Bug #20996: Embed Ruby 3.4 Failure

• Status: Closed
• Assignee: -
• Target version: -
• ruby -v: ruby 3.4.1 (2024-12-25 revision 48d4efcb85) +PRISM
• Backport: 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN, 3.4: UNKNOWN

[cfis (Charlie Savage)]

Rice embeds Ruby in order to run its tests. This code has worked across multiple Ruby versions (current tests are 3.1, 3.2, 3.3 and 3.4 but previously tests were run on 3.0 and 2.x). However, it fails on 3.4 in different ways on different operating systems.

The code is here - https://github.com/ruby-rice/rice/blob/master/test/embed_ruby.cpp#L10.

int argc = 0;
char* argv = nullptr;
char** pArgv = &argv;

// ruby_sysinit(&argc, &pArgv);
ruby_init();
ruby_init_loadpath();

#if RUBY_API_VERSION_MAJOR == 3 && RUBY_API_VERSION_MINOR >= 1
// Force the prelude / builtins
const char* opts[] = { "ruby", "-e;" };
ruby_options(2, (char**)opts);
#endif

The test suite is here:

https://github.com/ruby-rice/rice/actions/runs/12534403540/job/35007888873

With Ruby 3.4 on Fedora this fails with the following stack trace:

libruby.so.3.4!str_gsub(int argc, VALUE * argv, VALUE str, int bang) (\home\cfis\.rbenv\sources\3.4.1\ruby-3.4.1\string.c:6348)
libruby.so.3.4!vm_call_cfunc_with_frame_(rb_execution_context_t * ec, rb_control_frame_t * reg_cfp, struct rb_calling_info * calling, int argc, VALUE * argv, VALUE * stack_bottom) (\home\cfis\.rbenv\sources\3.4.1\ruby-3.4.1\vm_insnhelper.c:3801)
libruby.so.3.4!vm_call_cfunc_with_frame(rb_execution_context_t * ec, rb_control_frame_t * reg_cfp, struct rb_calling_info * calling) (\home\cfis\.rbenv\sources\3.4.1\ruby-3.4.1\vm_insnhelper.c:3847)
libruby.so.3.4!vm_sendish(struct rb_execution_context_struct * ec, struct rb_control_frame_struct * reg_cfp, struct rb_call_data * cd, VALUE block_handler) (\home\cfis\.rbenv\sources\3.4.1\ruby-3.4.1\vm_callinfo.h:415)
libruby.so.3.4!vm_exec_core(rb_execution_context_t * ec, rb_execution_context_t * ec@entry) (\home\cfis\.rbenv\sources\3.4.1\ruby-3.4.1\insns.def:851)
libruby.so.3.4!vm_exec_loop(enum ruby_tag_type state, VALUE result) (\home\cfis\.rbenv\sources\3.4.1\ruby-3.4.1\vm.c:2622)
libruby.so.3.4!rb_vm_exec(rb_execution_context_t * ec) (\home\cfis\.rbenv\sources\3.4.1\ruby-3.4.1\vm.c:2598)
libruby.so.3.4!vm_yield_with_cref(int is_lambda, rb_execution_context_t * ec, int argc, const VALUE * argv, int kw_splat, const rb_cref_t * cref) (\home\cfis\.rbenv\sources\3.4.1\ruby-3.4.1\vm.c:1670)
libruby.so.3.4!vm_yield(rb_execution_context_t * ec, int argc, const VALUE * argv, int kw_splat) (\home\cfis\.rbenv\sources\3.4.1\ruby-3.4.1\vm.c:1684)
libruby.so.3.4!rb_yield_0(int argc, const VALUE * argv) (\home\cfis\.rbenv\sources\3.4.1\ruby-3.4.1\vm_eval.c:1344)
libruby.so.3.4!rb_yield(VALUE val) (\home\cfis\.rbenv\sources\3.4.1\ruby-3.4.1\vm_eval.c:1360)
libruby.so.3.4!each_value_i(VALUE key, VALUE value, VALUE _) (\home\cfis\.rbenv\sources\3.4.1\ruby-3.4.1\hash.c:3015)
libruby.so.3.4!hash_foreach_iter(st_data_t key, st_data_t key@entry, st_data_t value, st_data_t argp, st_data_t argp@entry, int error, int error@entry) (\home\cfis\.rbenv\sources\3.4.1\ruby-3.4.1\hash.c:1316)
