fix: don't wrap rpc error in DisconnectedWillReconnect in reconnecting rpc client (#1904)

* fix: don't wrap rpc err in DisconnectedWillRecon

* add clarifying comment

* fix no-std-test build

* fix no-std-test build v2

subxt/src/backend/rpc/reconnecting_rpc_client/mod.rs

@@ -427,7 +427,13 @@ impl RpcClientT for RpcClient {
         async {
             self.request(method.to_string(), params)
                 .await
-                .map_err(|e| SubxtRpcError::DisconnectedWillReconnect(e.to_string()))
+                .map_err(|e| match e {
+                    Error::DisconnectedWillReconnect(e) => {
+                        SubxtRpcError::DisconnectedWillReconnect(e.to_string())
+                    }
+                    Error::Dropped => SubxtRpcError::ClientError(Box::new(e)),
+                    Error::RpcError(e) => SubxtRpcError::ClientError(Box::new(e)),
+                })
         }
         .boxed()
     }
@@ -449,7 +455,11 @@ impl RpcClientT for RpcClient {
                 SubscriptionId::Str(s) => s.to_string(),
             };
             let stream = sub
-                .map_err(|e| SubxtRpcError::DisconnectedWillReconnect(e.to_string()))
+                // NOTE: The stream emits only one error `DisconnectWillReconnect if the connection was lost
+                // and safe to wrap it in a `SubxtRpcError::DisconnectWillReconnect` here
+                .map_err(|e: DisconnectedWillReconnect| {
+                    SubxtRpcError::DisconnectedWillReconnect(e.to_string())
+                })
                 .boxed();
 
             Ok(RawRpcSubscription {

testing/no-std-tests/src/main.rs

@@ -3,12 +3,11 @@
 // see LICENSE for license details.
 
 #![allow(internal_features)]
-#![feature(lang_items, start)]
+#![feature(lang_items, alloc_error_handler)]
-#![feature(alloc_error_handler)]
 #![no_std]
+#![no_main]
 
-#[start]
+pub extern "C" fn _start(_argc: isize, _argv: *const *const u8) -> isize {
-fn start(_argc: isize, _argv: *const *const u8) -> isize {
     compile_test();
     0
 }
@@ -60,11 +59,10 @@ fn compile_test() {
 
     // Subxt Core compiles:
     let _era = subxt_core::utils::Era::Immortal;
-    
 }
 
 #[subxt_macro::subxt(
     runtime_metadata_path = "../../artifacts/polkadot_metadata_full.scale",
-    crate="::subxt_core"
+    crate = "::subxt_core"
 )]
-pub mod polkadot{}
+pub mod polkadot {}