Return a plain null value instead of unkown_prop if no prop was found.

src/common/expression/AttributeExpression.cpp

@@ -51,7 +51,7 @@ const Value &AttributeExpression::eval(ExpressionContext &ctx) {
       }
       auto iter = lvalue.getEdge().props.find(rvalue.getStr());
       if (iter == lvalue.getEdge().props.end()) {
-        return Value::kNullUnknownProp;
+        return Value::kNullValue;
       }
       return iter->second;
     }

tests/tck/features/match/With.feature

@@ -320,3 +320,58 @@ Feature: With clause
       RETURN a
       """
     Then a SemanticError should be raised at runtime:  Alias `b` not defined
+
+  Scenario: condition on nonexist prop
+    Given an empty graph
+    And having executed:
+      """
+      DROP SPACE `nebula_huskie`;
+      CREATE SPACE IF NOT EXISTS `nebula_huskie` (partition_num = 32, replica_factor = 1, charset = utf8, collate = utf8_bin, vid_type = INT64, atomic_edge = false);
+      """
+    And having executed:
+      """
+      USE `nebula_huskie`
+      """
+    And having executed:
+      """
+      CREATE EDGE IF NOT EXISTS `EDGE_0` (`edgeProp_0_0` bool NULL, `edgeProp_0_1` bool NULL, `edgeProp_0_2` float NULL,
+      `edgeProp_0_3` string NULL, `edgeProp_0_4` float NULL)
+      ttl_duration = 0, ttl_col = ""
+      """
+    And having executed:
+      """
+      CREATE EDGE IF NOT EXISTS `EDGE_1` (`edgeProp_1_0` bool NULL) ttl_duration = 0, ttl_col = ""
+      """
+    And having executed:
+      """
+      CREATE TAG IF NOT EXISTS `Label_0` (`labelProp_0_0` float NULL, `labelProp_0_1` string NULL, `labelProp_0_2` bool NULL, `labelProp_0_3` string NULL) ttl_duration = 0, ttl_col = ""
+      """
+    And wait 3 seconds
+    And having executed:
+      """
+      insert vertex Label_0(labelProp_0_0, labelProp_0_1, labelProp_0_2, labelProp_0_3) values 100:(0.5402889847755432,"Rajon Rondo",true,"Shaquile O'Neal");
+      insert vertex Label_0(labelProp_0_0, labelProp_0_1, labelProp_0_2, labelProp_0_3) values 101:(0.5402889847755432,"Rajon Rondo",true,"Shaquile O'Neal");
+      insert edge EDGE_0 values 100->101:(true, false, 0.9068049788475037, "Yao Ming", 0.906804);
+      insert edge EDGE_1 values 100->101:(true);
+      """
+    When executing query:
+      """
+      Match p = (v)-[e]->(t) where id(v) in [100] and e.edgeProp_1_0 == true with e as e, t as t where e.edgeProp_1_0 == true return e;
+      """
+    Then the result should be, in any order:
+      | e                                          |
+      | [:EDGE_1 100->101 @0 {edgeProp_1_0: true}] |
+    When executing query:
+      """
+      match p = (v)-[e]->(t) where id(v) in [100] and e.edgeProp_0_0 == true with e as e, t as t where e.edgeProp_0_0 == true return e.edgeProp_0_0;
+      """
+    Then the result should be, in any order:
+      | e.edgeProp_0_0  |
+      | true            |
+    When executing query:
+      """
+      match p = (v)-[e]->(t) where id(v) in [100] and e.edgeProp_0_0 == true with e as e, t as t where e.edgeProp_0_0 == true return e.edgeProp_1_0;
+      """
+    Then the result should be, in any order:
+      | e.edgeProp_1_0  |
+      | NULL            |