feat: Support delegated targets roles in repo writer

client/errors.go

@@ -3,8 +3,6 @@ package client
 import (
 	"errors"
 	"fmt"
-
-	"github.com/theupdateframework/go-tuf/verify"
 )
 
 var (
@@ -49,20 +47,6 @@ func (e ErrMaxDelegations) Error() string {
 	return fmt.Sprintf("tuf: max delegation of %d reached searching for %s with snapshot version %d", e.MaxDelegations, e.Target, e.SnapshotVersion)
 }
 
-//lint:ignore U1000 unused
-func isDecodeFailedWithErrRoleThreshold(err error) bool {
-	e, ok := err.(ErrDecodeFailed)
-	if !ok {
-		return false
-	}
-	return isErrRoleThreshold(e.Err)
-}
-
-func isErrRoleThreshold(err error) bool {
-	_, ok := err.(verify.ErrRoleThreshold)
-	return ok
-}
-
 type ErrNotFound struct {
 	File string
 }

errors.go

@@ -88,3 +88,11 @@ type ErrPassphraseRequired struct {
 func (e ErrPassphraseRequired) Error() string {
 	return fmt.Sprintf("tuf: a passphrase is required to access the encrypted %s keys file", e.Role)
 }
+
+type ErrNoDelegatedTarget struct {
+	Path string
+}
+
+func (e ErrNoDelegatedTarget) Error() string {
+	return fmt.Sprintf("tuf: no delegated target for path %s", e.Path)
+}

local_store.go

@@ -14,7 +14,6 @@ import (
 
 	"github.com/theupdateframework/go-tuf/data"
 	"github.com/theupdateframework/go-tuf/encrypted"
-	"github.com/theupdateframework/go-tuf/internal/roles"
 	"github.com/theupdateframework/go-tuf/internal/sets"
 	"github.com/theupdateframework/go-tuf/pkg/keys"
 	"github.com/theupdateframework/go-tuf/util"
@@ -43,6 +42,8 @@ type LocalStore interface {
 	Commit(bool, map[string]int64, map[string]data.Hashes) error
 
 	// GetSigners return a list of signers for a role.
+	// This may include revoked keys, so the signers should not
+	// be used without filtering.
 	GetSigners(role string) ([]keys.Signer, error)
 
 	// SaveSigner adds a signer to a role.
@@ -222,8 +223,7 @@ func (f *fileSystemStore) stagedDir() string {
 }
 
 func isMetaFile(e os.DirEntry) (bool, error) {
-	name := e.Name()
-	if e.IsDir() || !(filepath.Ext(name) == ".json" && roles.IsTopLevelManifest(name)) {
+	if e.IsDir() || filepath.Ext(e.Name()) != ".json" {
 		return false, nil
 	}