solana-ibc: introduce error module; move Error enum there (#87)

The module is tiny at the moment but with time more variants will be
added to the variant which would otherwise live in the lib.rs file
making it grow in size even more.

common/blockchain/Cargo.toml

@@ -7,6 +7,7 @@ edition = "2021"
 [dependencies]
 borsh.workspace = true
 derive_more.workspace = true
+strum.workspace = true
 
 lib = { workspace = true, features = ["borsh"] }
 

common/blockchain/src/block.rs

@@ -45,7 +45,7 @@ pub struct Block<PK> {
 }
 
 /// Error while generating new block.
-#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+#[derive(Clone, Copy, Debug, PartialEq, Eq, strum::IntoStaticStr)]
 pub enum GenerateError {
     /// Host height went backwards.
     BadHostHeight,

common/blockchain/src/manager.rs

@@ -55,7 +55,9 @@ struct PendingBlock<PK> {
 pub struct BadGenesis;
 
 /// Error while generating a new block.
-#[derive(Clone, Debug, PartialEq, Eq, derive_more::From)]
+#[derive(
+    Clone, Debug, PartialEq, Eq, derive_more::From, strum::IntoStaticStr,
+)]
 pub enum GenerateError {
     /// Last block hasn’t been signed by enough validators yet.
     HasPendingBlock,

solana/solana-ibc/programs/solana-ibc/Cargo.toml

@@ -19,6 +19,7 @@ mocks = ["ibc/mocks", "ibc/std"]
 anchor-lang.workspace = true
 base64.workspace = true
 bytemuck.workspace = true
+derive_more.workspace = true
 ibc-proto.workspace = true
 ibc.workspace = true
 serde.workspace = true

solana/solana-ibc/programs/solana-ibc/src/error.rs

@@ -0,0 +1,37 @@
+/// Error returned when handling a request.
+// Note: When changing variants in the enum, try to preserve indexes of each
+// variant.  The position is translated into error code returned by Anchor and
+// keeping them consistent makes things easier.
+#[derive(strum::EnumDiscriminants, strum::IntoStaticStr)]
+#[strum_discriminants(repr(u32))]
+#[allow(clippy::enum_variant_names)]
+pub(crate) enum Error {
+    /// Error handling an IBC request.
+    RouterError(ibc::core::RouterError),
+}
+
+impl Error {
+    pub fn name(&self) -> String { <&'static str>::from(self).into() }
+}
+
+impl core::fmt::Display for Error {
+    fn fmt(&self, fmtr: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
+        match self {
+            Self::RouterError(err) => err.fmt(fmtr),
+        }
+    }
+}
+
+impl From<Error> for u32 {
+    fn from(err: Error) -> u32 {
+        let code = ErrorDiscriminants::from(err) as u32;
+        anchor_lang::error::ERROR_CODE_OFFSET + code
+    }
+}
+
+impl From<&Error> for u32 {
+    fn from(err: &Error) -> u32 {
+        let code = ErrorDiscriminants::from(err) as u32;
+        anchor_lang::error::ERROR_CODE_OFFSET + code
+    }
+}

solana/solana-ibc/programs/solana-ibc/src/lib.rs

@@ -10,6 +10,7 @@ use ibc::core::router::{Module, ModuleId, Router};
 const SOLANA_IBC_STORAGE_SEED: &[u8] = b"solana_ibc_storage";
 const TRIE_SEED: &[u8] = b"trie";
 const PACKET_SEED: &[u8] = b"packet";
+
 const CONNECTION_ID_PREFIX: &str = "connection-";
 const CHANNEL_ID_PREFIX: &str = "channel-";
 use ibc::core::MsgEnvelope;
@@ -21,6 +22,7 @@ declare_id!("EnfDJsAK7BGgetnmKzBx86CsgC5kfSPcsktFCQ4YLC81");
 mod client_state;
 mod consensus_state;
 mod ed25519;
+mod error;
 mod execution_context;
 mod storage;
 #[cfg(test)]
@@ -55,11 +57,9 @@ pub mod solana_ibc {
 
         {
             let mut router = store.clone();
-            if let Err(e) =
-                ibc::core::dispatch(&mut store, &mut router, message.clone())
-            {
-                return err!(Error::RouterError(&e));
-            }
+            ibc::core::dispatch(&mut store, &mut router, message.clone())
+                .map_err(error::Error::RouterError)
+                .map_err(|err| error!((&err)))?;
         }
         if let MsgEnvelope::Packet(packet) = message {
             // store the packet if not exists
@@ -89,7 +89,7 @@ pub struct Deliver<'info> {
     sender: Signer<'info>,
 
     /// The account holding private IBC storage.
-    #[account(init_if_needed, payer = sender, seeds = [SOLANA_IBC_STORAGE_SEED],bump, space = 10000)]
+    #[account(init_if_needed, payer = sender, seeds = [SOLANA_IBC_STORAGE_SEED], bump, space = 10000)]
     storage: Account<'info, storage::PrivateStorage>,
 
     /// The account holding provable IBC storage, i.e. the trie.
@@ -106,32 +106,6 @@ pub struct Deliver<'info> {
     system_program: Program<'info, System>,
 }
 
-/// Error returned when handling a request.
-#[derive(Clone, strum::AsRefStr, strum::EnumDiscriminants)]
-#[strum_discriminants(repr(u32))]
-pub enum Error<'a> {
-    RouterError(&'a ibc::core::RouterError),
-}
-
-impl Error<'_> {
-    pub fn name(&self) -> String { self.as_ref().into() }
-}
-
-impl core::fmt::Display for Error<'_> {
-    fn fmt(&self, fmtr: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
-        match self {
-            Self::RouterError(err) => write!(fmtr, "{err}"),
-        }
-    }
-}
-
-impl From<Error<'_>> for u32 {
-    fn from(err: Error<'_>) -> u32 {
-        let code = ErrorDiscriminants::from(err) as u32;
-        anchor_lang::error::ERROR_CODE_OFFSET + code
-    }
-}
-
 #[event]
 pub struct EmitIBCEvent {
     pub ibc_event: Vec<u8>,