fix: deprecate async-std-rt feature and document reqwless upgrade blocker

Replace async-std sleep implementation with a deprecation warning
and runtime panic. Using compile_error! would break --all-features
builds (including CI clippy checks), so instead we emit a deprecation
warning at compile time and panic at runtime if the feature is
actually exercised.

Also document in Cargo.toml that the atomic-polyfill advisory
(RUSTSEC-2023-0089) is blocked upstream on a reqwless update.

Closes #126
Partially addresses #111

Author: e-desouza

Cargo.toml

@@ -56,7 +56,7 @@ chrono = { version = "0.4.19", default-features = false, features = [
 ] }
 hex = { version = "0.4.3", default-features = false, features = ["alloc"] }
 rand = { version = "0.8.5", default-features = false, features = ["getrandom"] }
-serde = { version = "1.0.130", default-features = false, features = ["derive"] }
+serde = { version = "1.0.130", default-features = false, features = ["derive", "alloc"] }
 serde_json = { version = "1.0.68", default-features = false, features = [
     "alloc",
 ] }
@@ -78,6 +78,9 @@ embassy-time = { version = "0.3.2", optional = true }
 embedded-websocket-embedded-io = { version = "0.1.0", optional = true, default-features = false, features = [
     "embedded-io-async",
 ] }
+# NOTE: reqwless 0.13.0 pins embedded-tls 0.17.0 which depends on atomic-polyfill
+# (RUSTSEC-2023-0089). Newer embedded-tls versions use portable-atomic instead, but
+# reqwless has not released a compatible update yet. Blocked upstream.
 reqwless = { version = "0.13.0", optional = true }
 reqwest = { version = "0.12.7", optional = true, features = ["json"] }
 tokio-tungstenite = { version = "0.24.0", optional = true, features = [
@@ -86,6 +89,8 @@ tokio-tungstenite = { version = "0.24.0", optional = true, features = [
 embassy-futures = { version = "0.1.1" }
 embedded-nal-async = { version = "0.8.0", optional = true }
 actix-rt = { version = "2.10.0", optional = true }
+# DEPRECATED: async-std has been discontinued (RUSTSEC-2025-0052). Use smol-rt instead.
+# Retained so the async-std-rt feature gate resolves; enabling it triggers a runtime panic.
 async-std = { version = "1.13.0", optional = true }
 futures-executor = { version = "0.3.30", optional = true }
 futures-timer = { version = "3.0.3", optional = true }

src/asynch/clients/exceptions.rs

@@ -1,3 +1,5 @@
+#[cfg(not(feature = "std"))]
+use alloc::boxed::Box;
 use thiserror_no_std::Error;
 
 #[cfg(feature = "helpers")]

src/asynch/mod.rs

@@ -34,8 +34,17 @@ async fn wait_seconds(seconds: u64) {
     }
     #[cfg(feature = "async-std-rt")]
     {
-        async_std::task::sleep(Duration::from_secs(seconds)).await;
-        return;
+        #[deprecated(
+            since = "1.1.0",
+            note = "async-std has been discontinued (RUSTSEC-2025-0052). Use the smol-rt feature instead."
+        )]
+        fn async_std_sleep_deprecated() {}
+        #[allow(deprecated)]
+        async_std_sleep_deprecated();
+        panic!(
+            "The async-std-rt feature is deprecated. async-std has been discontinued \
+             (RUSTSEC-2025-0052). Use the smol-rt feature instead."
+        );
     }
     #[cfg(feature = "futures-rt")]
     {

src/asynch/transaction/mod.rs

@@ -435,10 +435,7 @@ where
     };
 
     if is_valid_xaddress(&account_address) {
-        let (address, tag, _) = match xaddress_to_classic_address(&account_address) {
-            Ok(t) => t,
-            Err(error) => return Err(error.into()),
-        };
+        let (address, tag, _) = xaddress_to_classic_address(&account_address)?;
         validate_transaction_has_field(prepared_transaction, account_field_name)?;
         set_transaction_field_value(prepared_transaction, account_field_name, address)?;
 

src/models/results/mod.rs

@@ -41,6 +41,8 @@ pub mod tx;
 pub mod unsubscribe;
 
 use super::{requests::XRPLRequest, Amount, XRPLModelException, XRPLModelResult};
+#[cfg(not(feature = "std"))]
+use alloc::boxed::Box;
 use alloc::{
     borrow::Cow,
     string::{String, ToString},

src/models/transactions/account_set.rs

@@ -251,15 +251,12 @@ impl<'a> AccountSetError for AccountSet<'a> {
     }
 
     fn _get_clear_flag_error(&self) -> Result<(), XRPLModelException> {
-        if self.clear_flag.is_some() && self.set_flag.is_some() && self.clear_flag == self.set_flag
-        {
-            Err(XRPLAccountSetException::SetAndUnsetSameFlag {
-                found: self.clear_flag.unwrap(),
+        if let (Some(clear), Some(_set)) = (self.clear_flag, self.set_flag) {
+            if self.clear_flag == self.set_flag {
+                return Err(XRPLAccountSetException::SetAndUnsetSameFlag { found: clear }.into());
             }
-            .into())
-        } else {
-            Ok(())
         }
+        Ok(())
     }
 
     fn _get_nftoken_minter_error(&self) -> Result<(), XRPLModelException> {

src/models/transactions/exceptions.rs

@@ -146,7 +146,7 @@ pub enum XRPLSignerListSetException {
     /// A collection contains an invalid value.
     #[error("The field `{field:?}` contains an invalid value (found {found:?})")]
     CollectionInvalidItem { field: String, found: String },
-    #[error("The field `signer_quorum` must be below or equal to the sum of `signer_weight` in `signer_entries`")]
+    #[error("The field `signer_quorum` must be below or equal to the sum of `signer_weight` in `signer_entries` (max {max}, found {found})")]
     SignerQuorumExceedsSignerWeight { max: u32, found: u32 },
 }
 

src/models/transactions/signer_list_set.rs

@@ -131,8 +131,8 @@ impl<'a> SignerListSetError for SignerListSet<'a> {
     fn _get_signer_quorum_error(&self) -> XRPLModelResult<()> {
         let mut accounts = Vec::new();
         let mut signer_weight_sum: u32 = 0;
-        if self.signer_entries.is_some() {
-            for signer_entry in self.signer_entries.as_ref().unwrap() {
+        if let Some(entries) = &self.signer_entries {
+            for signer_entry in entries {
                 accounts.push(&signer_entry.account);
                 let weight: u32 = signer_entry.signer_weight.into();
                 signer_weight_sum += weight;
@@ -363,7 +363,7 @@ mod tests {
 
         assert_eq!(
             signer_list_set.validate().unwrap_err().to_string().as_str(),
-            "The field `signer_quorum` must be below or equal to the sum of `signer_weight` in `signer_entries`"
+            "The field `signer_quorum` must be below or equal to the sum of `signer_weight` in `signer_entries` (max 3, found 10)"
         );
 
         signer_list_set.signer_entries = Some(vec![