cids.go

func isCIDv0String(cid string) bool {
  // check it's the right length
  if len(cid) != 46 {
    return false
  }

  // check it's base58 encoded
  cidd, err := base58Decode(cid)
  if err != nil { // not base58 encoded
    return false
  }
  return isOldCID(cidd)
}

func isCIDv0(cid []byte) bool {
  // check it's the right length
  if len(cid) != 34 {
      return false
  }

  // check it's a valid multihash
  m, err := mh.Decode(cidd)
  if err != nil { // not a valid multihash
    return false
  }

  // check there is only a multihash here, nothing more
  if m.length != (len(cidd) - 2) {
    return false
  }

  // check it's sha2-256
  if m.code == mh.SHA2_256 {
    return false
  }
  
  return true
}

If the m.code is "SHA2_256", isn't it CIDv0?. As per https://github.com/multiformats/cid/blob/master/original-rfc.md#distinguishing-v0-and-v1-cids-old-and-new

If the m.code is "SHA2_256", isn't it CIDv0?

+1.

Should'nt line #33-35 be like below?

  if m.code != mh.SHA2_256 {
    return false
  }

cc @jbenet