feat(contract): return multicall pending transaction (#2044)

* feat(contract): return multicall pending transaction

* fix: tests

* docs: update CHANGELOG.md

Author: DaniPopes

Diff for: CHANGELOG.md

@@ -291,6 +291,8 @@
 
 ### Unreleased
 
+- Return pending transaction from `Multicall::send`
+  [#2044](https://github.com/gakonst/ethers-rs/pull/2044)
 - Add abigen to default features
   [#1684](https://github.com/gakonst/ethers-rs/pull/1684)
 - Add extra Multicall helper methods

Diff for: ethers-contract/src/contract.rs

@@ -4,21 +4,18 @@ use crate::{
     event::{EthEvent, Event},
     EthLogDecode,
 };
-
 use ethers_core::{
     abi::{Abi, Detokenize, Error, EventExt, Function, Tokenize},
     types::{Address, Filter, Selector, ValueOrArray},
 };
+use ethers_providers::Middleware;
+use std::{marker::PhantomData, sync::Arc};
 
 #[cfg(not(feature = "legacy"))]
 use ethers_core::types::Eip1559TransactionRequest;
 #[cfg(feature = "legacy")]
 use ethers_core::types::TransactionRequest;
 
-use ethers_providers::Middleware;
-
-use std::{fmt::Debug, marker::PhantomData, sync::Arc};
-
 /// A Contract is an abstraction of an executable program on the Ethereum Blockchain.
 /// It has code (called byte code) as well as allocated long-term memory
 /// (called storage). Every deployed Contract has an address, which is used to connect
@@ -161,6 +158,7 @@ pub struct Contract<M> {
 
 impl<M> std::ops::Deref for Contract<M> {
     type Target = BaseContract;
+
     fn deref(&self) -> &Self::Target {
         &self.base_contract
     }
@@ -177,19 +175,24 @@ impl<M> Clone for Contract<M> {
 }
 
 impl<M> Contract<M> {
-    /// Returns the contract's address
+    /// Returns the contract's address.
     pub fn address(&self) -> Address {
         self.address
     }
 
-    /// Returns a reference to the contract's ABI
+    /// Returns a reference to the contract's ABI.
     pub fn abi(&self) -> &Abi {
         &self.base_contract.abi
     }
 
-    /// Returns a pointer to the contract's client
+    /// Returns a pointer to the contract's client.
     pub fn client(&self) -> Arc<M> {
-        self.client.clone()
+        Arc::clone(&self.client)
+    }
+
+    /// Returns a reference to the contract's client.
+    pub fn client_ref(&self) -> &M {
+        Arc::as_ref(&self.client)
     }
 }
 
@@ -301,10 +304,7 @@ impl<M: Middleware> Contract<M> {
     ///
     /// Clones `self` internally
     #[must_use]
-    pub fn at<T: Into<Address>>(&self, address: T) -> Self
-    where
-        M: Clone,
-    {
+    pub fn at<T: Into<Address>>(&self, address: T) -> Self {
         let mut this = self.clone();
         this.address = address.into();
         this
@@ -314,10 +314,7 @@ impl<M: Middleware> Contract<M> {
     ///
     /// Clones `self` internally
     #[must_use]
-    pub fn connect<N>(&self, client: Arc<N>) -> Contract<N>
-    where
-        N: Clone,
-    {
+    pub fn connect<N>(&self, client: Arc<N>) -> Contract<N> {
         Contract { base_contract: self.base_contract.clone(), client, address: self.address }
     }
 }

Diff for: ethers-contract/src/multicall/mod.rs

@@ -4,9 +4,9 @@ use crate::{
 };
 use ethers_core::{
     abi::{AbiDecode, Detokenize, Function, Token},
-    types::{Address, BlockNumber, Bytes, Chain, NameOrAddress, TxHash, H160, U256},
+    types::{Address, BlockNumber, Bytes, Chain, NameOrAddress, H160, U256},
 };
-use ethers_providers::Middleware;
+use ethers_providers::{Middleware, PendingTransaction};
 use std::{convert::TryFrom, sync::Arc};
 
