Add ACP-224 Fee Manager Precompile

[JonathanOppenheimer]

Why this should be merged

Adds the ACP-224 Fee Manager precompile to enable dynamic gas limit configuration in subnet-evm. This implements the configuration interface specified in ACP-224.

This PR adds the precompile package for reading/writing configuration state, along with tests. The core blockchain integration (using these values for actual gas limit adjustments) is deferred to after SAE, as SAE will redo the ACP-176 mechanism. Module registration is commented out until ready -- this will be done in a follow up "activation" PR.

How this works

The precompile provides three functions with AllowList-based access control:

• setFeeConfig(FeeConfig): Updates configuration (Admin/Manager/Enabled only)
• getFeeConfig(): Retrieves current configuration (public)
• getFeeConfigLastChangedAt(): Returns block number of last update (public)

FeeConfig struct

The FeeConfig struct matches the ACP-224 spec:

Field	Type	Description
validatorTargetGas	bool	Whether target gas is determined by the validator set
targetGas	uint256	Target gas consumption per second (must be 0 when validatorTargetGas is true, >= 1,000,000 otherwise)
staticPricing	bool	Whether gas pricing is static
minGasPrice	uint256	Minimum gas price in wei (must be > 0)
timeToDouble	uint256	Seconds for gas price to double at max capacity (must be 0 when staticPricing is true, > 0 otherwise)

Validation rules

• minGasPrice must always be > 0
• validatorTargetGas = true -> targetGas == 0
• validatorTargetGas = false -> targetGas >= 1,000,000
• staticPricing = true -> timeToDouble == 0
• staticPricing = false -> timeToDouble > 0

see the ACP-224 spec for these.

Need to be documented in RELEASES.md?

Yes, but not in this PR as the module is not yet registered. Once the precompile is fully available and functional, the release notes should be updated.

[Copilot]

Pull request overview

This PR implements the ACP-224 Fee Manager precompile for enabling dynamic gas limit configuration in subnet-evm. It adds the configuration interface specified in ACP-224, providing functions to read and write fee configuration state, with AllowList-based access control. Per the PR description, the precompile package is intentionally incomplete (the core blockchain integration is deferred post-SAE).

Changes:

• Adds ACP224FeeConfig struct, validation (Verify()), and equality check to the commontype package, along with a test helper value
• Adds the full precompile implementation: module registration, contract execution functions (setFeeConfig, getFeeConfig, getFeeConfigLastChangedAt), event packing/unpacking, and chain config integration
• Adds the Solidity interface (IACP224FeeManager.sol), generated ABI, and Go bindings for the new precompile

Reviewed changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
graft/subnet-evm/commontype/fee_config.go	New ACP224FeeConfig struct with Verify(), Equal(), and checkByteLens() methods
graft/subnet-evm/commontype/test_fee_config.go	Adds ValidTestACP224FeeConfig test fixture
graft/subnet-evm/precompile/contracts/acp224feemanager/module.go	Registers the precompile module with its config key and contract address
graft/subnet-evm/precompile/contracts/acp224feemanager/config.go	Precompile Config struct with Equal(), Verify(), and constructor helpers
graft/subnet-evm/precompile/contracts/acp224feemanager/contract.go	Core precompile logic: storage keys, gas costs, state read/write, and function dispatch
graft/subnet-evm/precompile/contracts/acp224feemanager/event.go	FeeConfigUpdated event pack/unpack helpers

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[Copilot]

Pull request overview

Copilot reviewed 7 out of 7 changed files in this pull request and generated 1 comment.

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[Copilot]

Pull request overview

Copilot reviewed 7 out of 7 changed files in this pull request and generated 3 comments.

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Pull request overview

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[ceyonur]

huh would this work as it's? Event data should have 2 different data: data[0]=oldFeeConfig, data[1]=newFeeConfig. Maybe it works due to how UnpackIntoInterface but I'm just surprised as this is not the same way we used in legacy fee manager event.

[JonathanOppenheimer]

yes it works because UnpackIntoInterface with multiple args does field-name matching, unlike the single-arg case which hits copyAtomic. Do you want to change this?