v0.50.0: Integrate frame-decode, redo storage APIs and break up Error. (#2100)

* WIP integrating new frame-decode and working out new storage APIS

* WIP: first pass adding new storage things to subxt-core

* Second pass over Address type and start impl in Subxt

* WIP new storage APIs

* WIP New storage APIs roughly completed, lots of errors still

* Remove PlainorMap enum; plain and map values now use same struct to simplify usage

* Begin 'fixing' errors

* WIP splitting errors and tidying payload/address traits

* Get subxt-core compiling

* Small fixes in subxt-core and remove metadata mod

* subxt-core: cargo check --all-targets passes

* Fix test

* WIP starting to update subxt from subxt-core changes

* WIP splitting up subxt errors into smaller variants

* WIP errors: add DispatchError errors

* Port new Storage APIs to subxt-core

* cargo check -p subxt passes

* Quick-fix errors in subxt-cli (explore subcommand)

* fmt

* Finish fixing codegen up and start fixing examples

* get Subxt examples compiling and bytes_at for constants

* Add some arcs to limit lifetimes in subxt/subxt-core storage APIs

* A little Arcing to allow more method chaining in Storage APIs, aligning with Subxt

* Update codegen test

* cargo check --all-targets passing

* cargo check --features 'unstable-light-client' passing

* clippy

* Remove unused dep in subxt

* use published frame-decode

* fix wasm-example

* Add new tx extension to fix daily tests

* Remove unused subxt_core::dynamic::DecodedValue type

* Update book to match changes

* Update docs to fix more broken bits

* Add missing docs

* fmt

* allow larger result errs for now

* Add missing alloc imports in subxt-core

* Fix doc tests and fix bug getting constant info

* Fix V14 -> Metadata transform for storage & constants

* Fix parachain example

* Fix FFI example

* BlockLength decodes t ostruct, not u128

* use fetch/iter shorthands rather than entry in most storage tests

* Fix some integration tests

* Fix Runtime codegen tests

* Expose the dynamic custom_value selecter and use in a UI test

* Update codegen metadata

* Tidy CLI storage query and support (str,str) as a storage address

* Add (str,str) as valid constant address too

* Show string tuple in constants example

* Via the magic of traits, avoid needing any clones of queries/addresses and accept references to them

* clippy

subxt/examples/storage_fetch_dynamic.rs

@@ -1,5 +1,6 @@
 #![allow(missing_docs)]
 use subxt::dynamic::{At, Value};
+use subxt::utils::AccountId32;
 use subxt::{OnlineClient, PolkadotConfig};
 use subxt_signer::sr25519::dev;
 
@@ -9,20 +10,25 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
     let api = OnlineClient::<PolkadotConfig>::new().await?;
 
     // Build a dynamic storage query to access account information.
-    let account = dev::alice().public_key();
-    let storage_query =
-        subxt::dynamic::storage("System", "Account", vec![Value::from_bytes(account)]);
+    // here, we assume that there is one value to provide at this entry
+    // to access a value; an AccountId32. In this example we don't know the
+    // return type and so we set it to `Value`, which anything can decode into.
+    let account: AccountId32 = dev::alice().public_key().into();
+    let storage_query = subxt::dynamic::storage::<(AccountId32,), Value>("System", "Account");
 
-    // Use that query to `fetch` a result. Because the query is dynamic, we don't know what the result
-    // type will be either, and so we get a type back that can be decoded into a dynamic Value type.
-    let result = api
-        .storage()
-        .at_latest()
+    // Use that query to access a storage entry, fetch a result and decode the value.
+    let client_at = api.storage().at_latest().await?;
+    let account_info = client_at
+        .entry(storage_query)?
+        .fetch((account,))
         .await?
-        .fetch(&storage_query)
-        .await?;
-    let value = result.unwrap().to_value()?;
+        .decode()?;
 
-    println!("Alice has free balance: {:?}", value.at("data").at("free"));
+    // With out `Value` type we can dig in to find what we want using the `At`
+    // trait and `.at()` method that this provides on the Value.
+    println!(
+        "Alice has free balance: {}",
+        account_info.at("data").at("free").unwrap()
+    );
     Ok(())
 }