nodeAliasesSeenInPattern.emplace(node.alias);
     }
+    bool expandInto = nodeAliasesSeenInPattern.find(dst.alias) != nodeAliasesSeenInPattern.end();
+
     auto& edge = edgeInfos[i];
     auto traverse = Traverse::make(qctx, subplan.root, spaceId);
     traverse->setSrc(nextTraverseStart);
@@ -380,6 +376,12 @@ Status MatchPathPlanner::rightExpandFromNode(
     nodeAliasesSeenInPattern.emplace(lastNode.alias);
   }
 
+  // If the the last alias has been presented in the pattern, we could emit the AppendVertices node
+  // because the same alias always presents in the same entity.
+  if (duppedLastAlias) {
+    return Status::OK();
+  }
+
   auto appendV = AppendVertices::make(qctx, subplan.root, spaceId);
   auto vertexProps = SchemaUtil::getAllVertexProp(qctx, spaceId, true);
   NG_RETURN_IF_ERROR(vertexProps);
@@ -391,15 +393,6 @@ Status MatchPathPlanner::rightExpandFromNode(
   appendV->setColNames(genAppendVColNames(subplan.root->colNames(), lastNode, !edgeInfos.empty()));
   subplan.root = appendV;
 
-  if (duppedLastAlias) {
-    auto* startVid = nodeId(qctx->objPool(), lastNode);
-    auto* endVid = nextTraverseStart;
-    auto* filterExpr = RelationalExpression::makeEQ(qctx->objPool(), startVid, endVid);
-    auto* filter = Filter::make(qctx, appendV, filterExpr, false);
-    subplan.root = filter;
-    inputVar = filter->outputVar();
-  }
-
   return Status::OK();
 }
 
diff --git a/src/graph/validator/test/MatchValidatorTest.cpp b/src/graph/validator/test/MatchValidatorTest.cpp
index f80acede978..694fc4701d4 100644
--- a/src/graph/validator/test/MatchValidatorTest.cpp
+++ b/src/graph/validator/test/MatchValidatorTest.cpp
@@ -541,7 +541,6 @@ TEST_F(MatchValidatorTest, validateAlias) {
     std::vector<PlanNode::Kind> expected = {PlanNode::Kind::kProject,
                                             PlanNode::Kind::kProject,
                                             PlanNode::Kind::kFilter,
-                                            PlanNode::Kind::kAppendVertices,
                                             PlanNode::Kind::kTraverse,
                                             PlanNode::Kind::kTraverse,
                                             PlanNode::Kind::kIndexScan,
diff --git a/tests/tck/features/bugfix/DupAliasInMatch.feature b/tests/tck/features/bugfix/DupAliasInMatch.feature
index b6e065dd072..ac5b4ed19b2 100644
--- a/tests/tck/features/bugfix/DupAliasInMatch.feature
+++ b/tests/tck/features/bugfix/DupAliasInMatch.feature
@@ -36,7 +36,7 @@ Feature: Duplicate alias in MATCH
       | n1 |
 
   Scenario: Duplicate node alias expand both direction
-    # expand from left to right
+    # expand from middle to both sides
     When executing query:
       """
       MATCH (n1)-[]->(n0)-[]->(n1)-[]->(n1)-[]->(n1) WHERE (id(n0) == "Tim Duncan") RETURN n1