From 7a114622633909dc0af5daf36e03ae056fcf1bbb Mon Sep 17 00:00:00 2001
From: "kyle.cao" <kyle.cao@vesoft.com>
Date: Thu, 22 Sep 2022 14:14:18 +0800
Subject: [PATCH] fix optional match

---
 src/graph/planner/match/MatchPlanner.cpp      | 27 ++++++++++++++++---
 .../match/MultiLineMultiQueryParts.feature    |  7 +++++
 2 files changed, 31 insertions(+), 3 deletions(-)

diff --git a/src/graph/planner/match/MatchPlanner.cpp b/src/graph/planner/match/MatchPlanner.cpp
index 026c35428ba..4f234b5c891 100644
--- a/src/graph/planner/match/MatchPlanner.cpp
+++ b/src/graph/planner/match/MatchPlanner.cpp
@@ -15,6 +15,7 @@
 #include "graph/planner/plan/Algo.h"
 #include "graph/planner/plan/Logic.h"
 #include "graph/planner/plan/Query.h"
+#include "graph/util/ExpressionUtils.h"
 
 namespace nebula {
 namespace graph {
@@ -76,8 +77,28 @@ Status MatchPlanner::connectMatchPlan(SubPlan& queryPlan, MatchClauseContext* ma
   if (!intersectedAliases.empty()) {
     if (matchCtx->isOptional) {
       // connect LeftJoin match filter
-      if (matchCtx->where != nullptr) {
-        matchCtx->where->inputColNames = matchPlan.root->colNames();
+      auto& whereCtx = matchCtx->where;
+      if (whereCtx.get() != nullptr) {
+        auto exprs =
+            ExpressionUtils::collectAll(whereCtx->filter, {Expression::Kind::kLabelTagProperty});
+
+        // Check if all aliases in where clause are generated by the current match statement pattern
+        std::vector<std::string> aliases;
+        for (const auto* expr : exprs) {
+          DCHECK_EQ(expr->kind(), Expression::Kind::kLabelTagProperty);
+          auto* labelExpr = static_cast<const LabelTagPropertyExpression*>(expr)->label();
+          DCHECK_EQ(labelExpr->kind(), Expression::Kind::kVarProperty);
+          aliases.emplace_back(static_cast<const PropertyExpression*>(labelExpr)->prop());
+        }
+        auto aliasesGenerated = matchCtx->aliasesGenerated;
+        if (!std::all_of(aliases.begin(), aliases.end(), [&aliasesGenerated](std::string& alias) {
+              return aliasesGenerated.find(alias) != aliasesGenerated.end();
+            })) {
+          return Status::SemanticError(
+              "The where clause of optional match statement that reference variables defined by "
+              "other statements is not supported yet.");
+        }
+        whereCtx->inputColNames = matchPlan.root->colNames();
         auto wherePlanStatus =
             std::make_unique<WhereClausePlanner>()->transform(matchCtx->where.get());
         NG_RETURN_IF_ERROR(wherePlanStatus);
@@ -102,7 +123,7 @@ Status MatchPlanner::genQueryPartPlan(QueryContext* qctx,
                                       const QueryPart& queryPart) {
   // generate plan for matchs
   for (auto& match : queryPart.matchs) {
-    connectMatchPlan(queryPlan, match.get());
+    NG_RETURN_IF_ERROR(connectMatchPlan(queryPlan, match.get()));
     // connect match filter
     if (match->where != nullptr && !match->isOptional) {
       match->where->inputColNames = queryPlan.root->colNames();
diff --git a/tests/tck/features/match/MultiLineMultiQueryParts.feature b/tests/tck/features/match/MultiLineMultiQueryParts.feature
index ab0979380e2..05bc40e0429 100644
--- a/tests/tck/features/match/MultiLineMultiQueryParts.feature
+++ b/tests/tck/features/match/MultiLineMultiQueryParts.feature
@@ -354,3 +354,10 @@ Feature: Multi Line Multi Query Parts
       RETURN m
       """
     Then a SemanticError should be raised at runtime: Alias used but not defined: `m'
+    When executing query:
+      """
+      MATCH (m)-[]-(n) WHERE id(m)=="Tim Duncan"
+      OPTIONAL MATCH (n)-->(v) WHERE v.player.age < m.player.age
+      RETURN n,v
+      """
+    Then a SemanticError should be raised at runtime: The where clause of optional match statement that reference variables defined by other statements is not supported yet.