Streamline Stargate/gRPC querier interfaces (#2093)

* Change RejectStargateQuerier from factory function to free function

* Clarify error message to help contract developers

* Streamline and improve documentation for RejectGrpcQuerier

* Pull out function signatures

* [autofix.ci] apply automated fixes

---------

Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>

Author: webmaster128

x/wasm/keeper/query_plugins.go

@@ -84,13 +84,18 @@ func (q QueryHandler) GasConsumed() uint64 {
 
 type CustomQuerier func(ctx sdk.Context, request json.RawMessage) ([]byte, error)
 
+type (
+	stargateQuerierFn func(ctx sdk.Context, request *wasmvmtypes.StargateQuery) ([]byte, error)
+	grpcQuerierFn     func(ctx sdk.Context, request *wasmvmtypes.GrpcQuery) (proto.Message, error)
+)
+
 type QueryPlugins struct {
 	Bank         func(ctx sdk.Context, request *wasmvmtypes.BankQuery) ([]byte, error)
 	Custom       CustomQuerier
 	IBC          func(ctx sdk.Context, caller sdk.AccAddress, request *wasmvmtypes.IBCQuery) ([]byte, error)
 	Staking      func(ctx sdk.Context, request *wasmvmtypes.StakingQuery) ([]byte, error)
-	Stargate     func(ctx sdk.Context, request *wasmvmtypes.StargateQuery) ([]byte, error)
-	Grpc         func(ctx sdk.Context, request *wasmvmtypes.GrpcQuery) (proto.Message, error)
+	Stargate     stargateQuerierFn
+	Grpc         grpcQuerierFn
 	Wasm         func(ctx sdk.Context, request *wasmvmtypes.WasmQuery) ([]byte, error)
 	Distribution func(ctx sdk.Context, request *wasmvmtypes.DistributionQuery) ([]byte, error)
 }
@@ -121,7 +126,7 @@ func DefaultQueryPlugins(
 		Custom:       NoCustomQuerier,
 		IBC:          IBCQuerier(wasm, channelKeeper),
 		Staking:      StakingQuerier(staking, distKeeper),
-		Stargate:     RejectStargateQuerier(),
+		Stargate:     RejectStargateQuerier,
 		Grpc:         RejectGrpcQuerier,
 		Wasm:         WasmQuerier(wasm),
 		Distribution: DistributionQuerier(distKeeper),
@@ -332,10 +337,15 @@ func IBCQuerier(wasm contractMetaDataSource, channelKeeper types.ChannelKeeper)
 	}
 }
 
+// RejectGrpcQuerier is a querier that rejects all gRPC queries.
+//
+// Use AcceptListGrpcQuerier instead to create a list of accepted query types.
 func RejectGrpcQuerier(ctx sdk.Context, request *wasmvmtypes.GrpcQuery) (proto.Message, error) {
-	return nil, wasmvmtypes.UnsupportedRequest{Kind: "gRPC queries are disabled"}
+	return nil, wasmvmtypes.UnsupportedRequest{Kind: "gRPC queries are disabled on this chain"}
 }
 
+var _ grpcQuerierFn = RejectGrpcQuerier // just a type check
+
 // AcceptListGrpcQuerier supports a preconfigured set of gRPC queries only.
 // All arguments must be non nil.
 //
@@ -344,7 +354,7 @@ func RejectGrpcQuerier(ctx sdk.Context, request *wasmvmtypes.GrpcQuery) (proto.M
 //
 // These queries can be set via WithQueryPlugins option in the wasm keeper constructor:
 // WithQueryPlugins(&QueryPlugins{Grpc: AcceptListGrpcQuerier(acceptList, queryRouter, codec)})
-func AcceptListGrpcQuerier(acceptList AcceptedQueries, queryRouter GRPCQueryRouter, codec codec.Codec) func(ctx sdk.Context, request *wasmvmtypes.GrpcQuery) (proto.Message, error) {
+func AcceptListGrpcQuerier(acceptList AcceptedQueries, queryRouter GRPCQueryRouter, codec codec.Codec) grpcQuerierFn {
 	return func(ctx sdk.Context, request *wasmvmtypes.GrpcQuery) (proto.Message, error) {
 		protoResponseFn, accepted := acceptList[request.Path]
 		if !accepted {
@@ -375,13 +385,15 @@ func AcceptListGrpcQuerier(acceptList AcceptedQueries, queryRouter GRPCQueryRout
 	}
 }
 
-// RejectStargateQuerier rejects all stargate queries
-func RejectStargateQuerier() func(ctx sdk.Context, request *wasmvmtypes.StargateQuery) ([]byte, error) {
-	return func(ctx sdk.Context, request *wasmvmtypes.StargateQuery) ([]byte, error) {
-		return nil, wasmvmtypes.UnsupportedRequest{Kind: "Stargate queries are disabled"}
-	}
+// RejectStargateQuerier is a querier that rejects all stargate queries.
+//
+// Use AcceptListStargateQuerier instead to create a list of accepted query types.
+func RejectStargateQuerier(ctx sdk.Context, request *wasmvmtypes.StargateQuery) ([]byte, error) {
+	return nil, wasmvmtypes.UnsupportedRequest{Kind: "Stargate queries are disabled on this chain"}
 }
 
+var _ stargateQuerierFn = RejectStargateQuerier // just a type check
+
 // AcceptedQueries defines accepted Stargate or gRPC queries as a map where the key is the query path
 // and the value is a function returning a proto.Message.
 //
@@ -400,7 +412,7 @@ type AcceptedQueries map[string]func() proto.Message
 //
 // These queries can be set via WithQueryPlugins option in the wasm keeper constructor:
 // WithQueryPlugins(&QueryPlugins{Stargate: AcceptListStargateQuerier(acceptList, queryRouter, codec)})
-func AcceptListStargateQuerier(acceptList AcceptedQueries, queryRouter GRPCQueryRouter, codec codec.Codec) func(ctx sdk.Context, request *wasmvmtypes.StargateQuery) ([]byte, error) {
+func AcceptListStargateQuerier(acceptList AcceptedQueries, queryRouter GRPCQueryRouter, codec codec.Codec) stargateQuerierFn {
 	return func(ctx sdk.Context, request *wasmvmtypes.StargateQuery) ([]byte, error) {
 		protoResponseFn, accepted := acceptList[request.Path]
 		if !accepted {