feat: support no_std for alloy-genesis/alloy-serde (#320)

* feat: support no_std for alloy-genesis/alloy-serde

* remove unused file

* fmt

* fix for tests

* adjust a little

* clippy warnings

* clippy warnings

* use feature gate

* fix feature gate

* fmt

* Update Cargo.toml

* Update README.md

Co-authored-by: Oliver Nordbjerg <[email protected]>

---------

Co-authored-by: Matthias Seitz <[email protected]>
Co-authored-by: James Prestwich <[email protected]>
Co-authored-by: Oliver Nordbjerg <[email protected]>

Cargo.toml

@@ -94,7 +94,7 @@ thiserror-no-std = "2.0.2"
 url = "2.5"
 
 ## serde
-serde = { version = "1.0", features = ["derive"], default-features = false }
+serde = { version = "1.0", default-features = false, features = ["derive"] }
 serde_json = "1.0"
 
 ## misc-testing

README.md

@@ -101,7 +101,11 @@ contribution follows the linting rules and passes clippy.
 ## Note on `no_std`
 
 Because these crates are primarily json-rpc focused, we do not intend to support
-`no_std` for them at this time.
+`no_std` for most of them at this time. 
+The following crates support `no_std`:
+- alloy-eips
+- alloy-genesis
+- alloy-serde
 
 ## Credits
 

crates/genesis/Cargo.toml

@@ -20,3 +20,12 @@ serde.workspace = true
 
 [dev-dependencies]
 serde_json.workspace = true
+
+[features]
+default = ["std"]
+std = [
+    "alloy-primitives/std",
+    "alloy-serde/std",
+    # serde
+    "serde/std",
+]

crates/genesis/src/lib.rs

@@ -16,6 +16,11 @@
 #![cfg_attr(not(test), warn(unused_crate_dependencies))]
 #![deny(unused_must_use, rust_2018_idioms)]
 #![cfg_attr(docsrs, feature(doc_cfg, doc_auto_cfg))]
+#![cfg_attr(not(feature = "std"), no_std)]
+
+extern crate alloc;
+
+use alloc::collections::BTreeMap;
 
 use alloy_primitives::{Address, Bytes, B256, U256};
 use alloy_serde::{
@@ -24,7 +29,6 @@ use alloy_serde::{
     storage::deserialize_storage_map,
 };
 use serde::{Deserialize, Serialize};
-use std::collections::HashMap;
 
 /// The genesis block specification.
 #[derive(Clone, Debug, Default, Serialize, Deserialize, PartialEq, Eq)]
@@ -52,7 +56,7 @@ pub struct Genesis {
     /// The genesis header coinbase address.
     pub coinbase: Address,
     /// The initial state of accounts in the genesis block.
-    pub alloc: HashMap<Address, GenesisAccount>,
+    pub alloc: BTreeMap<Address, GenesisAccount>,
     // NOTE: the following fields:
     // * base_fee_per_gas
     // * excess_blob_gas
@@ -102,7 +106,7 @@ impl Genesis {
         };
 
         // fund account
-        let mut alloc = HashMap::new();
+        let mut alloc = BTreeMap::default();
         alloc.insert(
             signer_addr,
             GenesisAccount {
@@ -226,7 +230,7 @@ pub struct GenesisAccount {
         skip_serializing_if = "Option::is_none",
         deserialize_with = "deserialize_storage_map"
     )]
-    pub storage: Option<HashMap<B256, B256>>,
+    pub storage: Option<BTreeMap<B256, B256>>,
     /// The account's private key. Should only be used for testing.
     #[serde(rename = "secretKey", default, skip_serializing_if = "Option::is_none")]
     pub private_key: Option<B256>,
@@ -252,7 +256,7 @@ impl GenesisAccount {
     }
 
     /// Set the storage.
-    pub fn with_storage(mut self, storage: Option<HashMap<B256, B256>>) -> Self {
+    pub fn with_storage(mut self, storage: Option<BTreeMap<B256, B256>>) -> Self {
         self.storage = storage;
         self
     }
@@ -538,8 +542,9 @@ pub struct CliqueConfig {
 #[cfg(test)]
 mod tests {
     use super::*;
+    use alloc::vec;
     use alloy_primitives::hex;
-    use std::str::FromStr;
+    use core::str::FromStr;
 