libruby.so.3.4!st_general_foreach(st_table * tab, st_table * tab@entry, st_foreach_check_callback_func * func, st_data_t arg) (\home\cfis\.rbenv\sources\3.4.1\ruby-3.4.1\st.c:1543)
libruby.so.3.4!rb_st_foreach_check(st_table * tab, st_table * tab@entry, st_foreach_check_callback_func * func, st_foreach_check_callback_func * func@entry, st_data_t arg, st_data_t arg@entry, st_data_t never, st_data_t never@entry) (\home\cfis\.rbenv\sources\3.4.1\ruby-3.4.1\st.c:1648)
libruby.so.3.4!hash_foreach_call(VALUE arg, VALUE arg@entry) (\home\cfis\.rbenv\sources\3.4.1\ruby-3.4.1\hash.c:1439)
libruby.so.3.4!rb_ensure(VALUE (*)(VALUE) b_proc, VALUE (*)(VALUE) b_proc@entry, VALUE data1, VALUE data1@entry, VALUE (*)(VALUE) e_proc, VALUE (*)(VALUE) e_proc@entry, VALUE data2, VALUE data2@entry) (\home\cfis\.rbenv\sources\3.4.1\ruby-3.4.1\eval.c:1074)
libruby.so.3.4!rb_hash_foreach(VALUE hash, VALUE hash@entry, rb_foreach_func * func, rb_foreach_func * func@entry, VALUE farg, VALUE farg@entry) (\home\cfis\.rbenv\sources\3.4.1\ruby-3.4.1\hash.c:1463)
libruby.so.3.4!rb_hash_each_value(VALUE hash) (\home\cfis\.rbenv\sources\3.4.1\ruby-3.4.1\hash.c:3047)
libruby.so.3.4!vm_call_cfunc_with_frame_(rb_execution_context_t * ec, rb_control_frame_t * reg_cfp, struct rb_calling_info * calling, int argc, VALUE * argv, VALUE * stack_bottom) (\home\cfis\.rbenv\sources\3.4.1\ruby-3.4.1\vm_insnhelper.c:3801)
libruby.so.3.4!vm_sendish(struct rb_execution_context_struct * ec, struct rb_control_frame_struct * reg_cfp, struct rb_call_data * cd, VALUE block_handler) (\home\cfis\.rbenv\sources\3.4.1\ruby-3.4.1\vm_callinfo.h:415)
libruby.so.3.4!vm_exec_core(rb_execution_context_t * ec, rb_execution_context_t * ec@entry) (\home\cfis\.rbenv\sources\3.4.1\ruby-3.4.1\insns.def:851)
libruby.so.3.4!vm_exec_loop(enum ruby_tag_type state, VALUE result) (\home\cfis\.rbenv\sources\3.4.1\ruby-3.4.1\vm.c:2622)
libruby.so.3.4!rb_vm_exec(rb_execution_context_t * ec) (\home\cfis\.rbenv\sources\3.4.1\ruby-3.4.1\vm.c:2598)
libruby.so.3.4!rb_iseq_eval(const rb_iseq_t * iseq, const rb_iseq_t * iseq@entry) (\home\cfis\.rbenv\sources\3.4.1\ruby-3.4.1\vm.c:2850)
libruby.so.3.4!load_iseq_eval(rb_execution_context_t * ec, VALUE fname) (\home\cfis\.rbenv\sources\3.4.1\ruby-3.4.1\load.c:789)
libruby.so.3.4!require_internal(rb_execution_context_t * ec, rb_execution_context_t * ec@entry, VALUE fname, VALUE fname@entry, int exception, int exception@entry, _Bool warn) (\home\cfis\.rbenv\sources\3.4.1\ruby-3.4.1\load.c:1296)
libruby.so.3.4!rb_require_string_internal(VALUE fname) (\home\cfis\.rbenv\sources\3.4.1\ruby-3.4.1\load.c:1402)
libruby.so.3.4!rb_require_string(VALUE fname) (\home\cfis\.rbenv\sources\3.4.1\ruby-3.4.1\load.c:1388)
libruby.so.3.4!vm_call_cfunc_with_frame_(rb_execution_context_t * ec, rb_control_frame_t * reg_cfp, struct rb_calling_info * calling, int argc, VALUE * argv, VALUE * stack_bottom) (\home\cfis\.rbenv\sources\3.4.1\ruby-3.4.1\vm_insnhelper.c:3801)
libruby.so.3.4!vm_call_cfunc_with_frame(rb_execution_context_t * ec, rb_control_frame_t * reg_cfp, struct rb_calling_info * calling) (\home\cfis\.rbenv\sources\3.4.1\ruby-3.4.1\vm_insnhelper.c:3847)
