UBSAN: runtime error: applying zero offset to null pointer in my_uca_contraction_find on SET SESSION collation_connection

SET SESSION collation_connection=utf8_german2_ci;

/test/10.5_opt_san/strings/ctype-uca.c:31493:31: runtime error: applying zero offset to null pointer

SUMMARY: UndefinedBehaviorSanitizer: nullptr-with-offset /test/10.5_opt_san/strings/ctype-uca.c:31493:31 

    #0 0x559d9ea8d742 in my_uca_contraction_find /test/10.5_opt_san/strings/ctype-uca.c:31493:31

    #1 0x559d9ea8ce80 in my_char_weight_put /test/10.5_opt_san/strings/ctype-uca.c:33243:17

    #2 0x559d9ea85bdb in apply_one_rule /test/10.5_opt_san/strings/ctype-uca.c:33515:9

    #3 0x559d9ea85bdb in init_weight_level /test/10.5_opt_san/strings/ctype-uca.c:33719:9

    #4 0x559d9ea85bdb in create_tailoring /test/10.5_opt_san/strings/ctype-uca.c:33888:14

    #5 0x559d9ea6e3a9 in my_coll_init_uca /test/10.5_opt_san/strings/ctype-uca.c:33755:10

    #6 0x559d9ea6e3a9 in my_uca_coll_init_utf8mb3 /test/10.5_opt_san/strings/ctype-uca.c:34897:7

    #7 0x559d9e92d202 in my_ci_init_collation /test/10.5_opt_san/include/m_ctype.h:1121:10

    #8 0x559d9e92d202 in get_internal_charset /test/10.5_opt_san/mysys/charset.c:885:13

    #9 0x559d9e92dfa8 in my_collation_get_by_name /test/10.5_opt_san/mysys/charset.c:950:19

    #10 0x559d9e92dfa8 in get_charset_by_name /test/10.5_opt_san/mysys/charset.c:966:10

    #11 0x559d9c678bdb in check_collation_not_null(sys_var*, THD*, set_var*) /test/10.5_opt_san/sql/sys_vars.cc:887:35

    #12 0x559d9ba28529 in sys_var::check(THD*, set_var*) /test/10.5_opt_san/sql/set_var.cc:248:7

    #13 0x559d9ba30c29 in set_var::check(THD*) /test/10.5_opt_san/sql/set_var.cc:815:15

    #14 0x559d9ba2f51a in sql_set_variables(THD*, List<set_var_base>*, bool) /test/10.5_opt_san/sql/set_var.cc:743:9

    #15 0x559d9bf329b4 in mysql_execute_command(THD*) /test/10.5_opt_san/sql/sql_parse.cc:5186:9

    #16 0x559d9befee98 in mysql_parse(THD*, char*, unsigned int, Parser_state*, bool, bool) /test/10.5_opt_san/sql/sql_parse.cc:8251:18

    #17 0x559d9bef19d0 in dispatch_command(enum_server_command, THD*, char*, unsigned int, bool, bool) /test/10.5_opt_san/sql/sql_parse.cc:1891:7

    #18 0x559d9bf018d9 in do_command(THD*) /test/10.5_opt_san/sql/sql_parse.cc:1375:17

    #19 0x559d9c6095c2 in do_handle_one_connection(CONNECT*, bool) /test/10.5_opt_san/sql/sql_connect.cc:1386:11

    #20 0x559d9c608a24 in handle_one_connection /test/10.5_opt_san/sql/sql_connect.cc:1298:5

    #21 0x559d9b96910c in asan_thread_start(void*) asan_interceptors.cpp.o

    #22 0x15223fa9ca93 in start_thread nptl/pthread_create.c:447:8

    #23 0x15223fb29c3b in clone3 misc/../sysdeps/unix/sysv/linux/x86_64/clone3.S:78

SUMMARY: UndefinedBehaviorSanitizer: nullptr-with-offset /test/10.5_opt_san/strings/ctype-uca.c:31493:31 

Compiled with a recent version of Clang (I used Clang 18.1.3) with LLVM 18:

     # Note: llvm-17-linker-tools installs /usr/lib/llvm-17/lib/LLVMgold.so, which is needed for compilation, and LLVMgold.so is no longer included in LLVM 18

     sudo apt install clang llvm-18 llvm-18-linker-tools llvm-18-runtime llvm-18-tools llvm-18-dev libstdc++-14-dev llvm-dev llvm-17-linker-tools

     sudo ln -s /usr/lib/llvm-17/lib/LLVMgold.so /usr/lib/llvm-18/lib/LLVMgold.so

Compiled with: '-DCMAKE_C_COMPILER=/usr/bin/clang -DCMAKE_CXX_COMPILER=/usr/bin/clang++' and:

    -DWITH_ASAN=ON -DWITH_ASAN_SCOPE=ON -DWITH_UBSAN=ON -DWSREP_LIB_WITH_ASAN=ON

Set before execution:

    export UBSAN_OPTIONS=print_stacktrace=1:report_error_type=1   # And you may also want to supress UBSAN startup issues using 'suppressions=UBSAN.filter'. For an example of UBSAN.filter, which includes current startup issues see: https://github.com/mariadb-corporation/mariadb-qa/blob/master/UBSAN.filter