fix(x/tx)!: unexpected cast of interface to concrete type in GetSignersContext (#15581)

x/tx/CHANGELOG.md

@@ -29,15 +29,22 @@ Ref: https://keepachangelog.com/en/1.0.0/
 
 # Changelog
 
-## [Unreleased]
+## Unreleased
 
-## API Breaking
+### API Breaking
+
+* [#15581](https://github.com/cosmos/cosmos-sdk/pull/15581) `GetSignersOptions` and `directaux.SignModeHandlerOptions` now
+require a `signing.ProtoFileResolver` interface instead of `protodesc.Resolver`.
+
+## v0.4.0
+
+### API Breaking
 
 * [#13793](https://github.com/cosmos/cosmos-sdk/pull/13793) `direct_aux.NewSignModeHandler` constructor function now returns an additional error argument.
 * [#15278](https://github.com/cosmos/cosmos-sdk/pull/15278) Move `x/tx/{textual,aminojson}` into `x/tx/signing`.
 * [#15302](https://github.com/cosmos/cosmos-sdk/pull/15302) `textual.NewSignModeHandler` now takes an options struct instead of a simple coin querier argument. It also returns an error.
 
-## Improvements
+### Improvements
 
 * [#15302](https://github.com/cosmos/cosmos-sdk/pull/15302) Add support for a custom registry (e.g. gogo's MergedRegistry) to be plugged into SIGN_MODE_TEXTUAL.
 * [#15557](https://github.com/cosmos/cosmos-sdk/pull/15557) Implement unknown field filtering.

x/tx/signing/direct_aux/direct_aux.go

@@ -6,25 +6,25 @@ import (
 
 	"github.com/cosmos/cosmos-proto/anyutil"
 	"google.golang.org/protobuf/proto"
-	"google.golang.org/protobuf/reflect/protodesc"
 	"google.golang.org/protobuf/reflect/protoregistry"
 
 	signingv1beta1 "cosmossdk.io/api/cosmos/tx/signing/v1beta1"
 	txv1beta1 "cosmossdk.io/api/cosmos/tx/v1beta1"
+
 	"cosmossdk.io/x/tx/signing"
 )
 
 // SignModeHandler is the SIGN_MODE_DIRECT_AUX implementation of signing.SignModeHandler.
 type SignModeHandler struct {
 	signersContext *signing.GetSignersContext
-	fileResolver   protodesc.Resolver
+	fileResolver   signing.ProtoFileResolver
 	typeResolver   protoregistry.MessageTypeResolver
 }
 
 // SignModeHandlerOptions are the options for the SignModeHandler.
 type SignModeHandlerOptions struct {
 	// FileResolver is the protodesc.Resolver to use for resolving proto files when unpacking any messages.
-	FileResolver protodesc.Resolver
+	FileResolver signing.ProtoFileResolver
 
 	// TypeResolver is the protoregistry.MessageTypeResolver to use for resolving proto types when unpacking any messages.
 	TypeResolver protoregistry.MessageTypeResolver

x/tx/signing/get_signers.go

@@ -17,7 +17,7 @@ import (
 // message where signers are specified by the cosmos.msg.v1.signer protobuf
 // option.
 type GetSignersContext struct {
-	protoFiles      protodesc.Resolver
+	protoFiles      ProtoFileResolver
 	getSignersFuncs map[protoreflect.FullName]getSignersFunc
 }
 
@@ -25,7 +25,14 @@ type GetSignersContext struct {
 type GetSignersOptions struct {
 	// ProtoFiles are the protobuf files to use for resolving message descriptors.
 	// If it is nil, the global protobuf registry will be used.
-	ProtoFiles protodesc.Resolver
+	ProtoFiles ProtoFileResolver
+}
+
+// ProtoFileResolver is a protodesc.Resolver that also allows iterating over all
+// files descriptors. It is a subset of the methods supported by protoregistry.Files.
+type ProtoFileResolver interface {
+	protodesc.Resolver
+	RangeFiles(func(protoreflect.FileDescriptor) bool)
 }
 
 // NewGetSignersContext creates a new GetSignersContext using the provided options.
@@ -60,13 +67,8 @@ func getSignersFieldNames(descriptor protoreflect.MessageDescriptor) ([]string,
 // - it will pre-populate the context's internal cache for getSignersFuncs
 // so that calling it in antehandlers will be faster.
 func (c *GetSignersContext) init() error {
-	fs, ok := c.protoFiles.(*protoregistry.Files)
-	if !ok {
-		return fmt.Errorf("expected *protoregistry.Files in GetSignersContext, got %T", c.protoFiles)
-	}
-
 	var errs []error
-	fs.RangeFiles(func(fd protoreflect.FileDescriptor) bool {
+	c.protoFiles.RangeFiles(func(fd protoreflect.FileDescriptor) bool {
 		for i := 0; i < fd.Services().Len(); i++ {
 			sd := fd.Services().Get(i)
 			// We use the heuristic that services named "Msg" are exactly the