fix(providers): QuorumProvider zero-parameter json Value handling (#1613)

* Correction to QuorumProvider json Value handling with zero-parameter cases

* Update to properly pass through when no parameters are specified

ethers-providers/src/transports/mock.rs

@@ -10,10 +10,19 @@ use std::{
 };
 use thiserror::Error;
 
+/// Helper type that can be used to pass through the `params` value.
+/// This is necessary because the wrapper provider is supposed to skip the `params` if it's of
+/// size 0, see `crate::transports::common::Request`
+#[derive(Debug)]
+enum MockParams {
+    Value(Value),
+    Zst
+}
+
 #[derive(Clone, Debug)]
 /// Mock transport used in test environments.
 pub struct MockProvider {
-    requests: Arc<Mutex<VecDeque<(String, Value)>>>,
+    requests: Arc<Mutex<VecDeque<(String, MockParams)>>>,
     responses: Arc<Mutex<VecDeque<Value>>>,
 }
 
@@ -28,14 +37,19 @@ impl Default for MockProvider {
 impl JsonRpcClient for MockProvider {
     type Error = MockError;
 
-    /// Pushes the `(method, input)` to the back of the `requests` queue,
+    /// Pushes the `(method, params)` to the back of the `requests` queue,
     /// pops the responses from the back of the `responses` queue
     async fn request<T: Serialize + Send + Sync, R: DeserializeOwned>(
         &self,
         method: &str,
-        input: T,
+        params: T,
     ) -> Result<R, MockError> {
-        self.requests.lock().unwrap().push_back((method.to_owned(), serde_json::to_value(input)?));
+        let params = if std::mem::size_of::<T>() == 0 {
+            MockParams::Zst
+        } else {
+            MockParams::Value(serde_json::to_value(params)?)
+        };
+        self.requests.lock().unwrap().push_back((method.to_owned(), params));
         let mut data = self.responses.lock().unwrap();
         let element = data.pop_back().ok_or(MockError::EmptyResponses)?;
         let res: R = serde_json::from_value(element)?;
@@ -53,7 +67,15 @@ impl MockProvider {
     ) -> Result<(), MockError> {
         let (m, inp) = self.requests.lock().unwrap().pop_front().ok_or(MockError::EmptyRequests)?;
         assert_eq!(m, method);
+        assert!(!matches!(inp, MockParams::Value(serde_json::Value::Null)));
+        if std::mem::size_of::<T>() == 0 {
+            assert!(matches!(inp, MockParams::Zst));
+        } else if let MockParams::Value(inp) = inp {
             assert_eq!(serde_json::to_value(data).expect("could not serialize data"), inp);
+        } else {
+            unreachable!("Zero sized types must be denoted with MockParams::Zst")
+        }
+
         Ok(())
     }
 

ethers-providers/src/transports/quorum.rs

@@ -1,5 +1,4 @@
 use std::{
-    fmt,
     fmt::Debug,
     future::Future,
     pin::Pin,
@@ -166,7 +165,7 @@ impl<T: JsonRpcClientWrapper> QuorumProvider<T> {
     /// This is the minimum of all provider's block numbers
     async fn get_minimum_block_number(&self) -> Result<U64, ProviderError> {
         let mut numbers = join_all(self.providers.iter().map(|provider| async move {
-            let block = provider.inner.request("eth_blockNumber", serde_json::json!(())).await?;
+            let block = provider.inner.request("eth_blockNumber", QuorumParams::Zst).await?;
             serde_json::from_value::<U64>(block).map_err(ProviderError::from)
         }))
         .await
@@ -181,7 +180,13 @@ impl<T: JsonRpcClientWrapper> QuorumProvider<T> {
     }
 
