Zero sized types (#121)

* Fix zero sized types.

* Cleanup.

* Expose genesis hash.

* Fix clippy warnings.

* Readd default type sizes for now.

* Cleanup ret type.

proc-macro/src/call.rs

@@ -54,9 +54,8 @@ pub fn call(s: Structure) -> TokenStream {
             const FUNCTION: &'static str = #call_name;
             fn events_decoder(
                 decoder: &mut #subxt::EventsDecoder<T>,
-            ) -> Result<(), #subxt::EventsError> {
-                decoder.#with_module()?;
-                Ok(())
+            ) {
+                decoder.#with_module();
             }
         }
 
@@ -125,9 +124,8 @@ mod tests {
                 const FUNCTION: &'static str = "transfer";
                 fn events_decoder(
                     decoder: &mut substrate_subxt::EventsDecoder<T>,
-                ) -> Result<(), substrate_subxt::EventsError> {
-                    decoder.with_balances()?;
-                    Ok(())
+                ) {
+                    decoder.with_balances();
                 }
             }
 

proc-macro/src/module.rs

@@ -85,7 +85,7 @@ pub fn module(_args: TokenStream, tokens: TokenStream) -> TokenStream {
             let module = utils::path_to_ident(path);
             let with_module = with_module_ident(module);
             Some(quote! {
-                self.#with_module()?;
+                self.#with_module();
             })
         } else {
             None
@@ -99,7 +99,7 @@ pub fn module(_args: TokenStream, tokens: TokenStream) -> TokenStream {
             let ident = &ty.ident;
             let ident_str = ident.to_string();
             Some(quote! {
-                self.register_type_size::<T::#ident>(#ident_str)?;
+                self.register_type_size::<T::#ident>(#ident_str);
             })
         } else {
             None
@@ -114,16 +114,15 @@ pub fn module(_args: TokenStream, tokens: TokenStream) -> TokenStream {
         /// `EventsDecoder` extension trait.
         pub trait #module_events_decoder {
             /// Registers this modules types.
-            fn #with_module(&mut self) -> Result<(), #subxt::EventsError>;
+            fn #with_module(&mut self);
         }
 
         impl<T: #module> #module_events_decoder for
             #subxt::EventsDecoder<T>
         {
-            fn #with_module(&mut self) -> Result<(), #subxt::EventsError> {
+            fn #with_module(&mut self) {
                 #(#bounds)*
                 #(#types)*
-                Ok(())
             }
         }
     }
@@ -167,16 +166,15 @@ mod tests {
             /// `EventsDecoder` extension trait.
             pub trait BalancesEventsDecoder {
                 /// Registers this modules types.
-                fn with_balances(&mut self) -> Result<(), substrate_subxt::EventsError>;
+                fn with_balances(&mut self);
             }
 
             impl<T: Balances> BalancesEventsDecoder for
                 substrate_subxt::EventsDecoder<T>
             {
-                fn with_balances(&mut self) -> Result<(), substrate_subxt::EventsError> {
-                    self.with_system()?;
-                    self.register_type_size::<T::Balance>("Balance")?;
-                    Ok(())
+                fn with_balances(&mut self) {
+                    self.with_system();
+                    self.register_type_size::<T::Balance>("Balance");
                 }
             }
         };

src/events.rs

@@ -28,7 +28,6 @@ use std::{
         HashMap,
         HashSet,
     },
-    convert::TryFrom,
     marker::{
         PhantomData,
         Send,
@@ -87,51 +86,43 @@ pub struct EventsDecoder<T> {
     marker: PhantomData<fn() -> T>,
 }
 
