_FieldSkipper problem

[vadimkantorov]

I am trying to parse a Caffe model. I am getting an error related to _FieldSkipper:

/sequoia/data2/kantorov/wigwam_sequoia_gpu101_105/.wigwam/prefix/bin/luajit: ...01_105/.wigwam/prefix/share/lua/5.1/protobuf/decoder.lua:333: attempt to call a nil value
stack traceback:
    ...01_105/.wigwam/prefix/share/lua/5.1/protobuf/decoder.lua:333: in function 'SkipField'
    ...pu101_105/.wigwam/prefix/share/lua/5.1/protobuf/init.lua:672: in function '_InternalParse'
    ...01_105/.wigwam/prefix/share/lua/5.1/protobuf/decoder.lua:248: in function 'field_decoder'
    ...pu101_105/.wigwam/prefix/share/lua/5.1/protobuf/init.lua:678: in function '_InternalParse'
    ...01_105/.wigwam/prefix/share/lua/5.1/protobuf/decoder.lua:248: in function 'field_decoder'
    ...pu101_105/.wigwam/prefix/share/lua/5.1/protobuf/init.lua:678: in function '_internal_parse'
    ...pu101_105/.wigwam/prefix/share/lua/5.1/protobuf/init.lua:687: in function 'merge_from_string'
    ...pu101_105/.wigwam/prefix/share/lua/5.1/protobuf/init.lua:696: in function 'ParseFromString'
    test.lua:5: in main chunk
    [C]: in function 'dofile'
    ...105/.wigwam/prefix/lib/luarocks/rocks/trepl/scm-1/bin/th:145: in main chunk
    [C]: at 0x00410a40

Putting this code snippet here for convenience:

function _FieldSkipper()
  WIRETYPE_TO_SKIPPER = {
    _SkipVarint,
    _SkipFixed64,
    _SkipLengthDelimited,
    _SkipGroup,
    _EndGroup,
    _SkipFixed32,
    _RaiseInvalidWireType,
    _RaiseInvalidWireType,
  }

  --wiretype_mask = wire_format.TAG_TYPE_MASK
  local ord = string.byte
  local sub = string.sub

  return function (buffer, pos, pend, tag_bytes)
    local wire_type = ord(sub(tag_bytes, 1, 1)) % 8 + 1
    --print(wire_type, WIRETYPE_TO_SKIPPER[wire_type])
    return WIRETYPE_TO_SKIPPER[wire_type](buffer, pos, pend) --fails here
  end
end

I added the print line. It prints: 5 nil.

[ijc]

I tripped over this today, it's because _SkipGroup and _EndGroup aren't actually defined (and hence are nil). Probably relates to the fact that https://developers.google.com/protocol-buffers/docs/encoding describes wire types 3 and 4 as deprecated.