fix(rust/signed-doc): handle validation errors with crate::error::Error

Author: saibatizoku

rust/signed_doc/src/metadata/additional_fields.rs

@@ -100,7 +100,7 @@ impl From<&AdditionalFields> for Vec<(Label, Value)> {
 }
 
 impl TryFrom<&ProtectedHeader> for AdditionalFields {
-    type Error = Vec<anyhow::Error>;
+    type Error = crate::error::Error;
 
     #[allow(clippy::too_many_lines)]
     fn try_from(protected: &ProtectedHeader) -> Result<Self, Self::Error> {
@@ -261,7 +261,7 @@ impl TryFrom<&ProtectedHeader> for AdditionalFields {
         if errors.is_empty() {
             Ok(extra)
         } else {
-            Err(errors)
+            Err(crate::error::Error(errors))
         }
     }
 }

rust/signed_doc/src/metadata/mod.rs

@@ -171,7 +171,7 @@ impl TryFrom<&coset::ProtectedHeader> for Metadata {
 
         let extra = AdditionalFields::try_from(protected).map_or_else(
             |e| {
-                errors.extend(e);
+                errors.extend(e.0);
                 None
             },
             Some,