From fdcaa0a9d9831a852c784b93b6a12746e0a7c591 Mon Sep 17 00:00:00 2001
From: shylock <33566796+Shylock-Hg@users.noreply.github.com>
Date: Mon, 21 Feb 2022 17:55:19 +0800
Subject: [PATCH] Fix crash of null path expression. (#3915)

* Fix crash of null path expression.

* Add test case.

Co-authored-by: jakevin <30525741+jackwener@users.noreply.github.com>
---
 src/graph/planner/match/MatchClausePlanner.cpp  |  2 +-
 .../bugfix/CrashWhenNullPathExpr.feature        | 17 +++++++++++++++++
 2 files changed, 18 insertions(+), 1 deletion(-)
 create mode 100644 tests/tck/features/bugfix/CrashWhenNullPathExpr.feature

diff --git a/src/graph/planner/match/MatchClausePlanner.cpp b/src/graph/planner/match/MatchClausePlanner.cpp
index 3bbc1985593..ed998b79512 100644
--- a/src/graph/planner/match/MatchClausePlanner.cpp
+++ b/src/graph/planner/match/MatchClausePlanner.cpp
@@ -409,7 +409,7 @@ Status MatchClausePlanner::projectColumnsBySymbols(MatchClauseContext* matchClau
     auto iter = std::find_if(aliases.begin(), aliases.end(), [](const auto& alias) {
       return alias.second == AliasType::kPath;
     });
-    if (iter != aliases.end()) {
+    if (iter != aliases.end() && path.pathBuild != nullptr) {
       auto& alias = iter->first;
       columns->addColumn(buildPathColumn(path.pathBuild, alias));
       colNames.emplace_back(alias);
diff --git a/tests/tck/features/bugfix/CrashWhenNullPathExpr.feature b/tests/tck/features/bugfix/CrashWhenNullPathExpr.feature
new file mode 100644
index 00000000000..ed5392bf9e3
--- /dev/null
+++ b/tests/tck/features/bugfix/CrashWhenNullPathExpr.feature
@@ -0,0 +1,17 @@
+# Copyright (c) 2022 vesoft inc. All rights reserved.
+#
+# This source code is licensed under Apache 2.0 License.
+Feature: Test crash when null path expression
+
+  Background:
+    Given a graph with space named "nba"
+
+  Scenario: Null path expression in multiple patterns
+    When executing query:
+      """
+      MATCH (p:player {name: 'Yao Ming'} ), (t:team {name: 'Rockets'}), pth = (p)-[:serve*1..4]-(t)
+      RETURN pth
+      """
+    Then the result should be, in any order, with relax comparison:
+      | pth                                                                                                                       |
+      | <("Yao Ming":player{age:38,name:"Yao Ming"})-[:serve@0{end_year:2011,start_year:2002}]->("Rockets":team{name:"Rockets"})> |