Json_writer::add_bool: Conditional jump or move depends on uninitialised value upon fulltext search under optimizer trace

CREATE TABLE t1 (f VARCHAR(255), FULLTEXT(f));

CREATE VIEW v1 AS SELECT * FROM t1;

# Optional, fails either way

INSERT INTO t1 VALUES ('foo'),('bar');

SET optimizer_trace = 'enabled=on';

SELECT COUNT(*) FROM v1 WHERE MATCH (f) AGAINST ('scenario' IN NATURAL LANGUAGE MODE);

# Cleanup

DROP VIEW v1;

DROP TABLE t1;

==27879== Thread 6:

==27879== Conditional jump or move depends on uninitialised value(s)

==27879==    at 0xA88543: Json_writer::add_bool(bool) (my_json_writer.cc:163)

==27879==    by 0x92ED1B: Json_value_helper::add_bool(bool) (my_json_writer.h:298)

==27879==    by 0x92EDFF: Json_writer_object::add(char const*, bool) (my_json_writer.h:362)

==27879==    by 0x989B72: print_keyuse_array_for_trace(THD*, st_dynamic_array*) (sql_test.cc:676)

==27879==    by 0x8E84F6: make_join_statistics(JOIN*, List<TABLE_LIST>&, st_dynamic_array*) (sql_select.cc:4985)

==27879==    by 0x8DE571: JOIN::optimize_inner() (sql_select.cc:2174)

==27879==    by 0x8DC057: JOIN::optimize() (sql_select.cc:1551)

==27879==    by 0x8E70E3: mysql_select(THD*, TABLE_LIST*, unsigned int, List<Item>&, Item*, unsigned int, st_order*, st_order*, Item*, st_order*, unsigned long long, select_result*, st_select_lex_unit*, st_select_lex*) (sql_select.cc:4571)

==27879==    by 0x8D7567: handle_select(THD*, LEX*, select_result*, unsigned long) (sql_select.cc:424)

==27879==    by 0x89FCC2: execute_sqlcom_select(THD*, TABLE_LIST*) (sql_parse.cc:6652)

==27879==    by 0x894E7D: mysql_execute_command(THD*) (sql_parse.cc:3889)

==27879==    by 0x8A3C02: mysql_parse(THD*, char*, unsigned int, Parser_state*, bool, bool) (sql_parse.cc:8205)

==27879==    by 0x88F0E6: dispatch_command(enum_server_command, THD*, char*, unsigned int, bool, bool) (sql_parse.cc:1829)

==27879==    by 0x88D8CC: do_command(THD*) (sql_parse.cc:1358)

==27879==    by 0xA0D6C0: do_handle_one_connection(CONNECT*) (sql_connect.cc:1399)

==27879==    by 0xA0D431: handle_one_connection (sql_connect.cc:1302)