Return zero for unsupported EIP-4788 calls

EVM.md

@@ -61,9 +61,9 @@ Implemented in this workspace:
   creating or funding the corresponding EVM-native purse identity.
 - [EIP-7702][eip-7702] type `0x04` set-code transactions, with authorization
   lists passed through to `revm` for Prague execution.
-- [EIP-4788][eip-4788] beacon roots predeploy, native pre-block state update,
-  and native direct-call lookup. Casper stores the parent Casper block hash as
-  the root value.
+- [EIP-4788][eip-4788] beacon roots predeploy with a native direct-call
+  shortcut that returns a zero root. Casper does not support beacon-root
+  history or pre-block state updates.
 - [EIP-2935][eip-2935] block-hash history predeploy and native direct-call
   lookup backed by indexed Casper block headers.
 
@@ -80,7 +80,8 @@ Implemented in the sidecar workspace for validation:
 - `eth_getTransactionReceipt` projects logs stored in
   `ExecutionResult::Evm` as Ethereum receipt log entries.
 - `eth_getBlockByNumber` projects `parentBeaconBlockRoot` as the parent Casper
-  block hash, matching Casper's [EIP-4788][eip-4788] system-contract value.
+  block hash. This sidecar projection is independent of the zero-valued
+  [EIP-4788][eip-4788] contract shortcut.
 - Development-only Cargo patches pointing sidecar at this node workspace for
   unreleased `casper-types` and `casper-binary-port` changes.
 
@@ -107,7 +108,7 @@ Ethereum JSON-RPC method names below refer to the Ethereum
 | `EvmSpec::Prague` / `revm::SpecId::PRAGUE` | Implemented. | Execution behavior is delegated to `revm`; Casper does not maintain its own EVM interpreter. |
 | [EIP-2537][eip-2537] BLS12-381 precompiles | Delegated to `revm`. | Expected at `0x0b` through `0x11`, but Casper-owned conformance tests are still needed for gas costs, malformed input, subgroup checks, and failure behavior. |
 | [EIP-2935][eip-2935] block-hash history contract | Implemented with Casper storage semantics. | The standard address, bytecode, and 8191-block interface are present, but direct calls read indexed LMDB block headers instead of Merkleized contract storage. There is no pre-block system call or gradual ring-buffer fill. |
-| [EIP-4788][eip-4788] beacon roots contract | Implemented. | The standard address, bytecode, and interface are present. Casper writes and reads the parent Casper block hash natively through block-global state rather than executing the predeploy bytecode. |
+| [EIP-4788][eip-4788] beacon roots contract | Intentionally unsupported (non-goal). | The standard address and bytecode are present, but direct `CALL` and `STATICCALL` lookups are intercepted and always return an all-zero root. Casper does not write beacon-root history. Do not treat this product decision as an open compatibility gap. |
 | [EIP-6110][eip-6110] validator deposit requests | Missing / decision needed. | Ethereum-specific deposit-log-to-request flow. Full support requires [EIP-7685][eip-7685] request construction and commitment. |
 | [EIP-7002][eip-7002] withdrawal request predeploy | Missing / decision needed. | Contract-visible predeploy at `0x00000961Ef480Eb55e80D19ad83579A64c007002` is absent. Full support requires queue/fee state, post-block extraction, and [EIP-7685][eip-7685] request output. |
 | [EIP-7251][eip-7251] consolidation request predeploy | Missing / decision needed. | Contract-visible predeploy at `0x0000BBdDc7CE488642fb579F8B00f3a590007251` is absent. Full support has the same request-output dependency as EIP-7002. |
@@ -136,7 +137,7 @@ Ethereum JSON-RPC method names below refer to the Ethereum
 | `NUMBER`, `TIMESTAMP`, `GASLIMIT`, `BASEFEE` | Implemented. | Timestamp is Casper block time in seconds. Base fee is chainspec-configured and wei-denominated through `wei_per_mote`, not Ethereum's dynamic base-fee adjustment. |
 | `COINBASE` | Implemented with Casper semantics. | The address is derived from the Casper block proposer public key. |
 | `CHAINID` | Implemented. | Transaction chain ID is enforced against chainspec `[evm].chain_id`. |
-| `PREVRANDAO` | Weak / missing semantic mapping. | Casper does not plumb a randomness field into the EVM block context, so contracts should not treat it as Ethereum beacon randomness. |
+| `PREVRANDAO` | Implemented with Casper semantics. | The value is derived from the parent Casper block's accumulated seed. It provides Casper randomness, not Ethereum beacon-chain RANDAO semantics. |
 | `BLOBHASH` and blob-related block context | Missing / misleading. | No accepted blob transactions means no meaningful blob versioned hashes, blob gas, or blob fee context. |
 | Fee charging | Casper-specific. | `revm` fee charging is disabled; Casper hold, refund, and fee accounting owns balance effects according to the chainspec. |
 