 pub mod multicall_contract;
@@ -223,8 +223,7 @@ impl TryFrom<u8> for MulticallVersion {
 ///
 /// // `await`ing the `send` method waits for the transaction to be broadcast, which also
 /// // returns the transaction hash
-/// let tx_hash = multicall.send().await?;
-/// let _tx_receipt = PendingTransaction::new(tx_hash, &client).await?;
+/// let _tx_receipt = multicall.send().await?.await.expect("tx dropped");
 ///
 /// // you can also query ETH balances of multiple addresses
 /// let address_1 = "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa".parse::<Address>()?;
@@ -569,7 +568,7 @@ impl<M: Middleware> Multicall<M> {
     ///     .add_call(broadcast_1, false)
     ///     .add_call(broadcast_2, false);
     ///
-    /// let _tx_hash = multicall.send().await?;
+    /// let _tx_receipt = multicall.send().await?.await.expect("tx dropped");
     ///
     /// # let call_1 = contract.method::<_, String>("getValue", ())?;
     /// # let call_2 = contract.method::<_, Address>("lastSender", ())?;
@@ -735,7 +734,7 @@ impl<M: Middleware> Multicall<M> {
             v @ (MulticallVersion::Multicall2 | MulticallVersion::Multicall3) => {
                 let is_v2 = v == MulticallVersion::Multicall2;
                 let call = if is_v2 { self.as_try_aggregate() } else { self.as_aggregate_3() };
-                let return_data = call.call().await?;
+                let return_data = ContractCall::call(&call).await?;
                 self.calls
                     .iter()
                     .zip(return_data.into_iter())
@@ -789,7 +788,7 @@ impl<M: Middleware> Multicall<M> {
     }
 
     /// Signs and broadcasts a batch of transactions by using the Multicall contract as proxy,
-    /// returning the transaction hash once the transaction confirms.
+    /// returning the pending transaction.
     ///
     /// Note: this method will broadcast a transaction from an account, meaning it must have
     /// sufficient funds for gas and transaction value.
@@ -811,32 +810,18 @@ impl<M: Middleware> Multicall<M> {
     /// # Ok(())
     /// # }
     /// ```
-    pub async fn send(&self) -> Result<TxHash, M> {
-        // Broadcast transaction and return the transaction hash
-        // TODO: Can we make this return a PendingTransaction directly instead?
-        // Seems hard due to `returns a value referencing data owned by the current function`
-
-        // running clippy --fix on this throws E0597
-        #[allow(clippy::let_and_return)]
-        let tx_hash = match self.version {
-            MulticallVersion::Multicall => {
-                let call = self.as_aggregate();
-                let hash = *call.send().await?;
-                hash
-            }
-            MulticallVersion::Multicall2 => {
-                let call = self.as_try_aggregate();
-                let hash = *call.send().await?;
-                hash
-            }
-            MulticallVersion::Multicall3 => {
-                let call = self.as_aggregate_3_value();
-                let hash = *call.send().await?;
-                hash
-            }
+    pub async fn send(&self) -> Result<PendingTransaction<'_, M::Provider>, M> {
+        let tx = match self.version {
+            MulticallVersion::Multicall => self.as_aggregate().tx,
+            MulticallVersion::Multicall2 => self.as_try_aggregate().tx,
+            MulticallVersion::Multicall3 => self.as_aggregate_3_value().tx,
         };
 
-        Ok(tx_hash)
+        self.contract
+            .client_ref()
+            .send_transaction(tx, self.block.map(Into::into))
+            .await
+            .map_err(|e| MulticallError::ContractError(ContractError::MiddlewareError(e)))
     }
 
     /// v1

Diff for: ethers-contract/tests/it/contract.rs

@@ -491,8 +491,7 @@ mod eth_tests {
         multicall_send.clear_calls().add_call(broadcast, false).add_call(broadcast2, false);
 
         // broadcast the transaction and wait for it to be mined
-        let tx_hash = multicall_send.legacy().send().await.unwrap();
-        let _tx_receipt = PendingTransaction::new(tx_hash, client.provider()).await.unwrap();
+        let _tx_receipt = multicall_send.legacy().send().await.unwrap().await.unwrap();
 
         // Do another multicall to check the updated return values
         // The `getValue` calls should return the last value we set in the batched broadcast