feat: improve gateway response error logging

Enhance error handling when parsing gateway responses fails by:
- Adding trace logging of JSON structure when type parsing fails
- Adding error logging with raw response body when JSON parsing fails

CHANGELOG.md

@@ -11,6 +11,7 @@ and [Conventional Commits](https://www.conventionalcommits.org/en/v1.0.0/).
 - [chore] Add Debian package metadata
 
 ### Changed
+- [gateway] Improve error logging for response parsing failures
 - [protocol] Parse JSON as 64-bit and truncate internally
 
 ### Deprecated

src/gateway.rs

@@ -218,8 +218,23 @@ impl Gateway {
         }
 
         let response = self.http_client.execute(request).await?;
-        let result = response.json::<gateway::Response<T>>().await?;
-        trace!("{}: {result:#?}", T::METHOD);
+        let body = response.text().await?;
+
+        let result: gateway::Response<T> = match serde_json::from_str(&body) {
+            Ok(result) => {
+                trace!("{}: {result:#?}", T::METHOD);
+                result
+            }
+            Err(e) => {
+                if let Ok(json) = serde_json::from_str::<serde_json::Value>(&body) {
+                    trace!("{}: {json:#?}", T::METHOD);
+                } else {
+                    error!("{}: failed parsing response ({e:?})", T::METHOD);
+                    trace!("{body}");
+                }
+                return Err(e.into());
+            }
+        };
 
         Ok(result)
     }