From 20a4ec756cb8e8f77bc0faf98951f0825e3b5595 Mon Sep 17 00:00:00 2001
From: Aiee <18348405+Aiee@users.noreply.github.com>
Date: Mon, 28 Nov 2022 11:22:21 +0800
Subject: [PATCH] Fix dup alias in MATCH

---
 src/graph/planner/match/MatchPathPlanner.cpp  | 22 +++++++++
 .../features/bugfix/DupAliasInMatch.feature   | 45 +++++++++++++++++++
 2 files changed, 67 insertions(+)
 create mode 100644 tests/tck/features/bugfix/DupAliasInMatch.feature

diff --git a/src/graph/planner/match/MatchPathPlanner.cpp b/src/graph/planner/match/MatchPathPlanner.cpp
index 152be863342..f5e5c96cf45 100644
--- a/src/graph/planner/match/MatchPathPlanner.cpp
+++ b/src/graph/planner/match/MatchPathPlanner.cpp
@@ -308,6 +308,17 @@ Status MatchPathPlanner::leftExpandFromNode(
   appendV->setColNames(genAppendVColNames(subplan.root->colNames(), node, !edgeInfos.empty()));
   subplan.root = appendV;
 
+  auto& lastNode = nodeInfos.front();
+  bool expandInto = nodeAliasesSeenInPattern.find(lastNode.alias) != nodeAliasesSeenInPattern.end();
+  if (expandInto) {
+    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();
 }
 
@@ -371,6 +382,17 @@ Status MatchPathPlanner::rightExpandFromNode(
   appendV->setColNames(genAppendVColNames(subplan.root->colNames(), node, !edgeInfos.empty()));
   subplan.root = appendV;
 
+  auto& lastNode = nodeInfos.back();
+  bool expandInto = nodeAliasesSeenInPattern.find(lastNode.alias) != nodeAliasesSeenInPattern.end();
+  if (expandInto) {
+    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/tests/tck/features/bugfix/DupAliasInMatch.feature b/tests/tck/features/bugfix/DupAliasInMatch.feature
new file mode 100644
index 00000000000..b6e065dd072
--- /dev/null
+++ b/tests/tck/features/bugfix/DupAliasInMatch.feature
@@ -0,0 +1,45 @@
+# Copyright (c) 2022 vesoft inc. All rights reserved.
+#
+# This source code is licensed under Apache 2.0 License.
+# Issue link: https://github.com/vesoft-inc/nebula-ent/issues/1605
+Feature: Duplicate alias in MATCH
+
+  Background:
+    Given a graph with space named "nba"
+
+  Scenario: Duplicate node alias
+    # expand from left to right
+    When executing query:
+      """
+      MATCH (n0)-[]->(n1)-[]->(n1) WHERE (id(n0) == "Tim Duncan") RETURN n1
+      """
+    Then the result should be, in any order:
+      | n1 |
+    # expand from right to left
+    When executing query:
+      """
+      MATCH (n1)<-[]-(n1)<-[]-(n0) WHERE (id(n0) == "Tim Duncan") RETURN n1
+      """
+    Then the result should be, in any order:
+      | n1 |
+    When executing query:
+      """
+      MATCH (n0)-[]->(n1)-[]->(n1)-[]->(n1) WHERE (id(n0) == "Tim Duncan") RETURN n1
+      """
+    Then the result should be, in any order:
+      | n1 |
+    When executing query:
+      """
+      MATCH (n0)-[]->(n1)-[]->(n1)-[]->(n1)-[]->(n1) WHERE (id(n0) == "Tim Duncan") RETURN n1
+      """
+    Then the result should be, in any order:
+      | n1 |
+
+  Scenario: Duplicate node alias expand both direction
+    # expand from left to right
+    When executing query:
+      """
+      MATCH (n1)-[]->(n0)-[]->(n1)-[]->(n1)-[]->(n1) WHERE (id(n0) == "Tim Duncan") RETURN n1
+      """
+    Then the result should be, in any order:
+      | n1 |