feat(l1): add `BlockAccessListTracer` and `debug_getBlockAccessList`. #5784

lakshya-sky · 2026-01-08T17:45:13Z

Motivation

Description

Checklist

Updated STORE_SCHEMA_VERSION (crates/storage/lib.rs) if the PR includes breaking changes to the Store requiring a re-sync.

Closes #issue_number

…ambdaclass#5706) **Motivation** * `./hive --sim ethereum/eels/execute-blobs --client ethrex` fails with `execution_testing.rpc.rpc_types.JSONRPCError: JSONRPCError(code=-32603, message=Internal Error: Parent block not found)`. * GetBlobBaseFee is using parents header which causes to get blob base fee for genesis blocks. According to the specs `excess_blob_gas` is **Running total of blob gas consumed in excess of the target, prior to this block.**. That means we need to use latest block header only. **Description** - use latest block header and remove accessing parent header. Co-authored-by: lakshya-sky <lakshya-sky@users.noreply.github.com> Co-authored-by: Edgar <git@edgl.dev>

…rly`.

…tbal-rpc

…bal-rpc

Copilot

Pull request overview

This pull request adds support for block access list tracing and the Amsterdam fork. The key changes include:

Introduction of a flexible Tracer trait with multiple implementations (BlockAccessListTracer, LevmCallTracer, NoOpTracer)
New debug_getBlockAccessList RPC endpoint for retrieving block access lists
Addition of the Amsterdam fork with block_access_list_hash in block headers
New engine_newPayloadV5 RPC method supporting block access lists
Refactoring of VM tracer integration from concrete LevmCallTracer to trait object Rc<RefCell<dyn Tracer>>

Reviewed changes

Copilot reviewed 35 out of 35 changed files in this pull request and generated 11 comments.

Show a summary per file

File	Description
crates/vm/levm/src/tracing/mod.rs	Defines the new `Tracer` trait with hooks for state changes and account accesses
crates/vm/levm/src/tracing/block_access_list_tracer.rs	Implements tracer that tracks all state changes for generating block access lists
crates/vm/levm/src/tracing/call_tracer.rs	Refactors `LevmCallTracer` to implement the `Tracer` trait
crates/vm/levm/src/vm.rs	Updates VM to use trait object for tracer, adds new `call()` method
crates/vm/levm/src/opcode_handlers/*.rs	Adds tracer notifications throughout opcode handlers
crates/vm/levm/src/db/gen_db.rs	Integrates tracer hooks into database operations
crates/common/types/block_access_list.rs	Defines data structures for block access lists with RLP encoding/decoding
crates/networking/rpc/debug/block_access_list.rs	Implements RPC handler for `debug_getBlockAccessList`
crates/networking/rpc/engine/payload.rs	Adds `engine_newPayloadV5` handler with block access list validation
crates/common/types/genesis.rs	Adds Amsterdam fork configuration and ordering of fork-checking methods
crates/vm/backends/mod.rs	Adds `generate_bal` flag to control block access list generation
crates/blockchain/tracing.rs	Implements `trace_block_access_list` method for blockchain

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Copilot · 2026-01-08T17:51:26Z

crates/vm/levm/src/tracing/block_access_list_tracer.rs

+        if self.idx == 0 {
+            self.idx = self.idx.saturating_add(1);
+        }
+    }


The tracer index initialization in txn_start is inconsistent. When idx is 0, it increments to 1, but then txn_end always increments. This means the first transaction will have idx=1, but if there are no transactions in a block, idx stays at 0. Consider starting at idx=1 in the constructor or documenting why idx=0 should be skipped.

Copilot · 2026-01-08T17:51:26Z

crates/vm/levm/src/db/gen_db.rs

        let acc = self.get_account_mut(address)?;
+        let old_hash = acc.info.code_hash;
        let code_hash = new_bytecode.hash;
        acc.info.code_hash = new_bytecode.hash;
-        self.db.codes.entry(code_hash).or_insert(new_bytecode);
+        self.db
+            .codes
+            .entry(code_hash)
+            .or_insert(new_bytecode.clone());
+        let old = self.db.get_code(old_hash).cloned()?;
+        self.tracer
+            .borrow_mut()
+            .on_code_change(address, old, new_bytecode, self.db);


Potential issue: on_code_change is called in update_account_bytecode, but there's no corresponding on_account_access call for the address before accessing/modifying the account. This is inconsistent with other methods like increase_account_balance and decrease_account_balance which call on_account_access first.

Copilot · 2026-01-08T17:51:27Z

crates/common/types/block_access_list.rs

+
+#[derive(Default, Debug, Serialize, Deserialize, Clone, PartialEq)]
+pub struct CodeChange {
+    #[serde(rename = "TxIdx")]


Inconsistent serialization naming: CodeChange uses TxIdx (line 139) while other similar structs like NonceChange (line 106), BalanceChange (line 73), and StorageChange (line 14) use txIndex. This should be standardized to txIndex for consistency.