libruby.so.3.4!vm_sendish() (\home\cfis\.rbenv\sources\3.4.1\ruby-3.4.1\vm_callinfo.h:415)
libruby.so.3.4!vm_exec_core(rb_execution_context_t * ec, rb_execution_context_t * ec@entry) (\home\cfis\.rbenv\sources\3.4.1\ruby-3.4.1\insns.def:898)
libruby.so.3.4!vm_exec_loop(enum ruby_tag_type state, VALUE result) (\home\cfis\.rbenv\sources\3.4.1\ruby-3.4.1\vm.c:2622)
libruby.so.3.4!rb_vm_exec(rb_execution_context_t * ec) (\home\cfis\.rbenv\sources\3.4.1\ruby-3.4.1\vm.c:2598)
libruby.so.3.4!rb_iseq_eval(const rb_iseq_t * iseq, const rb_iseq_t * iseq@entry) (\home\cfis\.rbenv\sources\3.4.1\ruby-3.4.1\vm.c:2850)
libruby.so.3.4!load_iseq_eval(rb_execution_context_t * ec, VALUE fname) (\home\cfis\.rbenv\sources\3.4.1\ruby-3.4.1\load.c:789)
libruby.so.3.4!require_internal(rb_execution_context_t * ec, rb_execution_context_t * ec@entry, VALUE fname, VALUE fname@entry, int exception, int exception@entry, _Bool warn) (\home\cfis\.rbenv\sources\3.4.1\ruby-3.4.1\load.c:1296)
libruby.so.3.4!rb_require_string_internal(VALUE fname) (\home\cfis\.rbenv\sources\3.4.1\ruby-3.4.1\load.c:1402)
libruby.so.3.4!rb_require_string(VALUE fname) (\home\cfis\.rbenv\sources\3.4.1\ruby-3.4.1\load.c:1388)
libruby.so.3.4!vm_call_cfunc_with_frame_(rb_execution_context_t * ec, rb_control_frame_t * reg_cfp, struct rb_calling_info * calling, int argc, VALUE * argv, VALUE * stack_bottom) (\home\cfis\.rbenv\sources\3.4.1\ruby-3.4.1\vm_insnhelper.c:3801)
libruby.so.3.4!vm_sendish() (\home\cfis\.rbenv\sources\3.4.1\ruby-3.4.1\vm_callinfo.h:415)
libruby.so.3.4!vm_exec_core(rb_execution_context_t * ec, rb_execution_context_t * ec@entry) (\home\cfis\.rbenv\sources\3.4.1\ruby-3.4.1\insns.def:898)
libruby.so.3.4!vm_exec_loop(enum ruby_tag_type state, VALUE result) (\home\cfis\.rbenv\sources\3.4.1\ruby-3.4.1\vm.c:2622)
libruby.so.3.4!rb_vm_exec(rb_execution_context_t * ec) (\home\cfis\.rbenv\sources\3.4.1\ruby-3.4.1\vm.c:2598)
libruby.so.3.4!ruby_init_prelude() (\home\cfis\.rbenv\sources\3.4.1\ruby-3.4.1\ruby.c:1750)
libruby.so.3.4!ruby_opt_init(ruby_cmdline_options_t * opt) (\home\cfis\.rbenv\sources\3.4.1\ruby-3.4.1\ruby.c:1811)
libruby.so.3.4!ruby_opt_init(ruby_cmdline_options_t * opt) (\home\cfis\.rbenv\sources\3.4.1\ruby-3.4.1\ruby.c:1767)
libruby.so.3.4!prism_script(ruby_cmdline_options_t * opt, pm_parse_result_t * result) (\home\cfis\.rbenv\sources\3.4.1\ruby-3.4.1\ruby.c:2199)
libruby.so.3.4!process_options(int argc, int argc@entry, char ** argv, char ** argv@entry, ruby_cmdline_options_t * opt, ruby_cmdline_options_t * opt@entry) (\home\cfis\.rbenv\sources\3.4.1\ruby-3.4.1\ruby.c:2538)
libruby.so.3.4!ruby_process_options(int argc, int argc@entry, char ** argv, char ** argv@entry) (\home\cfis\.rbenv\sources\3.4.1\ruby-3.4.1\ruby.c:228)
libruby.so.3.4!ruby_options(int argc, char ** argv) (\home\cfis\.rbenv\sources\3.4.1\ruby-3.4.1\eval.c:117)
embed_ruby() (\usr\local\src\rice\test\embed_ruby.cpp:21)
fixture__Keep_Alive__setup() (\usr\local\src\rice\test\test_Keep_Alive.cpp:60)
Test_Suite::run(class Test_Suite * const this, class Test_Suite * const this@entry, class Test_Result & result) (\usr\local\src\rice\test\unittest.cpp:61)
main(int argc, char ** argv) (\usr\local\src\rice\test\unittest.cpp:124)

