ffi: buffer/arraybuffer args reject BigInt pointers in multi-argument fast signatures

[trivikr]

Version

main

Platform

Linux

Subsystem

ffi

What steps will reproduce the bug?

repro.c

#include <stdint.h>

uint64_t ptr_one(void *p) { return (uint64_t)(uintptr_t)p; }
uint64_t ptr_two(void *p, uint64_t extra) { return (uint64_t)(uintptr_t)p + extra; }

Compile it with

$ cc -shared -fPIC -o repro.so repro.c

repro.js

import { dlopen } from 'node:ffi';

const { lib, functions } = dlopen(new URL('repro.so', import.meta.url).pathname, {
  ptr_one: { arguments: ['buffer'], return: 'u64' },
  ptr_two: { arguments: ['buffer', 'u64'], return: 'u64' },
});

for (const [label, call] of [
  ['1-arg buffer(10n)    ', () => functions.ptr_one(10n)],
  ['2-arg buffer(10n, 0n)', () => functions.ptr_two(10n, 0n)],
]) {
  try {
    console.log(label, '->', call());
  } catch (err) {
    console.log(label, '-> THREW', err.code, '-', err.message);
  }
}

lib.close();

How often does it reproduce? Is there a required condition?

Always

What is the expected behavior? Why is that the expected behavior?

1-arg buffer(10n)     -> 10n
2-arg buffer(10n, 0n) -> 10n

Expected both to return 10n, matching the SB/libffi paths which accept BigInt pointers at every arity; if rejection were intended it should be ERR_INVALID_ARG_VALUE with an Argument N prefix like the rest of the module.

What do you see instead?

1-arg buffer(10n)     -> 10n
2-arg buffer(10n, 0n) -> THREW ERR_INVALID_ARG_TYPE - The first argument must be a Buffer, ArrayBuffer, or ArrayBufferView

The one-argument signature returns 10n while the identical buffer type in a two-argument signature throws ERR_INVALID_ARG_TYPE.

Additional information

No response

[trivikr]

Proposed fix in #64964