     /// Normalizes the request payload depending on the call
-    async fn normalize_request(&self, method: &str, params: &mut Value) {
+    async fn normalize_request(&self, method: &str, q_params: &mut QuorumParams) {
+        let params = if let QuorumParams::Value(v) = q_params {
+            v
+        } else {
+            // at this time no normalization is required for calls with zero parameters.
+            return
+        };
         match method {
             "eth_call" |
             "eth_createAccessList" |
@@ -364,8 +369,8 @@ impl From<QuorumError> for ProviderError {
 
 #[cfg_attr(target_arch = "wasm32", async_trait(?Send))]
 #[cfg_attr(not(target_arch = "wasm32"), async_trait)]
-pub trait JsonRpcClientWrapper: Send + Sync + fmt::Debug {
-    async fn request(&self, method: &str, params: Value) -> Result<Value, ProviderError>;
+pub trait JsonRpcClientWrapper: Send + Sync + Debug {
+    async fn request(&self, method: &str, params: QuorumParams) -> Result<Value, ProviderError>;
 }
 type NotificationStream =
     Box<dyn futures_core::Stream<Item = Box<RawValue>> + Send + Unpin + 'static>;
@@ -381,14 +386,20 @@ pub trait PubsubClientWrapper: JsonRpcClientWrapper {
 #[cfg_attr(target_arch = "wasm32", async_trait(?Send))]
 #[cfg_attr(not(target_arch = "wasm32"), async_trait)]
 impl<C: JsonRpcClient> JsonRpcClientWrapper for C {
-    async fn request(&self, method: &str, params: Value) -> Result<Value, ProviderError> {
-        Ok(JsonRpcClient::request(self, method, params).await.map_err(C::Error::into)?)
+    async fn request(&self, method: &str, params: QuorumParams) -> Result<Value, ProviderError> {
+        let fut = if let QuorumParams::Value(params) = params {
+            JsonRpcClient::request(self, method, params)
+        } else {
+            JsonRpcClient::request(self, method, ())
+        };
+
+        Ok(fut.await.map_err(C::Error::into)?)
     }
 }
 #[cfg_attr(target_arch = "wasm32", async_trait(?Send))]
 #[cfg_attr(not(target_arch = "wasm32"), async_trait)]
 impl JsonRpcClientWrapper for Box<dyn JsonRpcClientWrapper> {
-    async fn request(&self, method: &str, params: Value) -> Result<Value, ProviderError> {
+    async fn request(&self, method: &str, params: QuorumParams) -> Result<Value, ProviderError> {
         self.as_ref().request(method, params).await
     }
 }
@@ -396,7 +407,7 @@ impl JsonRpcClientWrapper for Box<dyn JsonRpcClientWrapper> {
 #[cfg_attr(target_arch = "wasm32", async_trait(?Send))]
 #[cfg_attr(not(target_arch = "wasm32"), async_trait)]
 impl JsonRpcClientWrapper for Box<dyn PubsubClientWrapper> {
-    async fn request(&self, method: &str, params: Value) -> Result<Value, ProviderError> {
+    async fn request(&self, method: &str, params: QuorumParams) -> Result<Value, ProviderError> {
         self.as_ref().request(method, params).await
     }
 }
@@ -437,7 +448,12 @@ where
         method: &str,
         params: T,
     ) -> Result<R, Self::Error> {
-        let mut params = serde_json::to_value(params)?;
+        let mut params = if std::mem::size_of::<T>() == 0 {
+            // we don't want `()` to become `"null"`.
+            QuorumParams::Zst
+        } else {
+            QuorumParams::Value(serde_json::to_value(params)?)
+        };
         self.normalize_request(method, &mut params).await;
 
         let requests = self
@@ -556,6 +572,15 @@ where
     }
 }
 
+/// Helper type that can be used to pass through the `params` value.
+/// This is necessary because the wrapper provider is supposed to skip the `params` if it's of
+/// size 0, see `crate::transports::common::Request`
+#[derive(Clone)]
+pub enum QuorumParams {
+    Value(Value),
+    Zst
+}
+
 #[cfg(test)]
 #[cfg(not(target_arch = "wasm32"))]
 mod tests {