On MacOS, it fails like this (see https://github.com/ruby-rice/rice/actions/runs/12534403540/job/35007888873):

-- C level backtrace information -------------------------------------------
/Users/runner/hostedtoolcache/Ruby/3.4.1/arm64/lib/libruby.3.4.dylib(rb_vm_bugreport+0xb6c) [0x103b1f10c]
/Users/runner/hostedtoolcache/Ruby/3.4.1/arm64/lib/libruby.3.4.dylib(rb_bug_for_fatal_signal+0x100) [0x103957970]
/Users/runner/hostedtoolcache/Ruby/3.4.1/arm64/lib/libruby.3.4.dylib(sigsegv+0x84) [0x103a809d4]
/usr/lib/system/libsystem_platform.dylib(_sigtramp+0x38) [0x19a576584]
/Users/runner/hostedtoolcache/Ruby/3.4.1/arm64/lib/libruby.3.4.dylib(callable_method_entry_or_negative+0xc0) [0x103afbac8]
/Users/runner/hostedtoolcache/Ruby/3.4.1/arm64/lib/libruby.3.4.dylib(rb_vm_search_method_slowpath+0xc8) [0x103aeefa4]
/Users/runner/hostedtoolcache/Ruby/3.4.1/arm64/lib/libruby.3.4.dylib(gccct_method_search_slowpath+0x24) [0x103b0a484]
/Users/runner/hostedtoolcache/Ruby/3.4.1/arm64/lib/libruby.3.4.dylib(rb_funcallv_scope+0x17c) [0x103b002e0]
/Users/runner/hostedtoolcache/Ruby/3.4.1/arm64/lib/libruby.3.4.dylib(rb_funcall+0x88) [0x103b00750]
/Users/runner/hostedtoolcache/Ruby/3.4.1/arm64/lib/libruby.3.4.dylib(rb_obj_as_string+0x44) [0x103a927d4]
/Users/runner/hostedtoolcache/Ruby/3.4.1/arm64/lib/libruby.3.4.dylib(ruby__sfvextra+0xe0) [0x103a8692c]
/Users/runner/hostedtoolcache/Ruby/3.4.1/arm64/lib/libruby.3.4.dylib(BSD_vfprintf+0x60c) [0x103a84a24]
/Users/runner/hostedtoolcache/Ruby/3.4.1/arm64/lib/libruby.3.4.dylib(ruby_vsprintf0+0xa8) [0x103a84100]
/Users/runner/hostedtoolcache/Ruby/3.4.1/arm64/lib/libruby.3.4.dylib(rb_sprintf+0x5c) [0x103a84278]
/Users/runner/hostedtoolcache/Ruby/3.4.1/arm64/lib/libruby.3.4.dylib(unexpected_type+0x64) [0x103c63c64]
/Users/runner/hostedtoolcache/Ruby/3.4.1/arm64/lib/libruby.3.4.dylib(rb_unexpected_type+0x30) [0x103c63cac]
/Users/runner/hostedtoolcache/Ruby/3.4.1/arm64/lib/libruby.3.4.dylib(rb_fstring+0x1a0) [0x103a8f77c]
