Some corrections of the linera-execution code. (#4514)

## Motivation

The `CreateApplication` return value has the possibility of an error,
which can never happen.

## Proposal

The `Result<_,_>` return type for `CreateApplication` is eliminated.

Other changes are made:
* Simplify the processing of errors when possible.
* Remove the conversion `.into_iter().collect()` when the input and
return type are the same.
* Remove the dependency on the orders of the return values for the
tests.

## Test Plan

CI

## Release Plan

- Nothing to do / These changes follow the usual release cycle.

## Links

None.

Author: MathieuDutSik

linera-execution/src/execution_state_actor.rs

@@ -175,8 +175,7 @@ where
             }
 
             OwnerBalances { callback } => {
-                let balances = self.state.system.balances.index_values().await?;
-                callback.respond(balances.into_iter().collect());
+                callback.respond(self.state.system.balances.index_values().await?);
             }
 
             BalanceOwners { callback } => {
@@ -379,7 +378,7 @@ where
                         self.txn_tracker,
                     )
                     .await?;
-                callback.respond(Ok(create_application_result));
+                callback.respond(create_application_result);
             }
 
             PerformHttpRequest {
@@ -1113,7 +1112,7 @@ pub enum ExecutionRequest {
         parameters: Vec<u8>,
         required_application_ids: Vec<ApplicationId>,
         #[debug(skip)]
-        callback: Sender<Result<CreateApplicationResult, ExecutionError>>,
+        callback: Sender<CreateApplicationResult>,
     },
 
     PerformHttpRequest {

linera-execution/src/runtime.rs

@@ -860,16 +860,14 @@ where
 
         this.resource_controller.track_http_request()?;
 
-        let response = this
-            .execution_state_sender
+        this.execution_state_sender
             .send_request(|callback| ExecutionRequest::PerformHttpRequest {
                 request,
                 http_responses_are_oracle_responses:
                     Self::LIMIT_HTTP_RESPONSE_SIZE_TO_ORACLE_RESPONSE_SIZE,
                 callback,
             })?
-            .recv_response()?;
-        Ok(response)
+            .recv_response()
     }
 
     fn assert_before(&mut self, timestamp: Timestamp) -> Result<(), ExecutionError> {
@@ -897,8 +895,7 @@ where
         let blob_id = hash.into();
         this.execution_state_sender
             .send_request(|callback| ExecutionRequest::AssertBlobExists { blob_id, callback })?
-            .recv_response()?;
-        Ok(())
+            .recv_response()
     }
 }
 
@@ -1467,7 +1464,7 @@ impl ContractRuntime for ContractSyncRuntimeHandle {
                 required_application_ids,
                 callback,
             })?
-            .recv_response()??;
+            .recv_response()?;
 
         let contract = self.inner().prepare_for_call(self.clone(), true, app_id)?;
 

linera-execution/tests/service_runtime_apis.rs

@@ -3,7 +3,10 @@
 
 #![allow(clippy::field_reassign_with_default)]
 
-use std::{collections::BTreeMap, vec};
+use std::{
+    collections::{BTreeMap, BTreeSet},
+    vec,
+};
 
 use linera_base::{data_types::Amount, identifiers::AccountOwner};
 use linera_execution::{
@@ -116,8 +119,12 @@ async fn test_read_owner_balances_system_api(
 
     application.expect_call(ExpectedCall::handle_query(move |runtime, _query| {
         assert_eq!(
-            runtime.read_owner_balances().unwrap(),
-            accounts.into_iter().collect::<Vec<_>>(),
+            runtime
+                .read_owner_balances()
+                .unwrap()
+                .into_iter()
+                .collect::<BTreeMap<_, _>>(),
+            accounts,
         );
         Ok(vec![])
     }));
@@ -148,8 +155,12 @@ async fn test_read_balance_owners_system_api(
 
     application.expect_call(ExpectedCall::handle_query(move |runtime, _query| {
         assert_eq!(
-            runtime.read_balance_owners().unwrap(),
-            accounts.keys().copied().collect::<Vec<_>>()
+            runtime
+                .read_balance_owners()
+                .unwrap()
+                .into_iter()
+                .collect::<BTreeSet<_>>(),
+            accounts.keys().copied().collect::<BTreeSet<_>>()
         );
         Ok(vec![])
     }));