Unexpected exception for json_extract: None const type of json path argument of function json_extract, e.what() = DB::Exception,

[SeaRise]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)

drop table if exists test.t_json;
create table test.t_json(col_json json);
alter table test.t_json set tiflash replica 1;
insert into test.t_json values(null), ('[]'), ('{}'), ('{\"a\":{\"c\":{}, \"d\":{}}, \"b\":{\"e\":{}, \"f\":{}}}'); #NO_UNESCAPE

drop table if exists test.t_path;
create table test.t_path(col_path varchar(100));
alter table test.t_path set tiflash replica 1;
insert into test.t_path values(null), ('$'), ('\$[0]'), ('\$[1]'), ('\$.a'), ('\$.b'); #NO_UNESCAPE

set tidb_allow_mpp=1;
set tidb_enforce_mpp=1; 
set tidb_isolation_read_engines='tiflash'; 
select col_json, col_path, json_extract(col_json, col_path) as res from (select * from test.t_json join test.t_path) t order by col_json, col_path;

2. What did you expect to see? (Required)

query success

3. What did you see instead (Required)

ERROR 1105 (HY000): other error for mpp stream: Code: 43, e.displayText() = DB::Exception: None const type of json path argument of function json_extract, e.what() = DB::Exception,

4. What is your TiFlash version? (Required)

8.0.11-TiDB-v7.6.0-alpha

[SeaRise]

/cc @yibin87

[yibin87]

Yeah, it is expected since it's very corner case and doesn't make much sense to use column as path arguments.

[SeaRise]

Okay, so the severity is set to minor level.