better era error messages

mithril-aggregator/src/runtime/error.rs

@@ -60,9 +60,6 @@ pub enum RuntimeError {
     #[error("signer registration error: {0}")]
     SignerRegistration(#[from] SignerRegistrationError),
 
-    #[error("era not supported: {0}")]
-    EraNotSupported(String),
-
     #[error("general error: {0}")]
     General(Box<dyn StdError + Sync + Send>),
 }

mithril-common/src/era/era_reader.rs

@@ -57,6 +57,7 @@ impl EraEpochToken {
     /// software.
     pub fn get_current_supported_era(&self) -> Result<SupportedEra, UnsupportedEraError> {
         SupportedEra::from_str(&self.current_era.name)
+            .map_err(|_| UnsupportedEraError::new(&self.current_era.name))
     }
 
     /// Return the [EraMarker] of the current Era.
@@ -75,7 +76,10 @@ impl EraEpochToken {
     /// for upgrade.
     pub fn get_next_supported_era(&self) -> Result<Option<SupportedEra>, UnsupportedEraError> {
         match self.next_era.as_ref() {
-            Some(marker) => Ok(Some(SupportedEra::from_str(&marker.name)?)),
+            Some(marker) => Ok(Some(
+                SupportedEra::from_str(&marker.name)
+                    .map_err(|_| UnsupportedEraError::new(&self.current_era.name))?,
+            )),
             None => Ok(None),
         }
     }

mithril-common/src/era/supported_era.rs

@@ -1,9 +1,22 @@
 use serde::{Deserialize, Serialize};
 use strum::IntoEnumIterator;
 use strum_macros::{Display, EnumIter, EnumString};
+use thiserror::Error;
 
 /// Error related to [SupportedEra] String parsing implementation.
-pub type UnsupportedEraError = strum::ParseError;
+#[derive(Debug, Error)]
+#[error("Unsupported Era '{era}'.")]
+pub struct UnsupportedEraError {
+    era: String,
+}
+
+impl UnsupportedEraError {
+    pub fn new(era: &str) -> Self {
+        Self {
+            era: era.to_owned(),
+        }
+    }
+}
 
 /// The era that the software is running or will run
 #[derive(