feat(#2): implement tree-based cross-chain permits by re1ro · Pull Request #54 · eco/permit3

re1ro · 2025-10-31T19:18:00Z

Summary

Implement tree-based cross-chain permit system with UI transparency and gas-efficient on-chain verification using TreeNodeLib.

Users sign a complete PermitNode tree structure (full transparency), while the contract receives a compact proof (gas efficient).

Dependencies

⚠️ Depends on PR #53 (feat/tree-lib) - merge that first!

Core Changes

New Structures

PermitNode - UI-readable tree structure for signing
PermitTree - Compact on-chain structure (proofStructure + proof)
Signature - Standardized signature data bundle

New Typehashes

PERMIT3_TYPEHASH - Single-chain permit
MULTICHAIN_PERMIT3_TYPEHASH - Multi-chain tree permit
PERMIT_NODE_TYPEHASH - Internal tree node hashing

Updated Files

src/Permit3.sol - Tree reconstruction using TreeNodeLib
src/PermitBase.sol - Updated for new structures
src/interfaces/IPermit3.sol - New structs and signatures
src/MultiTokenPermit.sol - API adjustments
src/modules/ERC7579ApproverModule.sol - Integration updates

Test Coverage

New Tests:

test/PermitNodeReconstruction.t.sol (540 lines) - Hash reconstruction validation
test/PermitTreeIntegration.t.sol (296 lines) - End-to-end integration
test/NestedStructure.t.sol (137 lines) - EIP-712 nested struct tests

Updated Tests:

test/Permit3.t.sol, test/Permit3Edge.t.sol, test/Permit3Witness.t.sol
test/MultiTokenPermit.t.sol and related tests

Test Results:

✅ All 138 permit tests pass
✅ Build successful

JavaScript Utilities

Complete toolkit for tree construction:

utils/permitNodeHelpers.js (1,192 lines) - Tree construction & proof generation
utils/test-permitNode.js (288 lines) - JS test suite
utils/merkle-helpers.js (636 lines) - Legacy Merkle utilities
Comprehensive README documentation

Gas Performance

2 chains: ~85,000 gas
4 chains: ~90,000 gas
8 chains: ~95,000 gas
Each proof element adds ~3,000-5,000 gas

Key Benefits

✅ UI Transparency: Users see all chains/permits in wallet before signing
✅ Gas Efficient: O(log n) proof size with linear gas scaling
✅ Deterministic: Three clear combination rules prevent ambiguity
✅ Secure: Maximum depth validation, unused bit checks

API Example

Before (single-chain):

permit(owner, salt, deadline, timestamp, permits, signature);

After (single-chain):

Signature memory sig = Signature({owner, salt, deadline, timestamp, signature});
permit(permits, sig);

After (multi-chain):

PermitTree memory tree = PermitTree({
    currentChainPermits: chainPermits,
    proofStructure: proofStructure,
    proof: proof
});
permit(tree, sig);

Documentation

Updated README with:

Tree-Based Cross-Chain Permits section
JavaScript usage examples
Gas cost benchmarks
Security model explanation

🤖 Generated with Claude Code

Implement tree-based cross-chain permit system with UI transparency and gas-efficient on-chain verification using TreeNodeLib. Core changes: - Add PermitNode tree structure for UI-readable permits - Add PermitTree compact on-chain structure - Add Signature struct for cleaner API - New typehashes: PERMIT3_TYPEHASH, MULTICHAIN_PERMIT3_TYPEHASH, PERMIT_NODE_TYPEHASH - Refactor Permit3.sol to use tree reconstruction - Update PermitBase.sol for new structures - Update all permit-related interfaces Test coverage: - PermitNodeReconstruction.t.sol (540 lines) - Hash reconstruction tests - PermitTreeIntegration.t.sol (296 lines) - End-to-end integration - NestedStructure.t.sol (137 lines) - EIP-712 nested struct tests - Updated Permit3.t.sol, Permit3Edge.t.sol, Permit3Witness.t.sol - Updated MultiTokenPermit.t.sol and related tests JavaScript utilities: - permitNodeHelpers.js (1,192 lines) - Complete tree construction toolkit - test-permitNode.js (288 lines) - JS test suite - merkle-helpers.js (636 lines) - Legacy Merkle utilities - Comprehensive README documentation Key benefits: - Users sign complete tree structure (full transparency) - Contract receives compact proof (gas efficient) - O(log n) proof size with linear gas scaling - Three deterministic combination rules 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude <noreply@anthropic.com>

Copilot

Pull Request Overview

This pull request introduces comprehensive JavaScript utilities for Permit3's tree-based cross-chain permit system. The changes add implementation of EIP-712 PermitNode tree construction, proof generation, and Solidity test infrastructure to support the new tree-based permit architecture.