/Users/runner/hostedtoolcache/Ruby/3.4.1/arm64/lib/libruby.3.4.dylib(require_internal+0x550) [0x1039c37f8]
/Users/runner/hostedtoolcache/Ruby/3.4.1/arm64/lib/libruby.3.4.dylib(rb_require_string_internal+0x58) [0x1039c2b6c]
/Users/runner/hostedtoolcache/Ruby/3.4.1/arm64/lib/libruby.3.4.dylib(rb_f_require+0x44) [0x1039c2a3c]
/Users/runner/hostedtoolcache/Ruby/3.4.1/arm64/lib/libruby.3.4.dylib(vm_call_cfunc_with_frame_+0xf0) [0x103b10ce8]
/Users/runner/hostedtoolcache/Ruby/3.4.1/arm64/lib/libruby.3.4.dylib(vm_exec_core+0x2468) [0x103af4cf0]
/Users/runner/hostedtoolcache/Ruby/3.4.1/arm64/lib/libruby.3.4.dylib(rb_vm_exec+0x1e8) [0x103af136c]
/Users/runner/hostedtoolcache/Ruby/3.4.1/arm64/lib/libruby.3.4.dylib(load_iseq_eval+0x22c) [0x1039c56ac]
/Users/runner/hostedtoolcache/Ruby/3.4.1/arm64/lib/libruby.3.4.dylib(require_internal+0x354) [0x1039c35fc]
/Users/runner/hostedtoolcache/Ruby/3.4.1/arm64/lib/libruby.3.4.dylib(rb_require_string_internal+0x58) [0x1039c2b6c]
/Users/runner/hostedtoolcache/Ruby/3.4.1/arm64/lib/libruby.3.4.dylib(rb_f_require+0x44) [0x1039c2a3c]
/Users/runner/hostedtoolcache/Ruby/3.4.1/arm64/lib/libruby.3.4.dylib(vm_call_cfunc_with_frame_+0xf0) [0x103b10ce8]
/Users/runner/hostedtoolcache/Ruby/3.4.1/arm64/lib/libruby.3.4.dylib(vm_exec_core+0x2468) [0x103af4cf0]
/Users/runner/hostedtoolcache/Ruby/3.4.1/arm64/lib/libruby.3.4.dylib(rb_vm_exec+0x1e8) [0x103af136c]
/Users/runner/hostedtoolcache/Ruby/3.4.1/arm64/lib/libruby.3.4.dylib(ruby_opt_init+0x138) [0x103a76fb4]
/Users/runner/hostedtoolcache/Ruby/3.4.1/arm64/lib/libruby.3.4.dylib(ruby_process_options+0x1150) [0x103a75a90]
/Users/runner/hostedtoolcache/Ruby/3.4.1/arm64/lib/libruby.3.4.dylib(ruby_options+0x9c) [0x1039621d8]
/Users/runner/work/rice/rice/test/unittest(_Z10embed_rubyv+0x6c) [0x100fe3ba0]
/Users/runner/work/rice/rice/test/unittest(_ZL42fixture__Address_Registration_Guard__setupv) [0x100fec360]
/Users/runner/work/rice/rice/test/unittest(_ZN10Test_Suite3runER11Test_Result) [0x10190adf8]
/Users/runner/work/rice/rice/test/unittest(main) [0x10190b748]

