deno ffi issue repro

Dockerfile

FROM denoland/deno:alpine-1.44.3

WORKDIR /app

RUN apk add pcre2

USER deno

COPY . /app

CMD ["run", "-A", "--unstable-ffi", "main.ts"]

main.ts

const library = Deno.dlopen('/usr/lib/libpcre2-8.so.0', {
    pcre2_compile_8: {
        parameters: ['buffer', 'usize', 'u32', 'pointer', 'pointer', 'pointer'],
        result: 'pointer',
    },
    pcre2_substitute_8: {
        parameters: [
            'pointer',
            'buffer',
            'u32',
            'u32',
            'u32',
            'pointer',
            'pointer',
            'buffer',
            'u32',
            'buffer',
            'pointer',
        ],
        result: 'i32',
    },
} as const)

const PCRE2_UTF = 0x00080000
const PCRE2_SUBSTITUTE_EXTENDED = 0x00000200
const PCRE2_SUBSTITUTE_OVERFLOW_LENGTH = 0x00001000

const lastErr = new Uint32Array(1)
const lastErrPtr = Deno.UnsafePointer.of(lastErr)
const lastErrOffset = new Uint32Array(1)
const lastErrOffsetPtr = Deno.UnsafePointer.of(lastErrOffset)
const outLen = new Uint32Array(1)
const outLenPtr = Deno.UnsafePointer.of(outLen)

export function compile(pattern: string): Deno.PointerValue {
    const patternBuf = new TextEncoder().encode(pattern)

    const code = library.symbols.pcre2_compile_8(
        patternBuf,
        BigInt(patternBuf.byteLength),
        PCRE2_UTF,
        lastErrPtr,
        lastErrOffsetPtr,
        null,
    )

    if (!code) {
        throw new Error(
            `pcre2_compile_8 error: ${lastErr[0]}`,
        )
    }

    return code
}

export function substitute(
    code: Deno.PointerValue,
    subject: string,
    replacement: string,
    global = false,
): string {
    const subjectBuf = new TextEncoder().encode(subject)
    const replacementBuf = new TextEncoder().encode(replacement)

    let resultBuf = new Uint8Array(1024)

    const flags =
        PCRE2_SUBSTITUTE_EXTENDED |
        PCRE2_SUBSTITUTE_OVERFLOW_LENGTH

    outLen[0] = resultBuf.byteLength
    let res = library.symbols.pcre2_substitute_8(
        code,
        subjectBuf,
        subjectBuf.byteLength,
        0,
        flags,
        null,
        null,
        replacementBuf,
        replacementBuf.byteLength,
        resultBuf,
        outLenPtr,
    )

    if (res < 0) {
        throw new Error(`pcre2_substitute_8 error: ${res}`)
    }

    return new TextDecoder().decode(resultBuf.slice(0, outLen[0]))
}

const re = compile('hello')

console.log(substitute(re, 'hello world', 'goodbye'))