MDEV-34305 Redundant truncation errors/warnings with optimizer_trace enabled

my_like_range*() can create longer keys than Field::char_length().
This caused warnings during print_range().

Fix:

Suppressing warnings in print_range().

mysql-test/main/opt_trace.result

@@ -9280,5 +9280,33 @@ select QUERY, LENGTH(trace)>1 from information_schema.optimizer_trace;
 QUERY	LENGTH(trace)>1
 insert into t2 select * from t1 where a<= b and a>4	1
 drop table t1, t2;
+#
+# MDEV-34305 Redundant truncation errors/warnings with optimizer_trace enabled
+#
+SET @@optimizer_trace='enabled=on';
+CREATE TABLE t1 (
+a CHAR(2) NOT NULL PRIMARY KEY,
+b VARCHAR(20) NOT NULL,
+KEY (b)
+) CHARSET=utf8mb4;
+CREATE TABLE t2 (
+a CHAR(2) NOT NULL PRIMARY KEY,
+b VARCHAR(20) NOT NULL,
+KEY (b)
+) CHARSET=utf8mb4;
+INSERT INTO t1 VALUES
+('AB','MySQLAB'),
+('JA','Sun Microsystems'),
+('MS','Microsoft'),
+('IB','IBM- Inc.'),
+('GO','Google Inc.');
+INSERT IGNORE INTO t2 VALUES
+('AB','Sweden'),
+('JA','USA'),
+('MS','United States'),
+('IB','North America'),
+('GO','South America');
+UPDATE t1,t2 SET t1.b=UPPER(t1.b) WHERE t1.b LIKE 'Unknown%';
+DROP TABLE t1, t2;
 # End of 10.5 tests
 set optimizer_trace='enabled=off';

mysql-test/main/opt_trace.test

@@ -971,5 +971,40 @@ select QUERY, LENGTH(trace)>1 from information_schema.optimizer_trace;
 
 drop table t1, t2;
 
+--echo #
+--echo # MDEV-34305 Redundant truncation errors/warnings with optimizer_trace enabled
+--echo #
+
+SET @@optimizer_trace='enabled=on';
+
+CREATE TABLE t1 (
+  a CHAR(2) NOT NULL PRIMARY KEY,
+  b VARCHAR(20) NOT NULL,
+  KEY (b)
+) CHARSET=utf8mb4;
+
+CREATE TABLE t2 (
+  a CHAR(2) NOT NULL PRIMARY KEY,
+  b VARCHAR(20) NOT NULL,
+  KEY (b)
+) CHARSET=utf8mb4;
+
+INSERT INTO t1 VALUES
+('AB','MySQLAB'),
+('JA','Sun Microsystems'),
+('MS','Microsoft'),
+('IB','IBM- Inc.'),
+('GO','Google Inc.');
+
+INSERT IGNORE INTO t2 VALUES
+('AB','Sweden'),
+('JA','USA'),
+('MS','United States'),
+('IB','North America'),
+('GO','South America');
+
+UPDATE t1,t2 SET t1.b=UPPER(t1.b) WHERE t1.b LIKE 'Unknown%';
+DROP TABLE t1, t2;
+
 --echo # End of 10.5 tests
 set optimizer_trace='enabled=off';

sql/opt_range.cc

@@ -16453,6 +16453,7 @@ static
 void print_range(String *out, const KEY_PART_INFO *key_part,
                  KEY_MULTI_RANGE *range, uint n_key_parts)
 {
+  Check_level_instant_set check_field(current_thd, CHECK_FIELD_IGNORE);
   uint flag= range->range_flag;
   String key_name;
   key_name.set_charset(system_charset_info);