On Window, both MSVC and UCRT64 fails with a stack overflow error much earlier in the intialization. Note there is not traceback, the program just exits. So the below stack traces are taken from a debugger.

MSVC:

	x64-vcruntime140-ruby340.dll!ec_stack_overflow(rb_execution_context_struct * ec, int setup) Line 70	C
 	x64-vcruntime140-ruby340.dll!rb_ec_stack_overflow(rb_execution_context_struct * ec, int crit) Line 96	C
 	[Inline Frame] x64-vcruntime140-ruby340.dll!stack_check(rb_execution_context_struct *) Line 384	C
 	x64-vcruntime140-ruby340.dll!rb_call0(rb_execution_context_struct * ec, unsigned __int64 recv, unsigned __int64 mid, int argc, const unsigned __int64 * argv, call_type call_scope, unsigned __int64 self) Line 553	C
 	[Inline Frame] x64-vcruntime140-ruby340.dll!rb_call(unsigned __int64) Line 873	C
 	x64-vcruntime140-ruby340.dll!rb_funcallv_kw(unsigned __int64 recv, unsigned __int64 mid, int argc, const unsigned __int64 * argv, int kw_splat) Line 1071	C
 	x64-vcruntime140-ruby340.dll!rb_obj_call_init_kw(unsigned __int64 obj, int argc, const unsigned __int64 * argv, int kw_splat) Line 1753	C
 	x64-vcruntime140-ruby340.dll!rb_class_new_instance_kw(int argc, const unsigned __int64 * argv, unsigned __int64 klass, int kw_splat) Line 2194	C
 	x64-vcruntime140-ruby340.dll!rb_exc_new_str(unsigned __int64 etype, unsigned __int64 str) Line 1486	C
 	x64-vcruntime140-ruby340.dll!rb_vm_register_special_exception_str(ruby_special_exceptions sp, unsigned __int64 cls, unsigned __int64 mesg) Line 3058	C
 	x64-vcruntime140-ruby340.dll!Init_eval() Line 2163	C
 	x64-vcruntime140-ruby340.dll!rb_call_inits() Line 37	C
 	x64-vcruntime140-ruby340.dll!ruby_setup() Line 87	C
 	x64-vcruntime140-ruby340.dll!ruby_init() Line 99	C
 	unittest.exe!embed_ruby() Line 15	C++
 	unittest.exe!fixture__Keep_Alive__setup() Line 60	C++
 	unittest.exe!Test_Suite::run(Test_Result & result) Line 61	C++
 	unittest.exe!main(int argc, char * * argv) Line 124	C++
 	[External Code]	

Mingw64 with UCRT64:

rb_ec_stack_overflow vm_insnhelper.c:96
stack_check vm_eval.c:384
stack_check vm_eval.c:379
rb_call0 vm_eval.c:553
rb_call vm_eval.c:873
rb_funcallv_kw vm_eval.c:1070
rb_obj_call_init_kw eval.c:1752
rb_class_new_instance_kw object.c:2191
rb_class_new_instance object.c:2199
rb_exc_new_str error.c:1485
rb_vm_register_special_exception_str vm.c:3057
Init_eval eval.c:2162
rb_call_inits inits.c:36
ruby_setup eval.c:86
<unknown> 0x0000000000000000

It does seem to work on Ubuntu though (not sure why, but see https://github.com/ruby-rice/rice/actions/runs/12534403540/job/35007888594)

Is this a bug or has the recommended way to embed Ruby 3.4 in a C++ program changed?