-impl<T: System> TryFrom<Metadata> for EventsDecoder<T> {
-    type Error = EventsError;
-
-    fn try_from(metadata: Metadata) -> Result<Self, Self::Error> {
+impl<T: System> EventsDecoder<T> {
+    /// Creates a new `EventsDecoder`.
+    pub fn new(metadata: Metadata) -> Self {
         let mut decoder = Self {
             metadata,
             type_sizes: HashMap::new(),
             marker: PhantomData,
         };
         // register default event arg type sizes for dynamic decoding of events
-        decoder.register_type_size::<bool>("bool")?;
-        decoder.register_type_size::<u32>("ReferendumIndex")?;
-        decoder.register_type_size::<[u8; 16]>("Kind")?;
-        decoder.register_type_size::<[u8; 32]>("AuthorityId")?;
-        decoder.register_type_size::<u8>("u8")?;
-        decoder.register_type_size::<u32>("u32")?;
-        decoder.register_type_size::<u32>("AccountIndex")?;
-        decoder.register_type_size::<u32>("SessionIndex")?;
-        decoder.register_type_size::<u32>("PropIndex")?;
-        decoder.register_type_size::<u32>("ProposalIndex")?;
-        decoder.register_type_size::<u32>("AuthorityIndex")?;
-        decoder.register_type_size::<u64>("AuthorityWeight")?;
-        decoder.register_type_size::<u32>("MemberCount")?;
-        decoder.register_type_size::<T::AccountId>("AccountId")?;
-        decoder.register_type_size::<T::BlockNumber>("BlockNumber")?;
-        decoder.register_type_size::<T::Hash>("Hash")?;
-        decoder.register_type_size::<u8>("VoteThreshold")?;
-
-        Ok(decoder)
+        decoder.register_type_size::<bool>("bool");
+        decoder.register_type_size::<u32>("ReferendumIndex");
+        decoder.register_type_size::<[u8; 16]>("Kind");
+        decoder.register_type_size::<[u8; 32]>("AuthorityId");
+        decoder.register_type_size::<u8>("u8");
+        decoder.register_type_size::<u32>("u32");
+        decoder.register_type_size::<u32>("AccountIndex");
+        decoder.register_type_size::<u32>("SessionIndex");
+        decoder.register_type_size::<u32>("PropIndex");
+        decoder.register_type_size::<u32>("ProposalIndex");
+        decoder.register_type_size::<u32>("AuthorityIndex");
+        decoder.register_type_size::<u64>("AuthorityWeight");
+        decoder.register_type_size::<u32>("MemberCount");
+        decoder.register_type_size::<T::AccountId>("AccountId");
+        decoder.register_type_size::<T::BlockNumber>("BlockNumber");
+        decoder.register_type_size::<T::Hash>("Hash");
+        decoder.register_type_size::<u8>("VoteThreshold");
+        decoder
     }
-}
 
-impl<T: System> EventsDecoder<T> {
     /// Register a type.
-    pub fn register_type_size<U>(&mut self, name: &str) -> Result<usize, EventsError>
+    pub fn register_type_size<U>(&mut self, name: &str) -> usize
     where
         U: Default + Codec + Send + 'static,
     {
         let size = U::default().encode().len();
-        if size > 0 {
-            self.type_sizes.insert(name.to_string(), size);
-            Ok(size)
-        } else {
-            Err(EventsError::TypeSizeUnavailable(name.to_owned()))
-        }
+        self.type_sizes.insert(name.to_string(), size);
+        size
     }
 
     /// Check missing type sizes.
@@ -156,7 +147,7 @@ impl<T: System> EventsDecoder<T> {
                 }
             }
         }
-        if missing.len() > 0 {
+        if !missing.is_empty() {
             log::warn!(
                 "The following primitive types do not have registered sizes: {:?} \
                 If any of these events are received, an error will occur since we cannot decode them",

src/frame/mod.rs

@@ -17,10 +17,7 @@
 //! Implements support for built-in runtime modules.
 
 use crate::{
-    events::{
-        EventsDecoder,
-        EventsError,
-    },
+    events::EventsDecoder,
     metadata::{
         Metadata,
         MetadataError,
@@ -62,9 +59,7 @@ pub trait Call<T>: Encode {
     /// Function name.
     const FUNCTION: &'static str;
     /// Load event decoder.
-    fn events_decoder(_decoder: &mut EventsDecoder<T>) -> Result<(), EventsError> {
-        Ok(())
-    }
+    fn events_decoder(_decoder: &mut EventsDecoder<T>) {}
 }
 
