feat: add nv24-skeleton (#2029)

* add n24 skeleton

* rustfmt

fvm/Cargo.toml

@@ -61,3 +61,4 @@ gas_calibration = []
 # The current implementation keeps it by default for backward compatibility reason.
 # See <https://github.com/filecoin-project/ref-fvm/issues/2001>
 verify-signature = []
+nv24-dev = []

fvm/src/gas/price_list.rs

@@ -1002,6 +1002,8 @@ impl PriceList {
 pub fn price_list_by_network_version(network_version: NetworkVersion) -> &'static PriceList {
     match network_version {
         NetworkVersion::V21 | NetworkVersion::V22 | NetworkVersion::V23 => &WATERMELON_PRICES,
+        #[cfg(feature = "nv24-dev")]
+        NetworkVersion::V24 => &WATERMELON_PRICES,
         _ => panic!("network version {nv} not supported", nv = network_version),
     }
 }

fvm/src/machine/default.rs

@@ -51,9 +51,14 @@ where
     /// * `blockstore`: The underlying [blockstore][`Blockstore`] for reading/writing state.
     /// * `externs`: Client-provided ["external"][`Externs`] methods for accessing chain state.
     pub fn new(context: &MachineContext, blockstore: B, externs: E) -> anyhow::Result<Self> {
+        #[cfg(not(feature = "nv24-dev"))]
         const SUPPORTED_VERSIONS: RangeInclusive<NetworkVersion> =
             NetworkVersion::V21..=NetworkVersion::V23;
 
+        #[cfg(feature = "nv24-dev")]
+        const SUPPORTED_VERSIONS: RangeInclusive<NetworkVersion> =
+            NetworkVersion::V21..=NetworkVersion::V24;
+
         debug!(
             "initializing a new machine, epoch={}, base_fee={}, nv={:?}, root={}",
             context.epoch, &context.base_fee, context.network_version, context.initial_state_root

shared/src/version/mod.rs

@@ -61,6 +61,8 @@ impl NetworkVersion {
     pub const V22: Self = Self(22);
     /// Waffle (builtin-actors v14)
     pub const V23: Self = Self(23);
+    /// TBD (builtin-actors v15)
+    pub const V24: Self = Self(24);
 
     pub const MAX: Self = Self(u32::MAX);