zlib: zstdCompressSync() does not validate pledgedSrcSize

[Archkon]

Version

latest main branch

Platform

7.1.3-arch1-3

Subsystem

zlib

What steps will reproduce the bug?

  const assert = require('node:assert/strict');
  const zlib = require('node:zlib');

  const input = Buffer.alloc(42);

  assert.throws(
    () => zlib.zstdCompressSync(input, {
      pledgedSrcSize: 1,
    }),
    {
      code: 'ZSTD_error_srcSize_wrong',
    },
  );

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

Every Time

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

zstdCompressSync() should throw an error with:

  {
    code: 'ZSTD_error_srcSize_wrong',
    errno: zlib.constants.ZSTD_error_srcSize_wrong,
  }

What do you see instead?

Compression succeeds, causing assert.throws() to fail with

Additional information

The synchronous convenience API processes the input using the default final operation:

ZSTD_e_end

Therefore, its first compression call is effectively:

ZSTD_compressStream2(cctx, output, input, ZSTD_e_end);

Zstd has special behavior for this case. When the first call for a frame uses ZSTD_e_end, it replaces a previously configured pledged source size with the current input size.