json, expr: json_search should return NULL when the search path is NULL (pingcap#59714)

close pingcap#59463

Author: YangKeao

pkg/expression/builtin_json_vec.go

@@ -565,11 +565,14 @@ func (b *builtinJSONSearchSig) vecEvalJSON(ctx EvalContext, input *chunk.Chunk,
 				return errIncorrectArgs.GenWithStackByArgs("ESCAPE")
 			}
 		}
+
+		var isNull bool
 		var pathExprs []types.JSONPathExpression
 		if pathBufs != nil {
 			pathExprs = make([]types.JSONPathExpression, 0, len(b.args)-4)
 			for j := 0; j < len(b.args)-4; j++ {
 				if pathBufs[j].IsNull(i) {
+					isNull = true
 					break
 				}
 				pathExpr, err := types.ParseJSONPathExpr(pathBufs[j].GetString(i))
@@ -579,6 +582,11 @@ func (b *builtinJSONSearchSig) vecEvalJSON(ctx EvalContext, input *chunk.Chunk,
 				pathExprs = append(pathExprs, pathExpr)
 			}
 		}
+		if isNull {
+			result.AppendNull()
+			continue
+		}
+
 		bj, isNull, err := jsonBuf.GetJSON(i).Search(containType, searchBuf.GetString(i), escape, pathExprs)
 		if err != nil {
 			return err

tests/integrationtest/r/expression/json.result

@@ -864,3 +864,12 @@ json_set('{"a":"b"}', '$[last]', 1)
 SELECT JSON_ARRAY_APPEND('[1]', '$', JSON_ARRAY(2, 3));
 JSON_ARRAY_APPEND('[1]', '$', JSON_ARRAY(2, 3))
 [1, [2, 3]]
+set tidb_enable_vectorized_expression = 'ON';
+select json_search('{"h": "i"}', 'all', 'i', '\\', NULL);
+json_search('{"h": "i"}', 'all', 'i', '\\', NULL)
+NULL
+set tidb_enable_vectorized_expression = 'OFF';
+select json_search('{"h": "i"}', 'all', 'i', '\\', NULL);
+json_search('{"h": "i"}', 'all', 'i', '\\', NULL)
+NULL
+set tidb_enable_vectorized_expression = default;

tests/integrationtest/t/expression/json.test

@@ -568,3 +568,11 @@ select json_set('{"a":"b"}', '$[last]', 1);
 
 # TestIssue59465
 SELECT JSON_ARRAY_APPEND('[1]', '$', JSON_ARRAY(2, 3));
+
+# TestIssue59463
+# should return NULL because the path is NULL
+set tidb_enable_vectorized_expression = 'ON';
+select json_search('{"h": "i"}', 'all', 'i', '\\', NULL);
+set tidb_enable_vectorized_expression = 'OFF';
+select json_search('{"h": "i"}', 'all', 'i', '\\', NULL);
+set tidb_enable_vectorized_expression = default;