ini_write_string silently writes empty string for non-string values

[qum1nzhennan]

Summary

ini_write_string() silently persists an empty string whenever the third argument is not already an RVALUE_STRING. Native GameMaker converts any value to a string, so GML like ini_write_string("S", "K", 123) must persist K="123", but Butterscotch writes K="".

Environment

• Butterscotch built from main (relevant code: src/vm_builtins.c)
• Android frontend
• Game: DELTARUNE (GMS 2.3 / WAD 17 bytecode) with the gm3dr/DeltaruneChinese community patch installed

Root cause

src/vm_builtins.c, builtin_ini_write_string:

const char* value = (args[2].type == RVALUE_STRING ? args[2].string : "");

Any non-string third argument is silently discarded and replaced with "". The adjacent builtin_ini_write_real already does the right thing:

char* valueStr = RValue_toString(args[2]);

Minimal repro

ini_open("test.ini");
ini_write_string("TEST", "VALUE", 123);
ini_close();

Resulting file on disk (wrong):

[TEST]
VALUE=""

Native GameMaker writes VALUE="123".

Real-world failure this caused

Deltarune's Chinese localization patch implements the in-game name translation toggle like this:

function scr_change_language() {
    global.names = (global.names + 1) % 3;              // number: 0/1/2
    ossafe_ini_open("true_config.ini");
    ini_write_string("L10N_ZH", "NAMES", global.names); // numeric value
    ossafe_ini_close();
    ossafe_savedata_save();
    scr_84_init_localization(); // immediately reads ini_read_real("L10N_ZH", "NAMES", 0)
}

Instrumentation confirmed the whole chain fires on Android: virtual Z key down -> keyboard_check(90)=true -> input_pressed[4]=1 -> button1_p()=1 -> scr_change_language() runs, and true_config.ini is rewritten at that exact moment - but with:

[L10N_ZH]
NAMES=""

scr_84_init_localization() then reads "" back as real 0, so the toggle instantly reverts and the option appears to do nothing.

Suggested fix

static RValue builtin_ini_write_string(VMContext* ctx, RValue* args, int32_t argCount) {
    Runner* runner = ctx->runner;
    if (3 > argCount || runner->currentIni == nullptr) return RValue_makeUndefined();

    const char* section = (args[0].type == RVALUE_STRING ? args[0].string : "");
    const char* key = (args[1].type == RVALUE_STRING ? args[1].string : "");
    char* value = RValue_toString(args[2]);

    Ini_setString(runner->currentIni, section, key, value);
    runner->currentIniDirty = true;
    free(value);
    return RValue_makeUndefined();
}

Happy to open a PR with this fix if that helps.