style: rename ErrInsufficientKeys to ErrNoKeys

errors.go

@@ -28,12 +28,12 @@ func (e ErrFileNotFound) Error() string {
 	return fmt.Sprintf("tuf: file not found %s", e.Path)
 }
 
-type ErrInsufficientKeys struct {
+type ErrNoKeys struct {
 	Name string
 }
 
-func (e ErrInsufficientKeys) Error() string {
-	return fmt.Sprintf("tuf: insufficient keys to sign %s", e.Name)
+func (e ErrNoKeys) Error() string {
+	return fmt.Sprintf("tuf: no keys available to sign %s", e.Name)
 }
 
 type ErrInsufficientSignatures struct {

repo.go

@@ -512,8 +512,7 @@ func (r *Repo) setTopLevelMeta(roleFilename string, meta interface{}) error {
 // SignPayload signs the given payload using the key(s) associated with role.
 //
 // It returns the total number of keys used for signing, 0 (along with
-// ErrInsufficientKeys) if no keys were found, or -1 (along with an error) in
-// error cases.
+// ErrNoKeys) if no keys were found, or -1 (along with an error) in error cases.
 func (r *Repo) SignPayload(role string, payload *data.Signed) (int, error) {
 	if !roles.IsTopLevelRole(role) {
 		return -1, ErrInvalidRole{role, "only signing top-level metadata supported"}
@@ -524,7 +523,7 @@ func (r *Repo) SignPayload(role string, payload *data.Signed) (int, error) {
 		return -1, err
 	}
 	if len(keys) == 0 {
-		return 0, ErrInsufficientKeys{role}
+		return 0, ErrNoKeys{role}
 	}
 	for _, k := range keys {
 		if err = sign.Sign(payload, k); err != nil {
@@ -542,8 +541,8 @@ func (r *Repo) Sign(roleFilename string) error {
 
 	role := strings.TrimSuffix(roleFilename, ".json")
 	numKeys, err := r.SignPayload(role, signed)
-	if errors.Is(err, ErrInsufficientKeys{role}) {
-		return ErrInsufficientKeys{roleFilename}
+	if errors.Is(err, ErrNoKeys{role}) {
+		return ErrNoKeys{roleFilename}
 	} else if err != nil {
 		return err
 	}

repo_test.go

@@ -635,8 +635,8 @@ func (rs *RepoSuite) TestSign(c *C) {
 
 	c.Assert(r.Sign("foo.json"), Equals, ErrMissingMetadata{"foo.json"})
 
-	// signing with no keys returns ErrInsufficientKeys
-	c.Assert(r.Sign("root.json"), Equals, ErrInsufficientKeys{"root.json"})
+	// signing with no keys returns ErrNoKeys
+	c.Assert(r.Sign("root.json"), Equals, ErrNoKeys{"root.json"})
 
 	checkSigIDs := func(keyIDs ...string) {
 		meta, err := local.GetMeta()
@@ -1908,7 +1908,7 @@ func (rs *RepoSuite) TestOfflineFlow(c *C) {
 	_, err = r.SignPayload("badrole", &signed)
 	c.Assert(err, Equals, ErrInvalidRole{"badrole", "only signing top-level metadata supported"})
 	_, err = r.SignPayload("targets", &signed)
-	c.Assert(err, Equals, ErrInsufficientKeys{"targets"})
+	c.Assert(err, Equals, ErrNoKeys{"targets"})
 	numKeys, err := r.SignPayload("root", &signed)
 	c.Assert(err, IsNil)
 	c.Assert(numKeys, Equals, 1)