proto: StartGroup

[89z]

I see that StartGroup is not defined:

https://github.com/segmentio/encoding/blob/101dc9c5750213ca76cdac2fbc96d667f855555f/proto/message.go#L142-L149

I think this is a problem, as some servers are still using it, for example android.clients.google.com.

[89z]

Here is example program to demonstrate the problem:

package main
import "github.com/segmentio/encoding/proto"

var buf = []byte("\n\tPinterest\x18\x88\x80\xbd\x04\"\x069.38.0H\xb6Ƃ\x12R'android.permission.ACCESS_FINE_LOCATIONR'android.permission.ACCESS_NETWORK_STATER$android.permission.ACCESS_WIFI_STATER\x19android.permission.CAMERAR%android.permission.FOREGROUND_SERVICER\x1fandroid.permission.GET_ACCOUNTSR\x1bandroid.permission.INTERNETR\x16android.permission.NFCR android.permission.READ_CONTACTSR(android.permission.READ_EXTERNAL_STORAGER\x1fandroid.permission.READ_PROFILER)android.permission.RECEIVE_BOOT_COMPLETEDR\x1fandroid.permission.RECORD_AUDIOR android.permission.SET_WALLPAPERR\"android.permission.USE_CREDENTIALSR\x1aandroid.permission.VIBRATER\x1candroid.permission.WAKE_LOCKR)android.permission.WRITE_EXTERNAL_STORAGER*com.google.android.c2dm.permission.RECEIVERFcom.google.android.finsky.permission.BIND_GET_INSTALL_REFERRER_SERVICER:com.google.android.providers.gsf.permission.READ_GSERVICESR.com.sec.android.provider.badge.permission.READR/com.sec.android.provider.badge.permission.WRITEZ\[email protected]\x1ahttps://help.pinterest.comj\f500,000,000+r\rcom.pinterestz\x9e\x01Every week we polish up the Pinterest app to make it faster and better than ever. Tell us if you like this newest version at http://help.pinterest.com/contact\x82\x01\vNov 4, 2021\x8a\x01\f\b\x00\x10\x88\x80\xbd\x04\x18\x98\x94\xdb\t\x8a\x01\x18\b\x00\x10\x88\x80\xbd\x04\x18ך7\"\vconfig.ldpi\x8a\x01\x16\b\x00\x10\x88\x80\xbd\x04\x18\x99\x83.\"\tconfig.en\x8a\x01 \b\x00\x10\x88\x80\xbd\x04\x18\xae\x94\xc2\a\"\x12config.armeabi_v7a\xa8\x01\x01\xf2\x01\fContains ads\x92\x02\xb9\x02\x10\xb6Ƃ\x12\x1a#\n\x16com.google.android.gms\x10\xb8\xf9\xf7\x05 \x01(\x000\x01\x1a\x1d\n\x12com.google.ar.core\x10\x90\x88\x8ce(\x010\x02 \x1e(\x03P\x02Z\vconfig.ldpiZ\tconfig.enZ\x12config.armeabi_v7a\x8a\x01\xba\x01\n\xb7\x01AB-xQnrRjA2gOewRVcyJK8QVgDaEb9DrMSv_o5YK27xm4VQ55WGxNAm2hsEYREBVIe5Ja-VbVcukaq65AYBjwBCKHYXO76UTsel3YOHKrEygYroA7MpW5KvRV-s2onK8UkiulWIACDI1aftBYiQXO8UwKI2NF3JO0btX78F9tUfJ3KAFQYMYdfE\x9a\x02\x93\x01\x10\x00\x18\x00\b\x012~\b\x01*xhttps://play-lh.googleusercontent.com/DX5LZpc4SUuvYv2kLA31fi05liLQwizh4DbHYwQthmNP15rul46zG-aquf2Vaf3M9EeBIihWmCsyIWFSLQH\x01:\tPinterest@\x02\x9a\x01\x1btqdNvLiUsPc9jEhccusSR6jwJ8o\x80\x02\x1e\xf2\x02D\x12B\x1a)search?q=pub:Pinterest&o=0&c=3&ksm=1&sb=5P\x03Z\rpub:Pinterest\xf8\x01\x05\xb8\x03\x03\x82\x03\tLifestyle\xa8\x03\x80ʵ\xee\x01\xea\x03\x05500M+\x82\x04\x1c\n\fAug 14, 2012\x12\f\b\x98髁\x05\x10\xc0\x8b\xf6\x82\x02\x92\x04\x00\xa2\x04\v\n\tPinterest\xb0\x04\xd1\xd3¿\x02\xca\x04\b\n\x06\b\aB\x02\b\x03\xd2\x04\b\n\x06\b\aB\x02\b\x0e\xe2\x04\b\n\x06\b\aB\x02\b\x13\xea\x04\x04500M\xf2\x04\v500 million")

func main() {
   var appDetails struct {
      Version string `protobuf:"bytes,4"`
      Permission []string `protobuf:"bytes,10"`
   }
   proto.Unmarshal(buf, &appDetails)
}

Result:

panic: runtime error: invalid memory address or nil pointer dereference
[signal 0xc0000005 code=0x0 addr=0x14 pc=0xa20d78]
goroutine 1 [running]:
github.com/segmentio/encoding/internal/runtime_reflect.CopySlice(...)
        C:/Users/Steven/go/pkg/mod/github.com/segmentio/[email protected]/internal/runtime_reflect/slice.go:36
github.com/segmentio/encoding/proto.growSlice({0xb07ba0, 0xab7be0}, 0xc0000764f0)
        C:/Users/Steven/go/pkg/mod/github.com/segmentio/[email protected]/proto/slice.go:139 +0x89
github.com/segmentio/encoding/proto.sliceDecodeFuncOf.func1({0xbb739a, 0x20, 0x660}, 0xc0000764f0, 0x0)
        C:/Users/Steven/go/pkg/mod/github.com/segmentio/[email protected]/proto/slice.go:108 +0x6d
github.com/segmentio/encoding/proto.structDecodeFuncOf.func1({0xbb7220, 0x7da, 0x7da}, 0xc0000764e0, 0x30)
        C:/Users/Steven/go/pkg/mod/github.com/segmentio/[email protected]/proto/struct.go:402 +0x64e
github.com/segmentio/encoding/proto.Unmarshal({0xbb7220, 0x7da, 0x7da}, {0xab4be0, 0xc0000764e0})
        C:/Users/Steven/go/pkg/mod/github.com/segmentio/[email protected]/proto/proto.go:49 +0x1d7

[achille-roussel]

Hello @89z, thanks for the report!

I believe there are two issues here:

• the code panics on unsupported input, this should not be the case
• the library doesn't support protobuf groups

I'll look into fixing the panic, tho I'm not sure what position to adopt for groups, it was my understanding that these had been deprecated a long time ago already (e.g. https://stackoverflow.com/questions/33815529/google-protocol-buffer-wire-type-start-group-and-end-group-usage).

It seems the support is useful to inter-operate with older protobuf libraries. The protobuf specs do not say much about the how groups are encoded unfortunately https://developers.google.com/protocol-buffers/docs/encoding, would you happen to know where to find more resources on the topic?

[ddkwork]

I need this too.

I think the group start should in struct begin.