From e6995e5cdf3099fd1d492e63d599d11cae77b142 Mon Sep 17 00:00:00 2001
From: grantkee <49913008+grantkee@users.noreply.github.com>
Date: Thu, 2 Nov 2023 21:58:29 -0500
Subject: [PATCH] Parse Genesis Value from Memory (#5238)

---
 bin/reth/src/args/utils.rs          | 120 ++++++++++++++++++++++++++--
 crates/primitives/src/chain/spec.rs |  68 +++++++++++++++-
 crates/primitives/src/lib.rs        |   2 +-
 3 files changed, 180 insertions(+), 10 deletions(-)

diff --git a/bin/reth/src/args/utils.rs b/bin/reth/src/args/utils.rs
index b0035f1c64..0f9ef5c6bb 100644
--- a/bin/reth/src/args/utils.rs
+++ b/bin/reth/src/args/utils.rs
@@ -34,8 +34,11 @@ pub fn chain_spec_value_parser(s: &str) -> eyre::Result<Arc<ChainSpec>, eyre::Er
     })
 }
 
-/// Clap value parser for [ChainSpec]s that takes either a built-in genesis format or the path
-/// to a custom one.
+/// Clap value parser for [ChainSpec]s.
+///
+/// The value parser matches either a known chain, the path
+/// to a json file, or a json formatted string in-memory. The json can be either
+/// a serialized [ChainSpec] or Genesis struct.
 pub fn genesis_value_parser(s: &str) -> eyre::Result<Arc<ChainSpec>, eyre::Error> {
     Ok(match s {
         "mainnet" => MAINNET.clone(),
@@ -44,8 +47,21 @@ pub fn genesis_value_parser(s: &str) -> eyre::Result<Arc<ChainSpec>, eyre::Error
         "holesky" => HOLESKY.clone(),
         "dev" => DEV.clone(),
         _ => {
-            let raw = fs::read_to_string(PathBuf::from(shellexpand::full(s)?.into_owned()))?;
-            let genesis: AllGenesisFormats = serde_json::from_str(&raw)?;
+            // both serialized Genesis and ChainSpec structs supported
+            let genesis: AllGenesisFormats =
+                // try to read json from path first
+                match fs::read_to_string(PathBuf::from(shellexpand::full(s)?.into_owned())) {
+                    Ok(raw) => serde_json::from_str(&raw)?,
+                    Err(io_err) => {
+                        // valid json may start with "\n", but must contain "{"
+                        if s.contains('{') {
+                            serde_json::from_str(s)?
+                        } else {
+                            return Err(io_err.into()) // assume invalid path
+                        }
+                    }
+                };
+
             Arc::new(genesis.into())
         }
     })
@@ -108,16 +124,110 @@ pub fn parse_socket_address(value: &str) -> eyre::Result<SocketAddr, SocketAddre
 mod tests {
     use super::*;
     use proptest::prelude::Rng;
+    use reth_primitives::{
+        hex, Address, ChainConfig, ChainSpecBuilder, Genesis, GenesisAccount, U256,
+    };
     use secp256k1::rand::thread_rng;
+    use std::collections::HashMap;
 
     #[test]
-    fn parse_chain_spec() {
+    fn parse_known_chain_spec() {
         for chain in ["mainnet", "sepolia", "goerli", "holesky"] {
             chain_spec_value_parser(chain).unwrap();
             genesis_value_parser(chain).unwrap();
         }
     }
 