 /// Event trait.

src/lib.rs

@@ -65,10 +65,7 @@ use sp_runtime::{
     MultiSignature,
 };
 use sp_version::RuntimeVersion;
-use std::{
-    convert::TryFrom,
-    marker::PhantomData,
-};
+use std::marker::PhantomData;
 
 mod error;
 mod events;
@@ -148,11 +145,7 @@ impl<T: System + Send + Sync, S, E> ClientBuilder<T, S, E> {
         let client = if let Some(client) = self.client {
             client
         } else {
-            let url = self
-                .url
-                .as_ref()
-                .map(|s| &**s)
-                .unwrap_or("ws://127.0.0.1:9944");
+            let url = self.url.as_deref().unwrap_or("ws://127.0.0.1:9944");
             if url.starts_with("ws://") || url.starts_with("wss://") {
                 jsonrpsee::ws_client(url).await?
             } else {
@@ -198,6 +191,11 @@ impl<T: System, S, E> Clone for Client<T, S, E> {
 }
 
 impl<T: System, S, E> Client<T, S, E> {
+    /// Returns the genesis hash.
+    pub fn genesis(&self) -> &T::Hash {
+        &self.genesis_hash
+    }
+
     /// Returns the chain metadata.
     pub fn metadata(&self) -> &Metadata {
         &self.metadata
@@ -362,11 +360,11 @@ where
     }
 
     /// Returns an events decoder for a call.
-    pub fn events_decoder<C: Call<T>>(&self) -> Result<EventsDecoder<T>, Error> {
+    pub fn events_decoder<C: Call<T>>(&self) -> EventsDecoder<T> {
         let metadata = self.metadata().clone();
-        let mut decoder = EventsDecoder::try_from(metadata)?;
-        C::events_decoder(&mut decoder)?;
-        Ok(decoder)
+        let mut decoder = EventsDecoder::new(metadata);
+        C::events_decoder(&mut decoder);
+        decoder
     }
 
     /// Create and submit an extrinsic and return corresponding Hash if successful
@@ -421,7 +419,7 @@ where
         <<E as SignedExtra<T>>::Extra as SignedExtension>::AdditionalSigned: Send + Sync,
     {
         let extrinsic = self.create_signed(call, signer).await?;
-        let decoder = self.events_decoder::<C>()?;
+        let decoder = self.events_decoder::<C>();
         self.submit_and_watch_extrinsic(extrinsic, decoder).await
     }
 }

src/metadata.rs

@@ -223,8 +223,7 @@ impl StorageMetadata {
     }
 
     pub fn default<V: Decode>(&self) -> Result<V, MetadataError> {
-        Decode::decode(&mut &self.default[..])
-            .map_err(|err| MetadataError::DefaultError(err))
+        Decode::decode(&mut &self.default[..]).map_err(MetadataError::DefaultError)
     }
 
     pub fn hash(hasher: &StorageHasher, bytes: &[u8]) -> Vec<u8> {

src/rpc.rs

@@ -203,7 +203,7 @@ impl<T: System> Rpc<T> {
         &self,
         block_number: Option<BlockNumber<T>>,
     ) -> Result<Option<T::Hash>, Error> {
-        let block_number = block_number.map(|bn| ListOrValue::Value(bn));
+        let block_number = block_number.map(ListOrValue::Value);
         let params = Params::Array(vec![to_json_value(block_number)?]);
         let list_or_value = self.client.request("chain_getBlockHash", params).await?;
         match list_or_value {
@@ -490,7 +490,7 @@ pub async fn wait_for_block_events<T: System>(
                 }
             }
         }
-        return if events.len() > 0 {
+        return if !events.is_empty() {
             Ok(ExtrinsicSuccess {
                 block: block_hash,
                 extrinsic: ext_hash,