Use Result<_, io::Error> over io::Result<_>

Personally I've always found the overload of a prelude enum to be
confusing, and never bothered to handle it properly in bindings as
a result. To avoid needing to do so now, we simply move the
newly-introduced `io::Result` usages over to
`Result<_, io::Error>`.

Author: TheBlueMatt

lightning/src/util/persist.rs

@@ -13,7 +13,7 @@ use bitcoin::hashes::hex::{FromHex, ToHex};
 use bitcoin::{BlockHash, Txid};
 
 use crate::io;
-use crate::prelude::{Vec, String};
+use crate::prelude::*;
 use crate::routing::scoring::WriteableScore;
 
 use crate::chain;
@@ -87,11 +87,11 @@ pub trait KVStore {
 	/// `namespace` and `sub_namespace`.
 	///
 	/// [`ErrorKind::NotFound`]: io::ErrorKind::NotFound
-	fn read(&self, namespace: &str, sub_namespace: &str, key: &str) -> io::Result<Vec<u8>>;
+	fn read(&self, namespace: &str, sub_namespace: &str, key: &str) -> Result<Vec<u8>, io::Error>;
 	/// Persists the given data under the given `key`.
 	///
 	/// Will create the given `namespace` and `sub_namespace` if not already present in the store.
-	fn write(&self, namespace: &str, sub_namespace: &str, key: &str, buf: &[u8]) -> io::Result<()>;
+	fn write(&self, namespace: &str, sub_namespace: &str, key: &str, buf: &[u8]) -> Result<(), io::Error>;
 	/// Removes any data that had previously been persisted under the given `key`.
 	///
 	/// If the `lazy` flag is set to `true`, the backend implementation might choose to lazily
@@ -106,12 +106,12 @@ pub trait KVStore {
 	///
 	/// Returns successfully if no data will be stored for the given `namespace`, `sub_namespace`, and
 	/// `key`, independently of whether it was present before its invokation or not.
-	fn remove(&self, namespace: &str, sub_namespace: &str, key: &str, lazy: bool) -> io::Result<()>;
+	fn remove(&self, namespace: &str, sub_namespace: &str, key: &str, lazy: bool) -> Result<(), io::Error>;
 	/// Returns a list of keys that are stored under the given `sub_namespace` in `namespace`.
 	///
 	/// Returns the keys in arbitrary order, so users requiring a particular order need to sort the
 	/// returned keys. Returns an empty list if `namespace` or `sub_namespace` is unknown.
-	fn list(&self, namespace: &str, sub_namespace: &str) -> io::Result<Vec<String>>;
+	fn list(&self, namespace: &str, sub_namespace: &str) -> Result<Vec<String>, io::Error>;
 }
 
 /// Trait that handles persisting a [`ChannelManager`], [`NetworkGraph`], and [`WriteableScore`] to disk.
@@ -205,7 +205,7 @@ impl<ChannelSigner: WriteableEcdsaChannelSigner, K: KVStore> Persist<ChannelSign
 /// Read previously persisted [`ChannelMonitor`]s from the store.
 pub fn read_channel_monitors<K: Deref, ES: Deref, SP: Deref>(
 	kv_store: K, entropy_source: ES, signer_provider: SP,
-) -> io::Result<Vec<(BlockHash, ChannelMonitor<<SP::Target as SignerProvider>::Signer>)>>
+) -> Result<Vec<(BlockHash, ChannelMonitor<<SP::Target as SignerProvider>::Signer>)>, io::Error>
 where
 	K::Target: KVStore,
 	ES::Target: EntropySource + Sized,