Merge bitcoindevkit/bdk#831: Don't default to use async/await on wasm32

32912eaa05fd3bb4fa1577ca413dcedf909544d9 Don't default to use `async`/`await` on `wasm32` (Elias Rohrer)

Pull request description:

  ### Description

  We don't automatically want to make the interface `async` based on the used architecture, but now require the user to explicitly set the `async-interface` feature.

  #### All Submissions:

  * [x] I've signed all my commits
  * [x] I followed the [contribution guidelines](https://github.com/bitcoindevkit/bdk/blob/master/CONTRIBUTING.md)
  * [x] I ran `cargo fmt` and `cargo clippy` before committing

ACKs for top commit:
  notmandatory:
    ACK 32912eaa05fd3bb4fa1577ca413dcedf909544d9

Tree-SHA512: 41a8f3ab29508a359a8c0d96994e4fa97e52c15e8b8003c1988bcfe036cafa81d6210d446ed825672ce52aff684ebb328dc61b8ae3d25cda6f51a3cae838de58

.github/workflows/cont_integration.yml

@@ -154,7 +154,7 @@ jobs:
       - name: Update toolchain
         run: rustup update
       - name: Check
-        run: cargo check --target wasm32-unknown-unknown --features use-esplora-async,dev-getrandom-wasm --no-default-features
+        run: cargo check --target wasm32-unknown-unknown --features async-interface,use-esplora-async,dev-getrandom-wasm --no-default-features
 
   fmt:
     name: Rust fmt

macros/src/lib.rs

@@ -19,7 +19,7 @@ use syn::{parse, ImplItemMethod, ItemImpl, ItemTrait, Token};
 
 fn add_async_trait(mut parsed: ItemTrait) -> TokenStream {
     let output = quote! {
-        #[cfg(all(not(target_arch = "wasm32"), not(feature = "async-interface")))]
+        #[cfg(not(feature = "async-interface"))]
         #parsed
     };
 
@@ -32,7 +32,7 @@ fn add_async_trait(mut parsed: ItemTrait) -> TokenStream {
     let output = quote! {
         #output
 
-        #[cfg(any(target_arch = "wasm32", feature = "async-interface"))]
+        #[cfg(feature = "async-interface")]
         #[async_trait(?Send)]
         #parsed
     };
@@ -42,7 +42,7 @@ fn add_async_trait(mut parsed: ItemTrait) -> TokenStream {
 
 fn add_async_method(mut parsed: ImplItemMethod) -> TokenStream {
     let output = quote! {
-        #[cfg(all(not(target_arch = "wasm32"), not(feature = "async-interface")))]
+        #[cfg(not(feature = "async-interface"))]
         #parsed
     };
 
@@ -51,7 +51,7 @@ fn add_async_method(mut parsed: ImplItemMethod) -> TokenStream {
     let output = quote! {
         #output
 
-        #[cfg(any(target_arch = "wasm32", feature = "async-interface"))]
+        #[cfg(feature = "async-interface")]
         #parsed
     };
 
@@ -60,7 +60,7 @@ fn add_async_method(mut parsed: ImplItemMethod) -> TokenStream {
 
 fn add_async_impl_trait(mut parsed: ItemImpl) -> TokenStream {
     let output = quote! {
-        #[cfg(all(not(target_arch = "wasm32"), not(feature = "async-interface")))]
+        #[cfg(not(feature = "async-interface"))]
         #parsed
     };
 
@@ -73,7 +73,7 @@ fn add_async_impl_trait(mut parsed: ItemImpl) -> TokenStream {
     let output = quote! {
         #output
 
-        #[cfg(any(target_arch = "wasm32", feature = "async-interface"))]
+        #[cfg(feature = "async-interface")]
         #[async_trait(?Send)]
         #parsed
     };
@@ -81,7 +81,7 @@ fn add_async_impl_trait(mut parsed: ItemImpl) -> TokenStream {
     output.into()
 }
 
-/// Makes a method or every method of a trait "async" only if the target_arch is "wasm32"
+/// Makes a method or every method of a trait `async`, if the `async-interface` feature is enabled.
 ///
 /// Requires the `async-trait` crate as a dependency whenever this attribute is used on a trait
 /// definition or trait implementation.
@@ -101,18 +101,18 @@ pub fn maybe_async(_attr: TokenStream, item: TokenStream) -> TokenStream {
     }
 }
 
-/// Awaits if target_arch is "wasm32", does nothing otherwise
+/// Awaits, if the `async-interface` feature is enabled.
 #[proc_macro]
 pub fn maybe_await(expr: TokenStream) -> TokenStream {
     let expr: proc_macro2::TokenStream = expr.into();
     let quoted = quote! {
         {
-            #[cfg(all(not(target_arch = "wasm32"), not(feature = "async-interface")))]
+            #[cfg(not(feature = "async-interface"))]
             {
                 #expr
             }
 
-            #[cfg(any(target_arch = "wasm32", feature = "async-interface"))]
+            #[cfg(feature = "async-interface")]
             {
                 #expr.await
             }
@@ -122,20 +122,20 @@ pub fn maybe_await(expr: TokenStream) -> TokenStream {
     quoted.into()
 }
 
-/// Awaits if target_arch is "wasm32", uses `tokio::Runtime::block_on()` otherwise
+/// Awaits, if the `async-interface` feature is enabled, uses `tokio::Runtime::block_on()` otherwise
 ///
-/// Requires the `tokio` crate as a dependecy with `rt-core` or `rt-threaded` to build on non-wasm32 platforms.
+/// Requires the `tokio` crate as a dependecy with `rt-core` or `rt-threaded` to build.
 #[proc_macro]
 pub fn await_or_block(expr: TokenStream) -> TokenStream {
     let expr: proc_macro2::TokenStream = expr.into();
     let quoted = quote! {
         {
-            #[cfg(all(not(target_arch = "wasm32"), not(feature = "async-interface")))]
+            #[cfg(not(feature = "async-interface"))]
             {
                 tokio::runtime::Builder::new_current_thread().enable_all().build().unwrap().block_on(#expr)
             }
 
-            #[cfg(any(target_arch = "wasm32", feature = "async-interface"))]
+            #[cfg(feature = "async-interface")]
             {
                 #expr.await
             }

src/blockchain/mod.rs

@@ -249,11 +249,8 @@ pub trait BlockchainFactory {
     /// operations to build a blockchain for a given wallet, so if a wallet needs to be synced
     /// often it's recommended to use [`BlockchainFactory::build_for_wallet`] to reuse the same
     /// blockchain multiple times.
-    #[cfg(not(any(target_arch = "wasm32", feature = "async-interface")))]
-    #[cfg_attr(
-        docsrs,
-        doc(cfg(not(any(target_arch = "wasm32", feature = "async-interface"))))
-    )]
+    #[cfg(not(feature = "async-interface"))]
+    #[cfg_attr(docsrs, doc(cfg(not(feature = "async-interface"))))]
     fn sync_wallet<D: BatchDatabase>(
         &self,
         wallet: &Wallet<D>,

src/lib.rs

@@ -227,7 +227,7 @@ compile_error!(
 #[cfg(feature = "keys-bip39")]
 extern crate bip39;
 
-#[cfg(any(target_arch = "wasm32", feature = "async-interface"))]
+#[cfg(feature = "async-interface")]
 #[macro_use]
 extern crate async_trait;
 #[macro_use]