Fix three VM memory leaks: computed-property double creation, missing frees in gravity_core_free, orphaned GC gray-list buffer

[barchett]

Found while running an embedding host (repeated compile/run/free cycles) under AddressSanitizer/LeakSanitizer. Three distinct leaks, all reproducible with a minimal embed loop (below):

1. Computed properties created twice in gravity_core_init (double macro expansion)

When GRAVITY_USE_HIDDEN_INITIALIZERS is not set, VALUE_FROM_OBJECT() evaluates its argument twice:

#define VALUE_FROM_OBJECT(obj) ((gravity_value_t){.isa = ((gravity_object_t *)(obj)->isa), .p = (gravity_object_t *)(obj)})

Six bind sites in gravity_core_init call computed_property_create() inline inside that macro (Object.class, Object.meta, Int meta min/max, Float meta min/max). Each of those computed properties is therefore created twice — one copy gets bound, the duplicate is orphaned immediately (~2.2KB leaked per gravity_core_init, even without ever freeing the core). The fix uses the same temp-variable pattern the rest of gravity_core_init already uses for every other computed property, plus a comment warning against calling computed_property_create inline inside the macro.

2. Nine computed properties missing from gravity_core_free's manual free list

gravity_core_free manually frees List.count, Map.count, Range.count, String.length, Int/Float.radians/degrees, and System.gcEnabled — but not Object.class, Object.meta, Range.from, Range.to, String.bytes, Int meta min/max, or Float meta min/max, which gravity_core_init also creates. Each core init/free cycle leaked these (~3.3KB per cycle for hosts that restart the script engine).

3. GC gray-list buffer orphaned in gravity_vm_new

gravity_vm_new calls gravity_gc_setenabled(vm, true) before marray_init(vm->graylist). Enabling the GC can trigger a collection (gravity_gc_check → gravity_gc_start), which grows the gray-list buffer via marray_push/realloc — and the marray_init that follows zeroes the array struct, orphaning that buffer (one buffer leaked per VM). Fixed by initializing graylist/gctemp before enabling the GC.

Repro

for (int i = 0; i < 3; ++i) {
    gravity_delegate_t delegate = { .error_callback = report_error };
    gravity_compiler_t *compiler = gravity_compiler_create(&delegate);
    gravity_closure_t *closure = gravity_compiler_run(compiler, source, strlen(source), 0, true, true);
    gravity_vm *vm = gravity_vm_new(&delegate);
    gravity_compiler_transfer(compiler, vm);
    gravity_compiler_free(compiler);
    if (closure) { gravity_vm_runmain(vm, closure); gravity_gc_start(vm); }
    gravity_vm_free(vm);
    gravity_core_free();
}

Built with -fsanitize=address: before — SUMMARY: AddressSanitizer: 22296 byte(s) leaked in 156 allocation(s); after — clean exit, zero leaks.

Testing

• make && test/unittest/run_all.sh: 350/350 pass, 0 failed, 0 timed out with the patches applied.
• The ASan embed loop above runs leak-free.

🤖 Generated with Claude Code

[vercel]

@barchett is attempting to deploy a commit to the sqlitecloud Team on Vercel.

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[marcobambini]

Thanks @barchett