connect.json fails with valgrind warnings #2

$ perl ./mtr connect.json --valgrind-mysqld

...

==30673== Thread 4:

==30673== Source and destination overlap in strncpy(0xe1e9f3d, 0xe1e9f3d, 15)

==30673==    at 0x4C2A462: __GI_strncpy (vg_replace_strmem.c:494)

==30673==    by 0xCD68BB3: TYPVAL<char*>::SetValue_pval(VALUE*, bool) (value.cpp:1328)

==30673==    by 0xCD4286B: JSONCOL::ReadColumn(_global*) (tabjson.cpp:633)

==30673==    by 0xCCFF97D: COLBLK::Eval(_global*) (colblk.cpp:140)

==30673==    by 0xCCF38C3: EvalColumns(_global*, TDB*, bool, bool) (connect.cc:421)

==30673==    by 0xCCF3AE3: CntReadNext(_global*, TDB*) (connect.cc:473)

==30673==    by 0xCCE78DC: ha_connect::rnd_next(unsigned char*) (ha_connect.cc:3645)

==30673==    by 0x86FDBF: handler::ha_rnd_next(unsigned char*) (handler.cc:2556)

==30673==    by 0x99EEB8: rr_sequential(READ_RECORD*) (records.cc:466)

==30673==    by 0x6DDF9B: join_init_read_record(st_join_table*) (sql_select.cc:18694)

==30673==    by 0x6DBF11: sub_select(JOIN*, st_join_table*, bool) (sql_select.cc:17801)

==30673==    by 0x6DB7D8: do_select(JOIN*, List<Item>*, TABLE*, Procedure*) (sql_select.cc:17466)

==30673==    by 0x6B8C52: JOIN::exec_inner() (sql_select.cc:3081)

==30673==    by 0x6B6167: JOIN::exec() (sql_select.cc:2370)

==30673==    by 0x6B94FC: mysql_select(THD*, Item***, 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:3310)

==30673==    by 0x6AFACC: handle_select(THD*, LEX*, select_result*, unsigned long) (sql_select.cc:373)

==30673== Source and destination overlap in strncpy(0xe1ea6af, 0xe1ea6af, 128)

==30673==    at 0x4C2A462: __GI_strncpy (vg_replace_strmem.c:494)

==30673==    by 0xCD68BB3: TYPVAL<char*>::SetValue_pval(VALUE*, bool) (value.cpp:1328)

==30673==    by 0xCD42647: JSONCOL::SetJsonValue(_global*, VALUE*, JVALUE*, int) (tabjson.cpp:600)

==30673==    by 0xCD42F8A: JSONCOL::ExpandArray(_global*, JARRAY*, int) (tabjson.cpp:736)

==30673==    by 0xCD42B7F: JSONCOL::GetColumnValue(_global*, JSON*, int) (tabjson.cpp:674)

==30673==    by 0xCD42853: JSONCOL::ReadColumn(_global*) (tabjson.cpp:633)

==30673==    by 0xCCFF97D: COLBLK::Eval(_global*) (colblk.cpp:140)

==30673==    by 0xCCF38C3: EvalColumns(_global*, TDB*, bool, bool) (connect.cc:421)

==30673==    by 0xCCF3AE3: CntReadNext(_global*, TDB*) (connect.cc:473)

==30673==    by 0xCCE78DC: ha_connect::rnd_next(unsigned char*) (ha_connect.cc:3645)

==30673==    by 0x86FDBF: handler::ha_rnd_next(unsigned char*) (handler.cc:2556)

==30673==    by 0x99EEB8: rr_sequential(READ_RECORD*) (records.cc:466)

==30673==    by 0x6DDF9B: join_init_read_record(st_join_table*) (sql_select.cc:18694)

==30673==    by 0x6DBF11: sub_select(JOIN*, st_join_table*, bool) (sql_select.cc:17801)

==30673==    by 0x6DB7D8: do_select(JOIN*, List<Item>*, TABLE*, Procedure*) (sql_select.cc:17466)

==30673==    by 0x6B8C52: JOIN::exec_inner() (sql_select.cc:3081)