world: single-source the ChainMethod read surface

crates/nexum-runtime/src/host/component/chain.rs

@@ -5,67 +5,13 @@ use std::future::Future;
 
 use alloy_chains::Chain;
 use alloy_rpc_types_eth::Filter;
-use strum::{EnumString, IntoStaticStr};
 
 use crate::host::provider_pool::{BlockStream, CanonicalLogStream, ProviderError, ProviderPool};
 
-/// The permitted JSON-RPC read surface as a closed type. Methods that
-/// sign or mutate node state have no variant, so a guest-supplied
-/// signing method (for example `eth_sign` or `eth_sendTransaction`)
-/// cannot be represented and never reaches the provider. This is the
-/// structural ceiling; an operator allowlist narrows within it and
-/// never widens it.
-#[derive(Debug, Clone, Copy, PartialEq, Eq, EnumString, IntoStaticStr)]
-#[non_exhaustive]
-pub enum ChainMethod {
-    #[strum(serialize = "eth_blockNumber")]
-    EthBlockNumber,
-    #[strum(serialize = "eth_call")]
-    EthCall,
-    #[strum(serialize = "eth_chainId")]
-    EthChainId,
-    #[strum(serialize = "eth_estimateGas")]
-    EthEstimateGas,
-    #[strum(serialize = "eth_feeHistory")]
-    EthFeeHistory,
-    #[strum(serialize = "eth_gasPrice")]
-    EthGasPrice,
-    #[strum(serialize = "eth_maxPriorityFeePerGas")]
-    EthMaxPriorityFeePerGas,
-    #[strum(serialize = "eth_getBalance")]
-    EthGetBalance,
-    #[strum(serialize = "eth_getBlockByHash")]
-    EthGetBlockByHash,
-    #[strum(serialize = "eth_getBlockByNumber")]
-    EthGetBlockByNumber,
-    #[strum(serialize = "eth_getBlockReceipts")]
-    EthGetBlockReceipts,
-    #[strum(serialize = "eth_getCode")]
-    EthGetCode,
-    #[strum(serialize = "eth_getLogs")]
-    EthGetLogs,
-    #[strum(serialize = "eth_getProof")]
-    EthGetProof,
-    #[strum(serialize = "eth_getStorageAt")]
-    EthGetStorageAt,
-    #[strum(serialize = "eth_getTransactionByHash")]
-    EthGetTransactionByHash,
-    #[strum(serialize = "eth_getTransactionCount")]
-    EthGetTransactionCount,
-    #[strum(serialize = "eth_getTransactionReceipt")]
-    EthGetTransactionReceipt,
-    #[strum(serialize = "net_version")]
-    NetVersion,
-}
-
-impl ChainMethod {
-    /// The wire method name forwarded to the provider. `&'static`
-    /// because the permitted set is closed, so the name drops straight
-    /// into alloy's `Cow<'static, str>` method slot without allocating.
-    pub fn as_str(self) -> &'static str {
-        self.into()
-    }
-}
+/// The read surface is defined once in `nexum-world`; host and guest
+/// re-export the same type, so the dispatch table and the guest
+/// allowlist cannot drift.
+pub use nexum_world::ChainMethod;
 
 /// Async chain backend. Methods mirror [`ProviderPool`] one-to-one;
 /// the `impl Future + Send` form bakes in the Send bound generic
@@ -134,51 +80,3 @@ impl ChainProvider for ProviderPool {
         ProviderPool::request(self, chain, method, params_json)
     }
 }
-
-#[cfg(test)]
-mod tests {
-    use super::ChainMethod;
-
-    #[test]
-    fn read_surface_methods_parse() {
-        for m in [
-            "eth_call",
-            "eth_blockNumber",
-            "eth_getBalance",
-            "eth_getLogs",
-            "eth_getTransactionReceipt",
-            "net_version",
-        ] {
-            assert!(ChainMethod::try_from(m).is_ok(), "{m} should parse");
-        }
-    }
-
-    #[test]
-    fn signing_and_mutating_methods_have_no_variant() {
-        for m in [
-            "eth_sign",
-            "eth_signTransaction",
-            "eth_sendTransaction",
-            "eth_sendRawTransaction",
-            "eth_accounts",
-            "personal_sign",
-            "personal_unlockAccount",
-            "admin_peers",
-            "debug_traceCall",
-            "miner_start",
-            "eth_notAMethod",
-            "",
-        ] {
-            assert!(ChainMethod::try_from(m).is_err(), "{m} must be rejected");
-        }
-    }
-
-    #[test]
-    fn as_str_round_trips_the_wire_name() {
-        assert_eq!(ChainMethod::EthCall.as_str(), "eth_call");
-        assert_eq!(
-            ChainMethod::try_from(ChainMethod::EthGetBalance.as_str()).unwrap(),
-            ChainMethod::EthGetBalance,
-        );
-    }
-}

crates/nexum-sdk/Cargo.toml

@@ -23,6 +23,10 @@ stderr-echo = []
 # calls back into this crate (`bind_host_via_wit_bindgen!`, the host
 # trait seam, the tracing facade).
 nexum-module-macros = { path = "../nexum-module-macros" }
+# The single-source vocabularies: `ChainMethod` (re-exported as
+# `chain::ChainMethod`) and the fault labels. Its world-synthesis half
+# is unused here, so the guest links `toml` and never calls it.
+nexum-world = { path = "../nexum-world" }
 alloy-primitives.workspace = true
 # Typed EIP-155 chain id; already in the guest graph via alloy-provider.
 alloy-chains.workspace = true
@@ -62,8 +66,6 @@ proptest.workspace = true
 # The keeper never touches the orderbook, so a CoW-layer mock would only drag
 # the domain crates into this crate's dev graph.
 nexum-sdk-test = { path = "../nexum-sdk-test" }
-# Pins the strum-derived fault labels to the single-source vocabulary.
-nexum-world = { path = "../nexum-world" }
 
 # The wasi:http client only links on the wasm guest target; host-side
 # consumers (tests, backtest tooling) compile the `http` module's types

crates/nexum-sdk/src/chain/mod.rs

@@ -9,12 +9,13 @@
 
 pub mod chainlink;
 pub mod eth_call;
-pub mod method;
 pub mod provider;
 pub mod transport;
 
 pub use alloy_chains::Chain;
 pub use eth_call::{eth_call_params, parse_eth_call_result};
-pub use method::ChainMethod;
+/// The read surface is defined once in `nexum-world`; guest and host
+/// re-export the same type, so the allowlist cannot drift.
+pub use nexum_world::ChainMethod;
 pub use provider::{ProviderHost, block_on};
 pub use transport::HostTransport;