rpc v2 archive: more verbose error types in API (#8109)

Builds on #8104

---------

Co-authored-by: James Wilson <[email protected]>
Co-authored-by: cmd[bot] <41898282+github-actions[bot]@users.noreply.github.com>

Author: 3 people

prdoc/pr_8109.prdoc

@@ -0,0 +1,7 @@
+title: 'rpc v2 archive: more verbose error types in API'
+doc:
+- audience: Node Dev
+  description: 'This PR changes the error types to more precise rather than arbitrary JSON-RPC error'
+crates:
+- name: sc-rpc-spec-v2
+  bump: major

substrate/client/rpc-spec-v2/src/archive/api.rs

@@ -19,12 +19,13 @@
 //! API trait of the archive methods.
 
 use crate::{
+	archive::error::{Error, Infallible},
 	common::events::{
 		ArchiveStorageDiffEvent, ArchiveStorageDiffItem, ArchiveStorageEvent, StorageQuery,
 	},
 	MethodResult,
 };
-use jsonrpsee::{core::RpcResult, proc_macros::rpc};
+use jsonrpsee::proc_macros::rpc;
 
 #[rpc(client, server)]
 pub trait ArchiveApi<Hash> {
@@ -37,7 +38,7 @@ pub trait ArchiveApi<Hash> {
 	///
 	/// This method is unstable and subject to change in the future.
 	#[method(name = "archive_v1_body")]
-	fn archive_v1_body(&self, hash: Hash) -> RpcResult<Option<Vec<String>>>;
+	fn archive_v1_body(&self, hash: Hash) -> Result<Option<Vec<String>>, Infallible>;
 
 	/// Get the chain's genesis hash.
 	///
@@ -47,7 +48,7 @@ pub trait ArchiveApi<Hash> {
 	///
 	/// This method is unstable and subject to change in the future.
 	#[method(name = "archive_v1_genesisHash")]
-	fn archive_v1_genesis_hash(&self) -> RpcResult<String>;
+	fn archive_v1_genesis_hash(&self) -> Result<String, Infallible>;
 
 	/// Get the block's header.
 	///
@@ -58,7 +59,7 @@ pub trait ArchiveApi<Hash> {
 	///
 	/// This method is unstable and subject to change in the future.
 	#[method(name = "archive_v1_header")]
-	fn archive_v1_header(&self, hash: Hash) -> RpcResult<Option<String>>;
+	fn archive_v1_header(&self, hash: Hash) -> Result<Option<String>, Infallible>;
 
 	/// Get the height of the current finalized block.
 	///
@@ -68,7 +69,7 @@ pub trait ArchiveApi<Hash> {
 	///
 	/// This method is unstable and subject to change in the future.
 	#[method(name = "archive_v1_finalizedHeight")]
-	fn archive_v1_finalized_height(&self) -> RpcResult<u64>;
+	fn archive_v1_finalized_height(&self) -> Result<u64, Infallible>;
 
 	/// Get the hashes of blocks from the given height.
 	///
@@ -79,7 +80,7 @@ pub trait ArchiveApi<Hash> {
 	///
 	/// This method is unstable and subject to change in the future.
 	#[method(name = "archive_v1_hashByHeight")]
-	fn archive_v1_hash_by_height(&self, height: u64) -> RpcResult<Vec<String>>;
+	fn archive_v1_hash_by_height(&self, height: u64) -> Result<Vec<String>, Error>;
 
 	/// Call into the Runtime API at a specified block's state.
 	///
@@ -92,7 +93,7 @@ pub trait ArchiveApi<Hash> {
 		hash: Hash,
 		function: String,
 		call_parameters: String,
-	) -> RpcResult<MethodResult>;
+	) -> Result<MethodResult, Error>;
 
 	/// Returns storage entries at a specific block's state.
 	///

substrate/client/rpc-spec-v2/src/archive/archive.rs

@@ -20,7 +20,9 @@
 
 use crate::{
 	archive::{
-		archive_storage::ArchiveStorageDiff, error::Error as ArchiveError, ArchiveApiServer,
+		archive_storage::ArchiveStorageDiff,
+		error::{Error as ArchiveError, Infallible},
+		ArchiveApiServer,
 	},
 	common::{
 		events::{
@@ -33,10 +35,7 @@ use crate::{
 
 use codec::Encode;
 use futures::FutureExt;
-use jsonrpsee::{
-	core::{async_trait, RpcResult},
-	PendingSubscriptionSink,
-};
+use jsonrpsee::{core::async_trait, PendingSubscriptionSink};
 use sc_client_api::{
 	Backend, BlockBackend, BlockchainEvents, CallExecutor, ChildInfo, ExecutorProvider, StorageKey,
 	StorageProvider,
@@ -117,7 +116,7 @@ where
 		+ StorageProvider<Block, BE>
 		+ 'static,
 {
-	fn archive_v1_body(&self, hash: Block::Hash) -> RpcResult<Option<Vec<String>>> {
+	fn archive_v1_body(&self, hash: Block::Hash) -> Result<Option<Vec<String>>, Infallible> {
 		let Ok(Some(signed_block)) = self.client.block(hash) else { return Ok(None) };
 
 		let extrinsics = signed_block
@@ -130,21 +129,21 @@ where
 		Ok(Some(extrinsics))
 	}
 
-	fn archive_v1_genesis_hash(&self) -> RpcResult<String> {
+	fn archive_v1_genesis_hash(&self) -> Result<String, Infallible> {
 		Ok(self.genesis_hash.clone())
 	}
 
-	fn archive_v1_header(&self, hash: Block::Hash) -> RpcResult<Option<String>> {
+	fn archive_v1_header(&self, hash: Block::Hash) -> Result<Option<String>, Infallible> {
 		let Ok(Some(header)) = self.client.header(hash) else { return Ok(None) };
 
 		Ok(Some(hex_string(&header.encode())))
 	}
 
-	fn archive_v1_finalized_height(&self) -> RpcResult<u64> {
+	fn archive_v1_finalized_height(&self) -> Result<u64, Infallible> {
 		Ok(self.client.info().finalized_number.saturated_into())
 	}
 
-	fn archive_v1_hash_by_height(&self, height: u64) -> RpcResult<Vec<String>> {
+	fn archive_v1_hash_by_height(&self, height: u64) -> Result<Vec<String>, ArchiveError> {
 		let height: NumberFor<Block> = U256::from(height)
 			.try_into()
 			.map_err(|_| ArchiveError::InvalidParam(format!("Invalid block height: {}", height)))?;
@@ -200,7 +199,7 @@ where
 		hash: Block::Hash,
 		function: String,
 		call_parameters: String,
-	) -> RpcResult<MethodResult> {
+	) -> Result<MethodResult, ArchiveError> {
 		let call_parameters = Bytes::from(parse_hex_param(call_parameters)?);
 
 		let result =

substrate/client/rpc-spec-v2/src/archive/error.rs

@@ -55,3 +55,14 @@ impl From<Error> for ErrorObject<'static> {
 		.into()
 	}
 }
+
+/// The error type for errors that can never happen.
+//
+// NOTE: Can't use std::convert::Infallible because of the orphan-rule
+pub enum Infallible {}
+
+impl From<Infallible> for ErrorObject<'static> {
+	fn from(e: Infallible) -> Self {
+		match e {}
+	}
+}