     #[test]
     fn test_genesis() {
@@ -555,7 +560,7 @@ mod tests {
         let coinbase = hex!("265873b6faf3258b3ab0827805386a2a20ed040e").into();
         // create dummy account
         let first_address: Address = hex!("7618a8c597b89e01c66a1f662078992c52a30c9a").into();
-        let mut account = HashMap::default();
+        let mut account = BTreeMap::default();
         account.insert(first_address, GenesisAccount::default());
 
         // check values updated
@@ -587,18 +592,18 @@ mod tests {
             nonce: Some(1),
             balance: U256::from(1),
             code: Some(Bytes::from(b"code")),
-            storage: Some(HashMap::default()),
+            storage: Some(BTreeMap::default()),
             private_key: None,
         };
-        let mut updated_account = HashMap::default();
+        let mut updated_account = BTreeMap::default();
         updated_account.insert(same_address, new_alloc_account);
         let custom_genesis = custom_genesis.extend_accounts(updated_account.clone());
         assert_ne!(account, updated_account);
         assert_eq!(custom_genesis.alloc.len(), 1);
 
         // add second account
         let different_address = hex!("94e0681e3073dd71cec54b53afe988f39078fd1a").into();
-        let more_accounts = HashMap::from([(different_address, GenesisAccount::default())]);
+        let more_accounts = BTreeMap::from([(different_address, GenesisAccount::default())]);
         let custom_genesis = custom_genesis.extend_accounts(more_accounts);
         assert_eq!(custom_genesis.alloc.len(), 2);
 
@@ -619,7 +624,7 @@ mod tests {
         let code = Some(Bytes::from(b"code"));
         let root = hex!("9474ddfcea39c5a690d2744103e39d1ff1b03d18db10fc147d970ad24699395a").into();
         let value = hex!("58eb8294d9bb16832a9dabfcb270fff99ab8ee1d8764e4f3d9fdf59ec1dee469").into();
-        let mut map = HashMap::default();
+        let mut map = BTreeMap::default();
         map.insert(root, value);
         let storage = Some(map);
 
@@ -1054,7 +1059,7 @@ mod tests {
             .get(&Address::from_str("0000000000000000000000000000000000000314").unwrap())
             .expect("missing account for parsed genesis");
         let storage = alloc_entry.storage.as_ref().expect("missing storage for parsed genesis");
-        let expected_storage = HashMap::from_iter(vec![
+        let expected_storage = BTreeMap::from_iter(vec![
             (
                 B256::from_str(
                     "0x0000000000000000000000000000000000000000000000000000000000000000",
@@ -1162,7 +1167,7 @@ mod tests {
                 excess_blob_gas: None,
                 blob_gas_used: None,
                 number: None,
-                alloc: HashMap::from_iter(vec![
+                alloc: BTreeMap::from_iter(vec![
                 (
                     Address::from_str("0xdbdbdb2cbd23b783741e8d7fcf51e459b497e4a6").unwrap(),
                     GenesisAccount {
@@ -1190,7 +1195,7 @@ mod tests {
                         balance: U256::from_str("0x21").unwrap(),
                         nonce: None,
                         code: None,
-                        storage: Some(HashMap::from_iter(vec![
+                        storage: Some(BTreeMap::from_iter(vec![
                             (
 
     B256::from_str("0x0000000000000000000000000000000000000000000000000000000000000001").

crates/serde/Cargo.toml

@@ -12,11 +12,10 @@ repository.workspace = true
 exclude.workspace = true
 
 [dependencies]
-# ethereum
 alloy-primitives = { workspace = true, features = ["rlp", "serde"] }
-
-serde = { workspace = true, features = ["derive"] }
-serde_json.workspace = true
+# serde
+serde = { workspace = true }
+serde_json = { workspace = true, default-features = false, features = ["alloc"] }
 
