better serde decode err

Author: ltitanb

crates/common/src/pbs/error.rs

@@ -14,13 +14,13 @@ pub enum PbsError {
     #[error("reqwest error: {0}")]
     Reqwest(#[from] reqwest::Error),
 
-    #[error("serde decode error: {0}")]
-    SerdeDecodeError(#[from] serde_json::Error),
+    #[error("json decode error: {err}, raw:\n{raw}")]
+    JsonDecode { err: serde_json::Error, raw: String },
 
     #[error("relay response error. Code: {code}, err: {error_msg}")]
     RelayResponse { error_msg: String, code: u16 },
 
-    #[error("Response size exceeds 10MB! Got: {payload_size}")]
+    #[error("response size exceeds 10MB! Got: {payload_size}")]
     PayloadTooLarge { payload_size: usize },
 
     #[error("failed validating relay response: {0}")]

crates/pbs/src/mev_boost/get_header.rs

@@ -264,7 +264,15 @@ async fn send_one_get_header(
         return Ok((start_request_time, None));
     }
 
-    let get_header_response: GetHeaderResponse = serde_json::from_slice(&response_bytes)?;
+    let get_header_response = match serde_json::from_slice::<GetHeaderResponse>(&response_bytes) {
+        Ok(parsed) => parsed,
+        Err(err) => {
+            return Err(PbsError::JsonDecode {
+                err,
+                raw: String::from_utf8_lossy(&response_bytes).into_owned(),
+            });
+        }
+    };
 
     debug!(
         latency = ?request_latency,

crates/pbs/src/mev_boost/submit_block.rs

@@ -110,7 +110,16 @@ async fn send_submit_block(
         return Err(err);
     };
 
-    let block_response: SubmitBlindedBlockResponse = serde_json::from_slice(&response_bytes)?;
+    let block_response = match serde_json::from_slice::<SubmitBlindedBlockResponse>(&response_bytes)
+    {
+        Ok(parsed) => parsed,
+        Err(err) => {
+            return Err(PbsError::JsonDecode {
+                err,
+                raw: String::from_utf8_lossy(&response_bytes).into_owned(),
+            });
+        }
+    };
 
     debug!(
         latency = ?request_latency,