+    #[test]
+    fn parse_chain_spec_from_memory() {
+        let custom_genesis_from_json = r#"
+{
+    "nonce": "0x0",
+    "timestamp": "0x653FEE9E",
+    "gasLimit": "0x1388",
+    "difficulty": "0x0",
+    "mixHash": "0x0000000000000000000000000000000000000000000000000000000000000000",
+    "coinbase": "0x0000000000000000000000000000000000000000",
+    "alloc": {
+        "0x6Be02d1d3665660d22FF9624b7BE0551ee1Ac91b": {
+            "balance": "0x21"
+        }
+    },
+    "number": "0x0",
+    "gasUsed": "0x0",
+    "parentHash": "0x0000000000000000000000000000000000000000000000000000000000000000",
+    "config": {
+        "chainId": 2600,
+        "homesteadBlock": 0,
+        "eip150Block": 0,
+        "eip155Block": 0,
+        "eip158Block": 0,
+        "byzantiumBlock": 0,
+        "constantinopleBlock": 0,
+        "petersburgBlock": 0,
+        "istanbulBlock": 0,
+        "berlinBlock": 0,
+        "londonBlock": 0,
+        "terminalTotalDifficulty": 0,
+        "terminalTotalDifficultyPassed": true,
+        "shanghaiTime": 0
+    }
+}
+"#;
+
+        let chain_from_json = genesis_value_parser(custom_genesis_from_json).unwrap();
+
+        // using structs
+        let config = ChainConfig {
+            chain_id: 2600,
+            homestead_block: Some(0),
+            eip150_block: Some(0),
+            eip155_block: Some(0),
+            eip158_block: Some(0),
+            byzantium_block: Some(0),
+            constantinople_block: Some(0),
+            petersburg_block: Some(0),
+            istanbul_block: Some(0),
+            berlin_block: Some(0),
+            london_block: Some(0),
+            shanghai_time: Some(0),
+            terminal_total_difficulty: Some(U256::ZERO),
+            terminal_total_difficulty_passed: true,
+            ..Default::default()
+        };
+        let genesis = Genesis {
+            config,
+            nonce: 0,
+            timestamp: 1698688670,
+            gas_limit: 5000,
+            difficulty: U256::ZERO,
+            mix_hash: B256::ZERO,
+            coinbase: Address::ZERO,
+            ..Default::default()
+        };
+
+        // seed accounts after genesis struct created
+        let address = hex!("6Be02d1d3665660d22FF9624b7BE0551ee1Ac91b").into();
+        let account = GenesisAccount::default().with_balance(U256::from(33));
+        let genesis = genesis.extend_accounts(HashMap::from([(address, account)]));
+
+        let custom_genesis_from_struct = serde_json::to_string(&genesis).unwrap();
+        let chain_from_struct = genesis_value_parser(&custom_genesis_from_struct).unwrap();
+        assert_eq!(chain_from_json.genesis(), chain_from_struct.genesis());
+
+        // chain spec
+        let chain_spec = ChainSpecBuilder::default()
+            .chain(2600.into())
+            .genesis(genesis)
+            .cancun_activated()
+            .build();
+
+        let chain_spec_json = serde_json::to_string(&chain_spec).unwrap();
+        let custom_genesis_from_spec = genesis_value_parser(&chain_spec_json).unwrap();
+
+        assert_eq!(custom_genesis_from_spec.chain(), chain_from_struct.chain());
+    }
+
     #[test]
     fn parse_socket_addresses() {
         for value in ["localhost:9000", ":9000", "9000"] {
diff --git a/crates/primitives/src/chain/spec.rs b/crates/primitives/src/chain/spec.rs
index 979345ca13..81cce105c4 100644
--- a/crates/primitives/src/chain/spec.rs
+++ b/crates/primitives/src/chain/spec.rs
@@ -708,10 +708,10 @@ impl ForkTimestamps {
 #[derive(Debug, Clone, Deserialize, Serialize)]
 #[serde(untagged)]
 pub enum AllGenesisFormats {
-    /// The geth genesis format
-    Geth(Genesis),
     /// The reth genesis format
     Reth(ChainSpec),
+    /// The geth genesis format
+    Geth(Genesis),
 }
 