@@ -181,26 +182,28 @@ executor.
 previous Cancun/Dencun upgrade. It is included in this review because a Prague
 Ethereum-compatible environment has this contract. In this branch, Casper
 installs the exact EIP-4788 runtime bytecode at
-`0x000F3df6D732807Ef1319fB7B8bB8522d0Beac02`, writes the parent hash natively
-before user transactions, and serves direct calls through the Casper
-precompile provider. It uses:
+`0x000F3df6D732807Ef1319fB7B8bB8522d0Beac02`. Direct `CALL` and `STATICCALL`
+lookups are intercepted by the Casper precompile provider and currently
+return:
 
 ```text
-parentBeaconBlockRoot := parent Casper block hash
+parentBeaconBlockRoot := 0x0000000000000000000000000000000000000000000000000000000000000000
 ```
 
-This gives contracts a deterministic consensus-root oracle for Casper. It is
-not strict Ethereum beacon-chain semantics. The detailed, audited compatibility
-matrix is in [Current Status](#current-status).
+Casper does not support Ethereum beacon-chain roots, run the EIP-4788 pre-block
+system call, or persist its ring buffer. The zero-valued response is not strict
+EIP-4788 semantics. This is an intentional product non-goal, not an open gap;
+revisit it only if the product decision changes. The detailed, audited
+compatibility matrix is in [Current Status](#current-status).
 
 Casper installs the exact EIP-2935 runtime bytecode at
 `0x0000F90827F1C53a10cb7A02335B175320002935`. Direct `CALL` and `STATICCALL`
 lookups are intercepted natively and read indexed Casper block headers through
 the data access layer. Casper does not execute an EIP-2935 block-boundary
 system call or populate the standard contract-storage ring.
 
-The highest-priority smart-contract-visible gaps after EIP-4788 and EIP-2935
-are request predeploy decisions for [EIP-7002][eip-7002] and
+The highest-priority smart-contract-visible gaps are request predeploy
+decisions for [EIP-7002][eip-7002] and
 [EIP-7251][eip-7251], and explicit Prague conformance coverage for
 [EIP-2537][eip-2537], [EIP-7623][eip-7623], and [EIP-7702][eip-7702].
 

execution_engine_testing/tests/src/test/explorer/faucet.rs

@@ -663,14 +663,14 @@ fn faucet_costs() {
     // This test will fail if execution costs vary.  The expected costs should not be updated
     // without understanding why the cost has changed.  If the costs do change, it should be
     // reflected in the "Costs by Entry Point" section of the faucet crate's README.md.
-    const EXPECTED_FAUCET_INSTALL_COST: u64 = 119_810_320_929;
+    const EXPECTED_FAUCET_INSTALL_COST: u64 = 118_807_845_390;
     const EXPECTED_FAUCET_INSTALL_COST_ALT: u64 = 149_230_872_143;
 
