Invalid sys.config results in code server crash #10214
Description
Describe the bug
When a sys.config is just a number followed by a letter (e.g. 7k), Erlang will crash with an obscure message not referencing the configuration or a line number at all:
$ erl -config sys
2025-09-18 11:54:22.548561 {error,simple_handler_process_dead}
2025-09-18 11:54:22.548391 Error in process ~p with exit value:~n~p~n
<0.49.0>
{undef,[{logger_formatter,format,[#{meta=>#{error_logger=>#{emulator=>true,tag=>error},pid=><0.45.0>,time=>1758189262547649,gl=><0.0.0>},msg=>{"Error in process ~p with exit value:~n~p~n",[<0.45.0>,{badarg,[{erlang,send,[code_server,{code_call,<0.45.0>,{finish_loading,[],true}}],[{error_info,#{module=>erl_erts_errors}}]},{code_server,call,1,[{file,"code_server.erl"},{line,163}]},{code,ensure_modules_loaded_1,1,[{file,"code.erl"},{line,1322}]},{io_lib,test_modules_loaded,3,[{file,"io_lib.erl"},{line,462}]},{io_lib,format,2,[{file,"io_lib.erl"},{line,338}]},{application_controller,init,2,[{file,"application_controller.erl"},{line,559}]}]}]},level=>error},#{time_offset=>[],depth=>unlimited,single_line=>false,legacy_header=>true}],[]},{logger_simple_h,'-log_internal/2-fun-0-',1,[{file,"logger_simple_h.erl"},{line,174}]}]}
Could not start kernel pid (application_controller) ("{badarg,[{erlang,send,[code_server,{code_call,<0.45.0>,{finish_loading,[],true}}],[{error_info,#{module => erl_erts_errors}}]},{code_server,call,1,[{file,\"code_server.erl\"},{line,163}]},{code,ensure_modules_loaded_1,1,[{file,\"code.erl\"},{line,1322}]},{io_lib,test_modules_loaded,3,[{file,\"io_lib.erl\"},{line,462}]},{io_lib,format,2,[{file,\"io_lib.erl\"},{line,338}]},{application_controller,init,2,[{file,\"application_controller.erl\"},{line,559}]}]}")
Crash dump is being written to: erl_crash.dump...doneTo Reproduce
- Create a
sys.configfile with this content:7k - Start Erlang
erl -config sysin the same directory - Erlang crashes
Expected behavior
Erlang reports a syntax error on the line where the error occurs.
Affected versions
28.0-28.1
(27 and below seems to work).
Additional context
We discovered this when templating long complicated sys.config files containing RSA private keys that were not correctly enclosed in Erlang syntax. It took us a really long time figuring out that this was a problem.
Erlang 27 and 28 seems to handle this syntax differently:
28:
Erlang/OTP 28 [erts-16.0.2] [source] [64-bit] [smp:12:12] [ds:12:12:10] [async-threads:1] [jit]
Eshell V16.0.2 (press Ctrl+G to abort, type help(). for help)
1> 7k
k
* 1:1: illegal integer
27:
Erlang/OTP 27 [erts-15.2.7.2] [source] [64-bit] [smp:12:12] [ds:12:12:10] [async-threads:1] [jit]
Eshell V15.2.7.2 (press Ctrl+G to abort, type help(). for help)
1> 7k
.
* 1:2: syntax error before: k