New bitfield types in proto (#2915)

* Cast bytes to correct bitfield, failing tests now though

* Add forked gogo/protobuf until gogo/protobuf#582

* remove newline

WORKSPACE

@@ -1102,3 +1102,18 @@ go_repository(
     commit = "29f32d820d112dbd66e58492a6ffb7cc3106312b",
     importpath = "gopkg.in/d4l3k/messagediff.v1",
 )
+
+go_repository(
+    name = "com_github_prysmaticlabs_go_bitfield",
+    commit = "66dcdec9762a9f5935d9466b18f4bee852d1b091",
+    importpath = "github.com/prysmaticlabs/go-bitfield",
+)
+
+go_repository(
+    name = "com_github_gogo_protobuf",
+    commit = "c91f1861c28312f505e13bd3e1c90d2088a670c7",
+    importpath = "github.com/gogo/protobuf",
+    # Using fork until https://github.com/gogo/protobuf/pull/582 is merged.
+    remote = "https://github.com/prestonvanloon/protobuf.git",
+    vcs = "git",
+)

proto/beacon/p2p/v1/BUILD.bazel

@@ -4,13 +4,14 @@ load("@io_bazel_rules_go//proto:def.bzl", "go_proto_library")
 
 go_proto_library(
     name = "v1_go_proto",
+    compiler = "//:proto_compiler",
     importpath = "github.com/prysmaticlabs/prysm/proto/beacon/p2p/v1",
     proto = ":v1_proto",
     visibility = ["//visibility:public"],
     deps = [
         "//proto/common:common_go_proto",
+        "@com_github_prysmaticlabs_go_bitfield//:go_default_library",
     ],
-    compiler = "//:proto_compiler",
 )
 
 go_library(
@@ -28,8 +29,8 @@ proto_library(
     ],
     visibility = ["//visibility:public"],
     deps = [
+        "//proto/common:common_proto",
         "@com_google_protobuf//:timestamp_proto",
         "@gogo_special_proto//github.com/gogo/protobuf/gogoproto",
-        "//proto/common:common_proto",
     ],
 )

proto/beacon/p2p/v1/types.proto

@@ -44,8 +44,8 @@ message BeaconState {
   repeated Crosslink current_crosslinks = 8002 [(gogoproto.moretags) = "ssz-size:\"1024\""];
 
   // Finality [9001-10000]
-  // Spec type [4]Bitvector which means this would be a fixed size of 1 byte.
-  bytes justification_bits = 9001 [(gogoproto.moretags) = "ssz-size:\"1\""];
+  // Spec type [4]Bitvector which means this would be a fixed size of 4 bits.
+  bytes justification_bits = 9001 [(gogoproto.casttype) = "github.com/prysmaticlabs/go-bitfield.Bitvector4"];
   Checkpoint previous_justified_checkpoint = 9002;
   Checkpoint current_justified_checkpoint = 9003;
   Checkpoint finalized_checkpoint = 9004;
@@ -60,7 +60,7 @@ message Fork {
 message PendingAttestation {
   // Bitfield representation of validator indices that have voted exactly
   // the same vote and have been aggregated into this attestation.
-  bytes aggregation_bits = 1 [(gogoproto.moretags) = "ssz-max:\"4096\""];
+  bytes aggregation_bits = 1 [(gogoproto.moretags) = "ssz-max:\"4096\"", (gogoproto.casttype) = "github.com/prysmaticlabs/go-bitfield.Bitlist"];
   AttestationData data = 2;
   // The difference of when attestation gets created and get included on chain.
   uint64 inclusion_delay = 3;
@@ -73,7 +73,7 @@ message Attestation {
   // Bitfield representation of validator indices that have voted exactly
   // the same vote and have been aggregated into this attestation.
   // Spec type: Bitlist[4096]
-  bytes aggregation_bits = 2 [(gogoproto.moretags) = "ssz-max:\"4096\""];
+  bytes aggregation_bits = 2 [(gogoproto.moretags) = "ssz-max:\"4096\"", (gogoproto.casttype) = "github.com/prysmaticlabs/go-bitfield.Bitlist"];
   // Challengeable bit (SSZ-bool, 1 byte) for the custody of crosslink data. Not used in phase 0.
   bytes custody_bits = 3 [(gogoproto.moretags) = "ssz-max:\"4096\""];
   // 96 byte BLS aggregate signature.
@@ -211,7 +211,7 @@ message BeaconBlockBody {
 
 message SlashableAttestation {
   repeated uint64 validator_indices = 1;
-  bytes custody_bits = 2 [(gogoproto.moretags) = "ssz-size:\"4096\""];
+  bytes custody_bits = 2 [(gogoproto.moretags) = "ssz-size:\"4096\"", (gogoproto.casttype) = "github.com/prysmaticlabs/go-bitfield.Bitlist"];;
   AttestationData data = 3;
   bytes signature = 4 [(gogoproto.moretags) = "ssz-size:\"96\""];
 }