Suggested change

#[serde(rename = "TxIdx")]

#[serde(rename = "txIndex")]

Copilot · 2026-01-08T17:51:27Z

crates/blockchain/tracing.rs

+        // // Obtain the block's parent state
+        // let mut vm = self
+        //     .rebuild_parent_state(block.header.parent_hash, reexec)
+        //     .await?;
+        // // Run anything necessary before executing the block's transactions (system calls, etc)
+        // vm.rerun_block(&block, Some(0))?;
+


Dead code: There are commented-out lines that reference rebuild_parent_state and rerun_block. If this code is intended for future use, it should be documented with a TODO comment explaining why it's commented out. Otherwise, it should be removed to improve code clarity.

Suggested change

// // Obtain the block's parent state

// let mut vm = self

// .rebuild_parent_state(block.header.parent_hash, reexec)

// .await?;

// // Run anything necessary before executing the block's transactions (system calls, etc)

// vm.rerun_block(&block, Some(0))?;

Copilot · 2026-01-08T17:51:27Z

tooling/ef_tests/state/runner/revm_runner.rs

        Fork::BPO3 => SpecId::OSAKA,
        Fork::BPO4 => SpecId::OSAKA,
        Fork::BPO5 => SpecId::OSAKA,
+        Fork::Amsterdam => todo!(),


Missing implementation: The Fork::Amsterdam mapping to SpecId is left as todo!(). This will cause a panic at runtime if Amsterdam fork tests are executed. The appropriate SpecId should be mapped or at a minimum this should return a proper error rather than panicking.

Copilot · 2026-01-08T17:51:28Z

crates/networking/rpc/engine/payload.rs

+        let chain_config = context.storage.get_chain_config();
+
+        if !chain_config.is_amsterdam_activated(block.header.timestamp) {
+            return Err(RpcErr::UnsuportedFork(format!(


Typo in error message: "UnsuportedFork" should be "UnsupportedFork" (missing 'p').

Suggested change

return Err(RpcErr::UnsuportedFork(format!(

return Err(RpcErr::UnsupportedFork(format!(

Copilot · 2026-01-08T17:51:28Z

crates/networking/rpc/engine/payload.rs

+    // This method follows the same specification as `engine_newPayloadV4` additionally
+    // rejects payload without block access list


The comment in validate_execution_payload_v4 mentions "This method follows the same specification as engine_newPayloadV4" but the function is actually validating payload requirements for V5 (Amsterdam fork with block_access_list). The comment should clarify that this validates V4/V5 payloads, or the function should be renamed to better reflect its purpose.

Suggested change

// This method follows the same specification as `engine_newPayloadV4` additionally

// rejects payload without block access list

// This method builds on the `engine_newPayloadV3` specification and additionally

// enforces the Amsterdam (V5) requirement that `block_access_list` is present,

// i.e. it validates payloads suitable for Engine API V4/V5.

Copilot · 2026-01-08T17:51:28Z

crates/vm/levm/src/db/gen_db.rs

    pub fn increment_account_nonce(&mut self, address: Address) -> Result<u64, InternalError> {
        let account = self.get_account_mut(address)?;
+        let old = account.info.nonce;
        account.info.nonce = account
            .info
            .nonce
            .checked_add(1)
            .ok_or(InternalError::Overflow)?;
-        Ok(account.info.nonce)
+        let new = account.info.nonce;
+        if old != new {
+            self.tracer
+                .borrow_mut()
+                .on_nonce_change(address, old, new, self.db);
+        }
+        Ok(new)
    }


Missing tracer notification: increment_account_nonce doesn't call on_account_access before accessing the account, which is inconsistent with other account modification methods like increase_account_balance and decrease_account_balance.

Copilot · 2026-01-08T17:51:29Z

crates/vm/levm/src/tracing/block_access_list_tracer.rs

+    fn txn_end(
+        &mut self,
+        _gas_used: u64,
+        err: Option<String>,


The err parameter in txn_end is not prefixed with underscore but is unused. This should either be renamed to _err for consistency with other unused parameters, or the error should be handled (e.g., to roll back changes on transaction failure).

Suggested change

err: Option<String>,

_err: Option<String>,

Copilot · 2026-01-08T17:51:29Z

crates/vm/backends/mod.rs

+        // if self.generate_bal {
+        //     tracer = Rc::new(RefCell::new());
+        // }


Dead code: Commented-out code that suggests generating a BlockAccessList tracer based on self.generate_bal. This should either be implemented properly or removed. The current implementation always uses NoOpTracer which means generate_bal has no effect in this method.

