Remove Index type from Config trait (#1074)

* remove config, doc tests are expected to fail (book not adjusted yet)

* make doc tests pass

* Prevent bug when reusing type ids in hashing (#1075)

* practice TDD

* implement a hashmap 2-phases approach

* use nicer types

* add test for cache filling

* adjust test

---------

Co-authored-by: James Wilson <james@jsdw.me>

* remove the unnecessary intos

---------

Co-authored-by: James Wilson <james@jsdw.me>

subxt/src/config/extrinsic_params.rs

@@ -17,7 +17,7 @@ use serde::{Deserialize, Serialize};
 /// "additional" parameters that are signed and used in transactions.
 /// see [`BaseExtrinsicParams`] for an implementation that is compatible with
 /// a Polkadot node.
-pub trait ExtrinsicParams<Index, Hash>: Debug + 'static {
+pub trait ExtrinsicParams<Hash>: Debug + 'static {
     /// These parameters can be provided to the constructor along with
     /// some default parameters that `subxt` understands, in order to
     /// help construct your [`ExtrinsicParams`] object.
@@ -27,7 +27,7 @@ pub trait ExtrinsicParams<Index, Hash>: Debug + 'static {
     fn new(
         spec_version: u32,
         tx_version: u32,
-        nonce: Index,
+        nonce: u64,
         genesis_hash: Hash,
         other_params: Self::OtherParams,
     ) -> Self;
@@ -58,7 +58,7 @@ pub trait ExtrinsicParams<Index, Hash>: Debug + 'static {
 #[derivative(Debug(bound = "Tip: Debug"))]
 pub struct BaseExtrinsicParams<T: Config, Tip: Debug> {
     era: Era,
-    nonce: T::Index,
+    nonce: u64,
     tip: Tip,
     spec_version: u32,
     transaction_version: u32,
@@ -122,7 +122,7 @@ impl<T: Config, Tip: Default> Default for BaseExtrinsicParamsBuilder<T, Tip> {
     }
 }
 
-impl<T: Config, Tip: Debug + Encode + 'static> ExtrinsicParams<T::Index, T::Hash>
+impl<T: Config, Tip: Debug + Encode + 'static> ExtrinsicParams<T::Hash>
     for BaseExtrinsicParams<T, Tip>
 {
     type OtherParams = BaseExtrinsicParamsBuilder<T, Tip>;
@@ -131,7 +131,7 @@ impl<T: Config, Tip: Debug + Encode + 'static> ExtrinsicParams<T::Index, T::Hash
         // Provided from subxt client:
         spec_version: u32,
         transaction_version: u32,
-        nonce: T::Index,
+        nonce: u64,
         genesis_hash: T::Hash,
         // Provided externally:
         other_params: Self::OtherParams,
@@ -149,7 +149,7 @@ impl<T: Config, Tip: Debug + Encode + 'static> ExtrinsicParams<T::Index, T::Hash
     }
 
     fn encode_extra_to(&self, v: &mut Vec<u8>) {
-        let nonce: u64 = self.nonce.into();
+        let nonce: u64 = self.nonce;
         let tip = Encoded(self.tip.encode());
         (self.era, Compact(nonce), tip).encode_to(v);
     }

subxt/src/config/mod.rs

@@ -25,10 +25,6 @@ pub use substrate::SubstrateConfig;
 // automatically applies a 'static bound to all generic types (including this one),
 // and so until that is resolved, we'll keep the (easy to satisfy) constraint here.
 pub trait Config: 'static {
-    /// Account index (aka nonce) type. This stores the number of previous
-    /// transactions associated with a sender account.
-    type Index: Debug + Copy + Decode + Into<u64>;
-
     /// The output of the `Hasher` function.
     type Hash: Debug
         + Copy
@@ -57,7 +53,7 @@ pub trait Config: 'static {
     type Header: Debug + Header<Hasher = Self::Hasher> + Sync + Send + DeserializeOwned;
 
     /// This type defines the extrinsic extra and additional parameters.
-    type ExtrinsicParams: extrinsic_params::ExtrinsicParams<Self::Index, Self::Hash>;
+    type ExtrinsicParams: extrinsic_params::ExtrinsicParams<Self::Hash>;
 }
 
 /// This represents the hasher used by a node to hash things like block headers
@@ -95,14 +91,13 @@ pub trait Header: Sized + Encode {
 /// Take a type implementing [`Config`] (eg [`SubstrateConfig`]), and some type which describes the
 /// additional and extra parameters to pass to an extrinsic (see [`ExtrinsicParams`]),
 /// and returns a type implementing [`Config`] with those new [`ExtrinsicParams`].
-pub struct WithExtrinsicParams<T: Config, E: extrinsic_params::ExtrinsicParams<T::Index, T::Hash>> {
+pub struct WithExtrinsicParams<T: Config, E: extrinsic_params::ExtrinsicParams<T::Hash>> {
     _marker: std::marker::PhantomData<(T, E)>,
 }
 
-impl<T: Config, E: extrinsic_params::ExtrinsicParams<T::Index, T::Hash>> Config
+impl<T: Config, E: extrinsic_params::ExtrinsicParams<T::Hash>> Config
     for WithExtrinsicParams<T, E>
 {
-    type Index = T::Index;
     type Hash = T::Hash;
     type AccountId = T::AccountId;
     type Address = T::Address;

subxt/src/config/polkadot.rs

@@ -18,7 +18,6 @@ pub use primitive_types::{H256, U256};
 pub enum PolkadotConfig {}
 
 impl Config for PolkadotConfig {
-    type Index = <SubstrateConfig as Config>::Index;
     type Hash = <SubstrateConfig as Config>::Hash;
     type AccountId = <SubstrateConfig as Config>::AccountId;
     type Address = MultiAddress<Self::AccountId, ()>;

subxt/src/config/substrate.rs

@@ -20,7 +20,6 @@ pub use primitive_types::{H256, U256};
 pub enum SubstrateConfig {}
 
 impl Config for SubstrateConfig {
-    type Index = u32;
     type Hash = H256;
     type AccountId = AccountId32;
     type Address = MultiAddress<Self::AccountId, u32>;