-    const EXPECTED_FAUCET_SET_VARIABLES_COST: u64 = 79_749_265;
+    const EXPECTED_FAUCET_SET_VARIABLES_COST: u64 = 79_790_440;
 
-    const EXPECTED_FAUCET_CALL_BY_INSTALLER_COST: u64 = 2_652_913_398;
+    const EXPECTED_FAUCET_CALL_BY_INSTALLER_COST: u64 = 2_652_954_573;
 
-    const EXPECTED_FAUCET_CALL_BY_USER_COST: u64 = 2_558_746_881;
+    const EXPECTED_FAUCET_CALL_BY_USER_COST: u64 = 2_558_820_996;
 
     let installer_account = AccountHash::new([1u8; 32]);
     let user_account: AccountHash = AccountHash::new([2u8; 32]);

executor/evm/src/db.rs

@@ -4,7 +4,6 @@ use casper_storage::{
     data_access_layer::DataAccessLayer,
     eip2935,
     global_state::{error::Error as GlobalStateError, state::StateReader},
-    tracking_copy::TrackingCopyExt,
     TrackingCopy,
 };
 use casper_types::{evm, CLValue, EvmAddr, Key, StoredValue, U512};
@@ -92,38 +91,6 @@ where
         };
         self.block_hash_at_height(requested_height).map(Some)
     }
-
-    /// Executes the native EIP-4788 `get` operation.
-    ///
-    /// The lookup is backed only by the current tracking copy; EVM execution must not depend on
-    /// locally retained block history.
-    pub(crate) fn eip4788_get(&mut self, input: &[u8]) -> Result<Option<B256>, DbError> {
-        // EIP-4788 accepts one uint256 timestamp.  Values wider than u64 must revert rather
-        // than truncate to a colliding ring-buffer timestamp.
-        if input.len() != 32 || input[..24].iter().any(|byte| *byte != 0) {
-            return Ok(None);
-        }
-
-        let timestamp = u64::from_be_bytes(
-            input[24..]
-                .try_into()
-                .expect("the final 8 bytes of a 32-byte input have fixed length"),
-        );
-        if timestamp == 0 {
-            return Ok(None);
-        }
-
-        let Some((stored_timestamp, block_hash)) =
-            self.tracking_copy.get_eip4788_parent_hash(timestamp)?
-        else {
-            return Ok(None);
-        };
-        if stored_timestamp != timestamp {
-            return Ok(None);
-        }
-
-        Ok(Some(tx::to_revm_block_hash(block_hash)))
-    }
 }
 
 impl<R, S> Database for CasperDb<'_, R, S>

executor/evm/src/precompiles.rs

@@ -82,12 +82,14 @@ where
             && inputs.bytecode_address == beacon_roots_address
             && matches!(inputs.scheme, CallScheme::Call | CallScheme::StaticCall)
         {
-            // Copy the input before borrowing the database mutably.  The input may be backed by
-            // revm's shared memory buffer.
-            let input = inputs.input.bytes(context);
-            let lookup_result = context.db_mut().eip4788_get(&input);
-            let result =
-                native_get_result(context, lookup_result, inputs.gas_limit, inputs.reservoir);
+            // Casper does not support Ethereum beacon-chain roots. Keep the predeploy callable
+            // without maintaining placeholder state.
+            let result = native_get_result(
+                context,
+                Ok(Some(B256::ZERO)),
+                inputs.gas_limit,
+                inputs.reservoir,
+            );
             return Ok(Some(result));
         }
 

executor/evm/src/request.rs

@@ -88,6 +88,7 @@ pub struct BlockContext {
     ///
     /// Defaults to chainspec `[evm].base_fee * [evm].wei_per_mote`.
     pub base_fee: Option<u128>,
+    /// Casper parent-block accumulated seed exposed through the `PREVRANDAO` opcode.
     pub prevrandao: evm::Hash,
 }