Key Changes:

Implementation of permitNodeHelpers.js with tree encoding/proof generation algorithms matching on-chain Solidity reconstruction
Addition of test-permitNode.js comprehensive test suite with 6 test scenarios
New Solidity test helpers (TreeNodeLibTester, PermitNodeLibTester) for testing generic tree reconstruction
Extensive integration tests for tree-based permit execution across various topologies

Reviewed Changes

Copilot reviewed 29 out of 30 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
utils/permitNodeHelpers.js	Core implementation of PermitNode tree hashing, proof generation, and encoding matching Solidity reconstruction algorithm
utils/test-permitNode.js	Comprehensive test script validating tree construction and proof generation for 2-5 chain scenarios
utils/merkle-helpers.js	Legacy Merkle tree utilities with backward compatibility aliases for permit node structures
utils/README.md	Documentation covering tree concepts, encoding format, usage examples, and migration guide
utils/package.json	Package configuration with ethers v5, merkletreejs, and keccak256 dependencies
test/utils/TreeNodeLibTester.sol	Generic tree node library test wrapper exposing internal combination functions
test/utils/PermitNodeLibTester.sol	Permit-specific wrapper around TreeNodeLib maintaining backward compatibility
test/utils/TestBase.sol	Enhanced base test with `_hashPermitNode()` helper and sorting utilities
test/TreeNodeLib.t.sol	Comprehensive tests (65 tests) for generic TreeNodeLib with both permit and nonce typehashes
test/PermitTreeIntegration.t.sol	End-to-end integration tests for tree-based permit execution with various topologies
test/PermitNodeReconstruction.t.sol	Tests for EIP-712 PermitNode hash reconstruction across 15 different tree structures
test/Permit3Witness.t.sol	Updated witness tests migrated from merkle proofs to tree structures
test/Permit3.t.sol	Updated core permit tests using new tree-based signature structure

Files not reviewed (1)

utils/package-lock.json: Language not supported

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utils/permitNodeHelpers.js

utils/README.md

utils/test-permitNode.js

# Conflicts: # test/ZeroAddressValidation.t.sol

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

fish-sammy · 2025-11-07T07:17:50Z

utils/README.md

Are these supposed to be committed? If so, let's do all the JS things separately.

fish-sammy · 2025-11-10T16:57:01Z

src/interfaces/IPermit3.sol

+     * @dev Used in EIP-712 signatures to provide transparency to users about what they're signing
+     * @dev Can represent either leaf nodes (ChainPermits) or internal tree nodes (nested levels)
+     * @dev Both arrays should be ordered by hash value as merkle tree construction requires
+     * @param levels Child tree nodes for internal nodes (ordered by hash value)


fish-sammy · 2025-11-10T16:57:18Z

src/interfaces/IPermit3.sol

+     * @param proofStructure Compact tree encoding
+     * @param currentChainPermits Permit operations for the current chain


Suggested change

* @param proofStructure Compact tree encoding

* @param currentChainPermits Permit operations for the current chain

* @param currentChainPermits Permit operations for the current chain

* @param proofStructure Compact tree encoding

fish-sammy · 2025-11-10T16:58:12Z

src/Permit3.sol

     * @param permits Array of permit operations to execute
-     * @param signature EIP-712 signature authorizing all permits in the batch
     */
    function permit(


Do we really need this function? Why can't the single-chain permit be treated as a single-node tree?

fish-sammy · 2025-11-10T17:06:44Z

src/Permit3.sol

-        // processProof performs validation internally and provides granular error messages
-        params.merkleRoot = MerkleProof.processProof(proof, params.currentChainHash);
+        // Reconstruct the PermitNode hash from the proof and tree structure
+        bytes32 permitNodeHash =