 [dev-dependencies]
 alloy-primitives = { workspace = true, features = [
@@ -25,3 +24,12 @@ alloy-primitives = { workspace = true, features = [
   "serde",
   "arbitrary",
 ] }
+
+[features]
+default = ["std"]
+std = [
+  "alloy-primitives/std",
+  # serde
+  "serde/std",
+  "serde_json/std",
+]

crates/serde/src/json_u256.rs

@@ -1,11 +1,16 @@
 //! Json U256 serde helpers.
+
+#[cfg(not(feature = "std"))]
+use alloc::string::String;
+use alloc::{fmt, format};
+use core::str::FromStr;
+
 use alloy_primitives::U256;
 use serde::{
     de::{Error, Visitor},
     Deserialize, Deserializer, Serialize, Serializer,
 };
 use serde_json::Value;
-use std::{fmt, str::FromStr};
 
 /// Wrapper around primitive U256 type that also supports deserializing numbers
 #[derive(Default, Debug, PartialEq, Eq, PartialOrd, Ord, Hash, Clone, Copy)]
@@ -175,6 +180,8 @@ where
 #[cfg(test)]
 mod test {
     use super::JsonU256;
+    #[cfg(not(feature = "std"))]
+    use alloc::{vec, vec::Vec};
     use alloy_primitives::U256;
     use serde::{Deserialize, Serialize};
 

crates/serde/src/lib.rs

@@ -16,20 +16,25 @@
 #![cfg_attr(not(test), warn(unused_crate_dependencies))]
 #![deny(unused_must_use, rust_2018_idioms)]
 #![cfg_attr(docsrs, feature(doc_cfg, doc_auto_cfg))]
+#![cfg_attr(not(feature = "std"), no_std)]
+
+extern crate alloc;
+
+use alloc::format;
 
 use alloy_primitives::B256;
 use serde::Serializer;
 
 pub mod json_u256;
-pub use json_u256::JsonU256;
+pub use self::json_u256::JsonU256;
 
 /// Helpers for dealing with numbers.
 pub mod num;
-pub use num::*;
+pub use self::num::*;
 
 /// Storage related helpers.
 pub mod storage;
-pub use storage::JsonStorageKey;
+pub use self::storage::JsonStorageKey;
 
 /// Serialize a byte vec as a hex string _without_ the "0x" prefix.
 ///

crates/serde/src/num.rs

@@ -1,8 +1,11 @@
 //! Numeric serde helpers.
 
+#[cfg(not(feature = "std"))]
+use alloc::string::ToString;
+use core::str::FromStr;
+
 use alloy_primitives::{U256, U64};
 use serde::{de, Deserialize, Deserializer, Serialize};
-use std::str::FromStr;
 
 /// A `u64` wrapper type that deserializes from hex or a u64 and serializes as hex.
 ///

crates/serde/src/storage.rs

@@ -1,6 +1,9 @@
+#[cfg(not(feature = "std"))]
+use alloc::string::{String, ToString};
+use alloc::{collections::BTreeMap, fmt::Write};
+
 use alloy_primitives::{Bytes, B256, U256};
 use serde::{Deserialize, Deserializer, Serialize};
-use std::{collections::HashMap, fmt::Write};
 
 /// A storage key type that can be serialized to and from a hex string up to 32 bytes. Used for
 /// `eth_getStorageAt` and `eth_getProof` RPCs.
@@ -87,15 +90,15 @@ where
 /// ```
 pub fn deserialize_storage_map<'de, D>(
     deserializer: D,
-) -> Result<Option<HashMap<B256, B256>>, D::Error>
+) -> Result<Option<BTreeMap<B256, B256>>, D::Error>
 where
     D: Deserializer<'de>,
 {
-    let map = Option::<HashMap<Bytes, Bytes>>::deserialize(deserializer)?;
+    let map = Option::<BTreeMap<Bytes, Bytes>>::deserialize(deserializer)?;
     match map {
-        Some(mut map) => {
-            let mut res_map = HashMap::with_capacity(map.len());
-            for (k, v) in map.drain() {
+        Some(map) => {
+            let mut res_map = BTreeMap::new();
+            for (k, v) in map {
                 let k_deserialized = from_bytes_to_b256::<'de, D>(k)?;
                 let v_deserialized = from_bytes_to_b256::<'de, D>(v)?;
                 res_map.insert(k_deserialized, v_deserialized);