refactor(proto): start replacing anyhow with thiserror

proto/src/message/frontend.rs

@@ -2,6 +2,7 @@ use crate::message::primitive::data::MessageData;
 use crate::message::primitive::pgstring::PgString;
 use crate::message::proto_message::ProtoMessage;
 use bincode::{Decode, Encode};
+use crate::message::errors::{ProtoDeserializeError, ProtoSerializeError};
 
 #[derive(Debug)]
 pub enum FrontendMessage {
@@ -17,18 +18,18 @@ impl ProtoMessage for FrontendMessage {
         }
     }
 
-    fn serialize(&self) -> anyhow::Result<Vec<u8>> {
+    fn serialize(&self) -> Result<Vec<u8>, ProtoSerializeError> {
         match self {
             FrontendMessage::Query(data) => data.serialize(),
             FrontendMessage::Terminate => Ok(Vec::with_capacity(0)),
         }
     }
 
-    fn deserialize(variant: u8, data: &[u8]) -> anyhow::Result<Self> {
+    fn deserialize(variant: u8, data: &[u8]) -> Result<Self, ProtoDeserializeError> {
         match variant {
             b'Q' => Ok(FrontendMessage::Query(QueryData::deserialize(data)?)),
             b'X' => Ok(FrontendMessage::Terminate),
-            v => Err(anyhow::anyhow!("Unknown frontend message variant: {v}")),
+            v => Err(ProtoDeserializeError::InvalidVariant(v)),
         }
     }
 }
@@ -40,6 +41,7 @@ pub struct QueryData {
 
 #[cfg(test)]
 mod tests {
+    use crate::message::backend::BackendMessage;
     use super::*;
 
     #[test]
@@ -65,4 +67,13 @@ mod tests {
         let message = FrontendMessage::deserialize(variant, &raw).unwrap();
         assert!(matches!(message, FrontendMessage::Terminate));
     }
+
+    #[test]
+    fn test_unknown_variant() {
+        let variant = 0;
+        let data = vec![1, 2, 3];
+
+        let message = BackendMessage::deserialize(variant, &data);
+        assert!(matches!(message, Err(ProtoDeserializeError::InvalidVariant(0))));
+    }
 }