 impl From<Genesis> for AllGenesisFormats {
@@ -1189,10 +1189,13 @@ impl DepositContract {
 #[cfg(test)]
 mod tests {
     use super::*;
-    use crate::{b256, hex, NamedChain, B256, DEV, GOERLI, HOLESKY, MAINNET, SEPOLIA, U256};
+    use crate::{
+        b256, hex, ChainConfig, GenesisAccount, NamedChain, B256, DEV, GOERLI, HOLESKY, MAINNET,
+        SEPOLIA, U256,
+    };
     use alloy_rlp::Encodable;
     use bytes::BytesMut;
-    use std::str::FromStr;
+    use std::{collections::HashMap, str::FromStr};
 
     fn test_fork_ids(spec: &ChainSpec, cases: &[(Head, ForkId)]) {
         for (block, expected_id) in cases {
@@ -2293,4 +2296,61 @@ Post-merge hard forks (timestamp based):
             .fork(Hardfork::Paris)
             .active_at_ttd(HOLESKY.genesis.difficulty, HOLESKY.genesis.difficulty));
     }
+
+    #[test]
+    fn test_all_genesis_formats_deserialization() {
+        // custom genesis with chain config
+        let config = ChainConfig {
+            chain_id: 2600,
+            homestead_block: Some(0),
+            eip150_block: Some(0),
+            eip155_block: Some(0),
+            eip158_block: Some(0),
+            byzantium_block: Some(0),
+            constantinople_block: Some(0),
+            petersburg_block: Some(0),
+            istanbul_block: Some(0),
+            berlin_block: Some(0),
+            london_block: Some(0),
+            shanghai_time: Some(0),
+            terminal_total_difficulty: Some(U256::ZERO),
+            terminal_total_difficulty_passed: true,
+            ..Default::default()
+        };
+        // genesis
+        let genesis = Genesis {
+            config,
+            nonce: 0,
+            timestamp: 1698688670,
+            gas_limit: 5000,
+            difficulty: U256::ZERO,
+            mix_hash: B256::ZERO,
+            coinbase: Address::ZERO,
+            ..Default::default()
+        };
+
+        // seed accounts after genesis struct created
+        let address = hex!("6Be02d1d3665660d22FF9624b7BE0551ee1Ac91b").into();
+        let account = GenesisAccount::default().with_balance(U256::from(33));
+        let genesis = genesis.extend_accounts(HashMap::from([(address, account)]));
+
+        // ensure genesis is deserialized correctly
+        let serialized_genesis = serde_json::to_string(&genesis).unwrap();
+        let deserialized_genesis: AllGenesisFormats =
+            serde_json::from_str(&serialized_genesis).unwrap();
+        assert!(matches!(deserialized_genesis, AllGenesisFormats::Geth(_)));
+
+        // build chain
+        let chain_spec = ChainSpecBuilder::default()
+            .chain(2600.into())
+            .genesis(genesis)
+            .cancun_activated()
+            .build();
+
+        // ensure chain spec is deserialized correctly
+        let serialized_chain_spec = serde_json::to_string(&chain_spec).unwrap();
+        let deserialized_chain_spec: AllGenesisFormats =
+            serde_json::from_str(&serialized_chain_spec).unwrap();
+        assert!(matches!(deserialized_chain_spec, AllGenesisFormats::Reth(_)))
+    }
 }
diff --git a/crates/primitives/src/lib.rs b/crates/primitives/src/lib.rs
index 379ace2dc4..36fba28daa 100644
--- a/crates/primitives/src/lib.rs
+++ b/crates/primitives/src/lib.rs
@@ -67,7 +67,7 @@ pub use constants::{
 #[cfg(feature = "c-kzg")]
 pub use eip4844::{calculate_excess_blob_gas, kzg_to_versioned_hash};
 pub use forkid::{ForkFilter, ForkHash, ForkId, ForkTransition, ValidationError};
-pub use genesis::{Genesis, GenesisAccount};
+pub use genesis::{ChainConfig, Genesis, GenesisAccount};
 pub use hardfork::Hardfork;
 pub use header::{Head, Header, HeadersDirection, SealedHeader};
 pub use integer_list::IntegerList;