Suggested change

bytes32 permitNodeHash =

bytes32 treeHash =

fish-sammy · 2025-11-10T17:07:40Z

src/Permit3.sol

+        if (block.timestamp > sig.deadline) {
+            revert SignatureExpired(sig.deadline, uint48(block.timestamp));
        }


I'm see this being repeated a lot. Consider moving it to a modifier or _verifySignature

fish-sammy · 2025-11-10T17:10:13Z

src/Permit3.sol

+    function _validateWitnessTypeString(
+        string calldata witnessTypeString
+    ) internal pure {
+        // Validate minimum length
+        if (bytes(witnessTypeString).length == 0) {
+            revert InvalidWitnessTypeString(witnessTypeString);
+        }
+
+        // Validate proper ending with closing parenthesis
+        uint256 witnessTypeStringLength = bytes(witnessTypeString).length;
+        if (bytes(witnessTypeString)[witnessTypeStringLength - 1] != ")") {
+            revert InvalidWitnessTypeString(witnessTypeString);
+        }
+    }


Honestly, I don't think this function is needed. It doesn't do much for us. There's much more that can go wrong than empty or the last char being not ")".

fish-sammy · 2025-11-10T17:11:23Z

src/Permit3.sol

-     * @param signature EIP-712 signature authorizing all permits with witness
+     * @param witness Witness data containing witness hash and type string
     */
    function permitWitness(


I understand how this works, but what's the usecase. Who would need it?

fish-sammy · 2025-11-10T17:12:00Z

src/Permit3.sol

+        IPermit3.Signature calldata sig,
+        IPermit3.PermitTree calldata tree,
+        IPermit3.Witness calldata witness
+    ) internal view returns (TreeWitnessContext memory ctx) {


Suggested change

) internal view returns (TreeWitnessContext memory ctx) {

) internal pure returns (TreeWitnessContext memory ctx) {

Also, don't see why we need this struct TreeWitnessContext. Only .signedHash is ever used but the other two fields are never used.

@param

Address PR feedback: - Fix @param name from 'levels' to 'nodes' in PermitNode struct - Reorder @param documentation to match struct field order in PermitTree Changes: - Corrected parameter documentation to match actual struct fields - Improved documentation clarity and consistency

…me7mv5nn2QUpN6XQ docs: fix documentation formatting in IPermit3

Copilot AI review requested due to automatic review settings October 31, 2025 19:18

re1ro mentioned this pull request Oct 31, 2025

feat(#3): implement tree-based nonce cancellation #55

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Copilot AI reviewed Oct 31, 2025

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re1ro and others added 6 commits October 31, 2025 15:26

style: run forge fmt

09160d6

Merge branch 'feat/tree-lib' into feat/permit-tree

fa52a89

# Conflicts: # test/ZeroAddressValidation.t.sol

Update utils/README.md

bd0aa42

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Update utils/test-permitNode.js

6e19895

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Update utils/test-permitNode.js

a197cd6

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Update utils/permitNodeHelpers.js

305b2b1

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

re1ro changed the title ~~feat: implement tree-based cross-chain permits~~ feat(#2): implement tree-based cross-chain permits Oct 31, 2025

re1ro changed the base branch from main to feat/tree-lib October 31, 2025 19:37

re1ro added 2 commits October 31, 2025 15:39

fix: update ZeroAddressValidation tests to use new permit API

8b4511d

refactor: simplify witness initialization in ZeroAddressValidation tests

16a49e8

fish-sammy requested changes Nov 10, 2025

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claude and others added 3 commits November 21, 2025 22:27

fix: correct indentation in test comment

21c3316

Merge pull request #57 from eco/claude/pr54-address-feedback-01Mu5xjL…

b8d0c04

…me7mv5nn2QUpN6XQ docs: fix documentation formatting in IPermit3

		* @param proofStructure Compact tree encoding
		* @param currentChainPermits Permit operations for the current chain

	) internal view returns (TreeWitnessContext memory ctx) {
	) internal pure returns (TreeWitnessContext memory ctx) {

Conversation

re1ro commented Oct 31, 2025

Summary

Dependencies

Core Changes

New Structures

New Typehashes

Updated Files

Test Coverage

JavaScript Utilities

Gas Performance

Key Benefits

API Example

Documentation

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