fix(ext/node): omit smi from zlib.crc32 op function

[Tango992]

Closes #30636

[Tango992]

Maybe I'm missing something, but sometimes value that's being passed to the op as smi can be interpreted differently.

Try modify this function by adding a print statement: println!("op_zlib_crc32 called with checksum: {:#x}", value);

deno/ext/node/ops/zlib/mod.rs

Lines 925 to 931 in 415acdd

	#[op2(fast)]
	pub fn op_zlib_crc32_string(#[string] data: &str, #[smi] value: u32) -> u32 {
	// SAFETY: `data` is a valid buffer.
	unsafe {
	zlib::crc32(value as c_ulong, data.as_ptr(), data.len() as u32) as u32
	}
	}

import { crc32 } from "node:zlib";

let checkSum = 0xffffffff;
for (let i = 0; i < 2**16; i++) {
  const currentChecksum = crc32("", checkSum);
  if (currentChecksum !== checkSum) {
    console.error("iteration", i, `failed with checksum: 0x${currentChecksum.toString(16)}`);
    process.exit(1);
  }
}

console.log(`Final CRC32: 0x${checkSum.toString(16)}`);

Here's the output:

...
op_zlib_crc32 called with checksum: 0xffffffff
op_zlib_crc32 called with checksum: 0xffffffff
op_zlib_crc32 called with checksum: 0xffffffff
op_zlib_crc32 called with checksum: 0xffffffff
op_zlib_crc32 called with checksum: 0xffffffff
op_zlib_crc32 called with checksum: 0xffffffff
op_zlib_crc32 called with checksum: 0xffffffff
op_zlib_crc32 called with checksum: 0x7fffffff
iteration 6216 failed with checksum: 0x7fffffff

Somehow the op function sees the value as 2**31 - 1. It happens randomly, and what causes the original issue at the first place.

[nathanwhit]

The reason for that behavior is that it depends on whether or not V8 chooses to make a fast call or not. The smi optimization, as far as i know, only applies for fast calls. So when V8 doesn't take the fast call, you get the correct integer value, but the fast calls get the maximum value for a smi which is 2**31 - 1

Typically V8 will only choose fast calls once you've called the function a large number of times, especially in a hot loop. So it makes sense that this would occur only after a few thousand calls

[nathanwhit]

LGTM