[cfis (Charlie Savage)]

• Description updated (diff)

[cfis (Charlie Savage)]

• Subject changed from Embed Failure to Embed Ruby 3.4 Failure

[cfis (Charlie Savage)]

• Description updated (diff)

[cfis (Charlie Savage)]

• Description updated (diff)

[cfis (Charlie Savage)]

Any advice on how to proceed? We would like to get Rice, and all the gems that depend on it, working with 3.4. Thanks!

[nobu (Nobuyoshi Nakada)]

I can't reproduce it with a standalone program contains your code as main.

[cfis (Charlie Savage)]

Thanks for looking.

We were able to track down the issue, so I should close this issue.

The problem is starting with Ruby 3.4 if the macro RUBY_INIT_STACK is not included then the Rice unit tests will crash. Looking at that macro:

#define RUBY_INIT_STACK \
    VALUE variable_in_this_stack_frame; \
    ruby_init_stack(&variable_in_this_stack_frame);
/** @} */

void
ruby_init_stack(void *addr)
{
    native_main_thread_stack_top = addr;
}

It looks like that sets a marker in the stack. I am guessing you don't see a crash because you are immediately embedding Ruby so there are no stack frames. Rice, however, first loads it test suite and then loads Ruby. So there are several stack frames before embedding.

Without that marker the Rice unittest executable usually crashes immediately upon embedding (you can see in the link above to the github test job). If it happens to get past embedding then the GC does not work (specifically mark functions defined on rb_data_type_t are not called on some object that are on the stack).

So adding this line of code fixes the problem:

https://github.com/ruby-rice/rice/blob/master/test/embed_ruby.cpp#L10.

Our findings are documented here - https://github.com/ruby-rice/rice/pull/242

I don't believe the requirement to use RUBY_INIT_STACK is documented anywhere. It would be great if there could be (maybe htere is?) official documentation explaining how to correctly embed Ruby.

[alanwu (Alan Wu)]

• Status changed from Open to Closed

I don't believe the requirement to use RUBY_INIT_STACK is documented anywhere.

https://docs.ruby-lang.org/capi/en/master/de/d43/group__embed.html#gafc6055f8f4c68775a8a16a05c7c16e6e

You must call this function before any heap allocation by Ruby implementation. Or GC will break living objects.

The requirement is documented for ruby_init_stack(), just a few lines below the macro. Takes a link hop or looking around to get to, so we should improve the documentation for the macro.

[cfis (Charlie Savage)]

That is helpful.

It would be great if there was official documentation on how to embed Ruby. For example, like Python:

https://docs.python.org/3/extending/embedding.html

That would have saved hours of time over the years of reading source code and tracing through Ruby code to see why embedding is crashing. We have had to change embedding code a few times already:

https://github.com/ruby-rice/rice/commit/bb2ecaf107a0b8226e7c6ef91190aafba9854cda
https://github.com/ruby-rice/rice/commit/79880097e17456156dbf1422518fc07e28f2536e
https://github.com/ruby-rice/rice/commit/bb2ecaf107a0b8226e7c6ef91190aafba9854cda
https://github.com/ruby-rice/rice/commit/923f0f3bf15dd5af2cf1dab6299b0ade540fe58a

Without out official documentation its easy for misinformation to spread. For example the top link on Google when search "embed Ruby" has incorrect code:

https://silverhammermba.github.io/emberb/embed/