fix enlarged error redaction

[xhebox]

Bug Report

ref #51306

Errors of errStrForLog, handleAssertionFailure is already redacted, and we should not redact it again.

tidb/pkg/server/conn.go

Lines 1166 to 1181 in d2eb902

	func errStrForLog(err error, redactMode string) string {
	if redactMode == errors.RedactLogEnable {
	// currently, only ErrParse is considered when enableRedactLog because it may contain sensitive information like
	// password or accesskey
	if parser.ErrParse.Equal(err) {
	return "fail to parse SQL and can't redact when enable log redaction"
	}
	}
	var ret string
	if kv.ErrKeyExists.Equal(err) || parser.ErrParse.Equal(err) || infoschema.ErrTableNotExists.Equal(err) {
	// Do not log stack for duplicated entry error.
	ret = err.Error()
	} else {
	ret = errors.ErrorStack(err)
	}
	return redact.String(redactMode, ret)

1. Minimal reproduce step (Required)

mysql> create table t (a int, unique key (a));
Query OK, 0 rows affected (0.00 sec)

mysql> insert into t values (1),(1);
ERROR 1062 (23000): Duplicate entry '1' for key 'a'
mysql> set @@session.tidb_redact_log=1;
Query OK, 0 rows affected (0.00 sec)

mysql> insert into t values (1),(1);
ERROR 1062 (23000): Duplicate entry '?' for key '?'

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

[2024/04/07 11:09:34.014 +08:00] [INFO] [conn.go:1147] ["command dispatched failed"] [conn=2097154] [session_alias=] [connInfo="id:2097154, addr:[::1]:46506 status:10, collation:utf8mb4_general_ci, user:root"] [command=Query] [status="inTxn:0, autocommit:1"] [sql="insert into `t` values ( ‹1› ) , ( ‹1› )"] [txn_mode=PESSIMISTIC] [timestamp=448910950141526016] [err="[kv:1062]Duplicate entry '‹1›' for key 't.a'"]

3. What did you see instead (Required)

[2024/04/07 11:09:34.014 +08:00] [INFO] [conn.go:1147] ["command dispatched failed"] [conn=2097154] [session_alias=] [connInfo="id:2097154, addr:[::1]:46506 status:10, collation:utf8mb4_general_ci, user:root"] [command=Query] [status="inTxn:0, autocommit:1"] [sql="insert into `t` values ( ‹1› ) , ( ‹1› )"] [txn_mode=PESSIMISTIC] [timestamp=448910950141526016] [err="‹[kv:1062]Duplicate entry '‹‹1››' for key 't.a'›"]

4. What is your TiDB version? (Required)

master