add metadata field to proposal proto

proto/cosmos/gov/v1beta2/gov.proto

@@ -49,6 +49,9 @@ message Proposal {
   repeated cosmos.base.v1beta1.Coin total_deposit     = 7 [(gogoproto.nullable) = false];
   google.protobuf.Timestamp         voting_start_time = 8 [(gogoproto.stdtime) = true];
   google.protobuf.Timestamp         voting_end_time   = 9 [(gogoproto.stdtime) = true];
+
+  // metadata is any arbitrary metadata to attached to the proposal.
+  bytes metadata = 10;
 }
 
 // ProposalStatus enumerates the valid statuses of a proposal.

proto/cosmos/gov/v1beta2/tx.proto

@@ -18,8 +18,6 @@ service Msg {
   rpc Vote(MsgVote) returns (MsgVoteResponse);
 
   // VoteWeighted defines a method to add a weighted vote on a specific proposal.
-  //
-  // Since: cosmos-sdk 0.43
   rpc VoteWeighted(MsgVoteWeighted) returns (MsgVoteWeightedResponse);
 
   // Deposit defines a method to add deposit on a specific proposal.
@@ -32,6 +30,8 @@ message MsgSubmitProposal {
   repeated google.protobuf.Any messages             = 1;
   repeated cosmos.base.v1beta1.Coin initial_deposit = 2 [(gogoproto.nullable) = false];
   string                            proposer        = 3 [(cosmos_proto.scalar) = "cosmos.AddressString"];
+  // metadata is any arbitrary metadata to attached to the proposal.
+  bytes metadata = 4;
 }
 
 // MsgSubmitProposalResponse defines the Msg/SubmitProposal response type.
@@ -50,17 +50,13 @@ message MsgVote {
 message MsgVoteResponse {}
 
 // MsgVoteWeighted defines a message to cast a vote.
-//
-// Since: cosmos-sdk 0.43
 message MsgVoteWeighted {
   uint64                      proposal_id = 1;
   string                      voter       = 2 [(cosmos_proto.scalar) = "cosmos.AddressString"];
   repeated WeightedVoteOption options     = 3;
 }
 
 // MsgVoteWeightedResponse defines the Msg/VoteWeighted response type.
-//
-// Since: cosmos-sdk 0.43
 message MsgVoteWeightedResponse {}
 
 // MsgDeposit defines a message to submit a deposit to an existing proposal.

x/gov/keeper/keeper.go

@@ -36,6 +36,9 @@ type Keeper struct {
 
 	// Proposal router
 	router v1beta1.Router
+
+	// maxMetadataLen defines the maximum length of a proposal metadata.
+	maxMetadataLen uint64
 }
 
 // NewKeeper returns a governance keeper. It handles:
@@ -48,6 +51,7 @@ type Keeper struct {
 func NewKeeper(
 	cdc codec.BinaryCodec, key storetypes.StoreKey, paramSpace types.ParamSubspace,
 	authKeeper types.AccountKeeper, bankKeeper types.BankKeeper, sk types.StakingKeeper, rtr v1beta1.Router,
+	maxMetadataLen uint64,
 ) Keeper {
 
 	// ensure governance module account is set
@@ -61,13 +65,14 @@ func NewKeeper(
 	rtr.Seal()
 
 	return Keeper{
-		storeKey:   key,
-		paramSpace: paramSpace,
-		authKeeper: authKeeper,
-		bankKeeper: bankKeeper,
-		sk:         sk,
-		cdc:        cdc,
-		router:     rtr,
+		storeKey:       key,
+		paramSpace:     paramSpace,
+		authKeeper:     authKeeper,
+		bankKeeper:     bankKeeper,
+		sk:             sk,
+		cdc:            cdc,
+		router:         rtr,
+		maxMetadataLen: maxMetadataLen,
 	}
 }