Suggested change

// if self.generate_bal {

// tracer = Rc::new(RefCell::new());

// }

…tbal-rpc

lakshya-sky and others added 30 commits December 22, 2025 21:04

feat(l1): add amsterdam fork to chain config

6540036

update revm runner with todo and fix the check error

733f4bd

fix tests

c838262

TODO: need to add bal in block header and body

282a56d

added bal types

d7bbe93

derive debug

fe588a0

Merge branch 'feature/bal-types' into feat/add-new-payload-v5

c0aa92f

added rlp conversions

fcf0063

Merge branch 'feature/bal-types' into feat/add-new-payload-v5

c007745

rlp decode

4ce3e76

Merge branch 'feature/bal-types' into feat/add-new-payload-v5

5412b37

payload v5 method working

5dcb02c

feature(l1): introduce a trait for vm tracers

5d502e2

rename to tracing and remove disabled from call tracer

c97f7d6

use depth tracing exits, unify and remove exit_context and `exit_ea…

51c5a09

…rly`.

rearranged tracer method order and add tx related methods

16e9495

pass env to txn_start

1b183ea

update the trait to have db on methods.

b7ddf0d

pass err in txn-end method

e086501

Merge branch 'main' into feature/design-tracer-trait

a1c705e

Merge branch 'feat/eip-7928' into feature/bal-tracer-getbal-rpc

c6dd029

update opcode handles to call tracer hooks

a051471

Merge branch 'feature/design-tracer-trait' into feature/bal-tracer-ge…

02d8bac

…tbal-rpc

able to get result from debug_getBlockAccessList

e471e95

updated order and indent

5db20fe

Merge branch 'main' into feature/add-amsterdam-fork

f9eda40

few test passing for debug_getBlockAccessLists

37b3063

trace block withdrawals with gen db

756a49e

Merge branch 'feature/add-amsterdam-fork' into feature/bal-tracer-get…

7263858

…bal-rpc

Copilot AI review requested due to automatic review settings January 8, 2026 17:45

lakshya-sky requested review from a team, ManuelBilbao, avilagaston9 and ilitteri as code owners January 8, 2026 17:45

lakshya-sky marked this pull request as draft January 8, 2026 17:45

Copilot started reviewing on behalf of lakshya-sky January 8, 2026 17:45 View session

lakshya-sky changed the title ~~feature(l1): add BlockAccessListTracer and debug_getBlockAccessList.~~ feat(l1): add BlockAccessListTracer and debug_getBlockAccessList. Jan 8, 2026

Copilot AI reviewed Jan 8, 2026

View reviewed changes

lakshya-sky added 3 commits January 8, 2026 13:00

remove levm disabled call sites

95e05bc

Merge branch 'main' into feature/design-tracer-trait

9fad79d

Merge branch 'feature/design-tracer-trait' into feature/bal-tracer-ge…

8cc4be7

…tbal-rpc

lakshya-sky mentioned this pull request Jan 8, 2026

Add support for EIP-7928 Block-Level Access Lists(BAL) #5737

Open

4 tasks

lakshya-sky added 5 commits January 8, 2026 13:31

fix ef tests

ee0cd17

fix formating

30bddf5

Merge branch 'feature/design-tracer-trait' into feature/bal-tracer-ge…

2d425f1

…tbal-rpc

Merge branch 'main' into feature/design-tracer-trait

23be737

Merge branch 'feature/design-tracer-trait' into feature/bal-tracer-ge…

5d4ecf4

…tbal-rpc

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feat(l1): add `BlockAccessListTracer` and `debug_getBlockAccessList`. #5784

feat(l1): add `BlockAccessListTracer` and `debug_getBlockAccessList`. #5784

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	return Err(RpcErr::UnsuportedFork(format!(
	return Err(RpcErr::UnsupportedFork(format!(

		// This method follows the same specification as `engine_newPayloadV4` additionally
		// rejects payload without block access list

-    // This method follows the same specification as `engine_newPayloadV4` additionally
-    // rejects payload without block access list
+    // This method builds on the `engine_newPayloadV3` specification and additionally
+    // enforces the Amsterdam (V5) requirement that `block_access_list` is present,
+    // i.e. it validates payloads suitable for Engine API V4/V5.

	// if self.generate_bal {
	// tracer = Rc::new(RefCell::new());
	// }

feat(l1): add BlockAccessListTracer and debug_getBlockAccessList. #5784

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feat(l1): add BlockAccessListTracer and debug_getBlockAccessList. #5784

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feat(l1): add `BlockAccessListTracer` and `debug_getBlockAccessList`. #5784

feat(l1): add `BlockAccessListTracer` and `debug_getBlockAccessList`. #5784