Mtmu integration

[julianlen]

Description

Motivation and Context

How Has This Been Tested?

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• Tests for the changes have been added (for bug fixes / features)
• Requires Activation Code (Hard Fork)

• Other information:

[github-actions]

Dependency Review

✅ No vulnerabilities or license issues or OpenSSF Scorecard issues found.

Scanned Files

None

[github-actions]

RSKj Core Automated Tests

rskj node built from mtmu-integration.

Suite	Result	Branch tested	Run
JSON-RPC	✅ success	main	run
Hardhat	✅ success	main	run
K6	✅ success	main	run

[Copilot]

Pull request overview

Integrates “MTMU” behavior for federation funds migration by introducing RSKIP455 and updating the bridge migration flow to support migration transactions with multiple outputs (and updated max inputs), including new constants, activation wiring, and extensive test coverage updates across peg/migration scenarios.

Changes:

• Added RSKIP455 to consensus rules and activation configuration templates (reference.conf/expected.conf) and updated activation test fixtures.
• Updated bridge constants to include migration-specific limits/thresholds (max inputs/outputs and per-output migration value) and added output-splitting logic in BridgeUtils.
• Refactored migration processing in BridgeSupport to build multi-output migration transactions post-RSKIP455, and updated/expanded tests to validate new behavior.

Reviewed changes

Copilot reviewed 18 out of 19 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
rskj-core/src/main/java/co/rsk/peg/BridgeSupport.java	Refactors migration processing flow; switches to legacy vs post-RSKIP455 builder paths and updates clearing behavior.
rskj-core/src/main/java/co/rsk/peg/BridgeUtils.java	Adds calculation of migration output values (single vs fixed-value vs evenly distributed outputs).
rskj-core/src/main/java/co/rsk/peg/ReleaseTransactionBuilder.java	Changes migration tx builder to accept a list of output values (multi-output support).
rskj-core/src/main/java/co/rsk/peg/constants/BridgeConstants.java	Introduces migration-related constants (max inputs/outputs, per-output value) and activation-based max-input selection.
rskj-core/src/main/java/co/rsk/peg/constants/BridgeMainNetConstants.java	Sets new migration constants for mainnet.
rskj-core/src/main/java/co/rsk/peg/constants/BridgeTestNetConstants.java	Sets new migration constants for testnet.
rskj-core/src/main/java/co/rsk/peg/constants/BridgeRegTestConstants.java	Sets new migration constants for regtest.
rskj-core/src/main/java/org/ethereum/config/blockchain/upgrades/ConsensusRule.java	Adds RSKIP455 consensus rule identifier.
rskj-core/src/main/resources/reference.conf	Wires rskip455 to the tbd1000 upgrade in the reference configuration.
rskj-core/src/main/resources/expected.conf	Adds rskip455 placeholder entry for config generation expectations.
rskj-core/src/test/java/org/ethereum/config/blockchain/upgrades/ActivationConfigTest.java	Updates activation config parsing expectations to include rskip455.
rskj-core/src/test/java/org/ethereum/config/blockchain/upgrades/ActivationConfigsForTest.java	Adds RSKIP455 to the tbd1000 activation set used by tests.
rskj-core/src/test/java/co/rsk/peg/ReleaseTransactionAssertions.java	Adds assertions for multi-output migration transactions and tx-size checks.
rskj-core/src/test/java/co/rsk/peg/ReleaseTransactionBuilderTest.java	Updates migration tx tests to pass lists and adds multi-output migration coverage.
rskj-core/src/test/java/co/rsk/peg/BridgeUtilsTest.java	Adds dedicated tests for calculateMigrationTransactionOutputsValues across thresholds and boundaries.
rskj-core/src/test/java/co/rsk/peg/BridgeSupportTestUtil.java	Adds helper for inserting multiple flyover UTXOs into storage.
rskj-core/src/test/java/co/rsk/peg/BridgeSupportProcessFundsMigrationTest.java	Large expansion/refactor of migration tests to validate RSKIP455 behavior across many UTXO/value cases.
rskj-core/src/test/java/co/rsk/peg/federation/FederationChangeIT.java	Updates integration test to account for post-RSKIP455 “migrate then clear” two-call behavior.
rskj-core/src/test/java/co/rsk/peg/constants/BridgeConstantsTest.java	Adds tests for new migration constants and removes redundant @ParameterizedTest() parentheses.

[sonarqubecloud]

Quality Gate passed

Issues
1 New issue
0 Accepted issues

Measures
0 Security Hotspots
96.7% Coverage on New Code
0.8% Duplication on New Code

See analysis details on SonarQube Cloud

[Copilot]

Pull request overview

Copilot reviewed 20 out of 21 changed files in this pull request and generated no new comments.

Comments suppressed due to low confidence (1)

rskj-core/src/main/java/co/rsk/peg/BridgeSupport.java:1293

• In processFundsMigrationPastMigrationAge, a failed or thrown migration build leaves migrationTransactionCreated false, which causes the retiring federation to be cleared post-RSKIP455 even when the failure could be transient (e.g., INSUFFICIENT_MONEY / EXCEED_MAX_TRANSACTION_SIZE / COULD_NOT_ADJUST_DOWNWARDS), and also clears on exceptions without logging the stacktrace. This risks stopping further migration attempts while funds may still be present. Consider: (1) log the exception, (2) don’t clear on exceptions, and (3) post-RSKIP455 only clear when the builder response is definitively non-recoverable (e.g., DUSTY_SEND_REQUESTED).

        try {
            ReleaseTransactionBuilder.BuildResult migrationTransactionResult = buildMigrationTransaction(rskTxHash, retiringFederationWallet);
            migrationTransactionCreated = isMigrationTransactionCreated(migrationTransactionResult);
            if (migrationTransactionCreated) {
                settleMigrationTransaction(migrationTransactionResult, rskTxHash, availableUTXOs);