params: EIP-7892 - Blob Parameter Only Hardforks

[fjl]

This is a resubmit of #31820 against the master branch.

[Copilot]

Pull Request Overview

Adds support for five new "BPO" hardfork timestamps (BPO1–BPO5) and integrates them into chain configuration and blob gas scheduling.

• Introduce BPO1Time–BPO5Time in ChainConfig, update display banner, fork-order validation, and compatibility checks.
• Extend BlobScheduleConfig with BPO entries and refactor blob fee and blob scheduling functions to use a new latestBlobConfig helper.
• Replace legacy switch on LatestFork in eip4844.go with unified logic that accounts for BPO forks.

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
params/config.go	Add BPO1–BPO5 time fields, IsBPO methods, integrate into Description, fork ordering, and compatibility checks
consensus/misc/eip4844/eip4844.go	Refactor blob fee and capacity functions to use latestBlobConfig with BPO support; remove direct fork switch

Comments suppressed due to low confidence (4)

params/config.go:782

• [nitpick] The name field uses "bpo1" which is inconsistent with other entries like "pragueTime"; consider using "bpo1Time" to match the JSON key and improve clarity.

		{name: "bpo1", timestamp: c.BPO1Time, optional: true},

params/config.go:414

• New fork fields like BPO1Time through BPO5Time introduce behavior that should be covered by unit tests (e.g., IsBPO methods and fork ordering) to prevent regressions.

	BPO1Time     *uint64 `json:"bpo1Time,omitempty"`     // BPO1 switch time (nil = no fork, 0 = already on bpo1)

params/config.go:684

• Using c.IsLondon for BPO forks may prematurely activate forks before the intended predecessor (e.g., Cancun) is reached; consider using c.IsCancun or the appropriate previous fork condition.

	return c.IsLondon(num) && isTimestampForked(c.BPO1Time, time)

consensus/misc/eip4844/eip4844.go:123

• Using cfg.LondonBlock as the block number when determining blob config may ignore the actual block height for later forks; consider passing the real block number instead of a fixed London threshold.

		london = cfg.LondonBlock

[Copilot]

[nitpick] The IsBPO1 through IsBPO5 methods are nearly identical; consider refactoring into a helper or loop to reduce code duplication and ease future additions.

Suggested change

	// IsBPO1 returns whether time is either equal to the BPO1 fork time or greater.
	func (c *ChainConfig) IsBPO1(num *big.Int, time uint64) bool {
	return c.IsLondon(num) && isTimestampForked(c.BPO1Time, time)
	}
	// IsBPO2 returns whether time is either equal to the BPO2 fork time or greater.
	func (c *ChainConfig) IsBPO2(num *big.Int, time uint64) bool {
	return c.IsLondon(num) && isTimestampForked(c.BPO2Time, time)
	}
	// IsBPO3 returns whether time is either equal to the BPO3 fork time or greater.
	func (c *ChainConfig) IsBPO3(num *big.Int, time uint64) bool {
	return c.IsLondon(num) && isTimestampForked(c.BPO3Time, time)
	// IsForked returns whether time is either equal to the specified fork time or greater.
	func (c *ChainConfig) IsForked(num *big.Int, time uint64, forkTime uint64) bool {
	return c.IsLondon(num) && isTimestampForked(forkTime, time)
	}
	// IsBPO1 returns whether time is either equal to the BPO1 fork time or greater.
	func (c *ChainConfig) IsBPO1(num *big.Int, time uint64) bool {
	return c.IsForked(num, time, c.BPO1Time)
	}
	// IsBPO2 returns whether time is either equal to the BPO2 fork time or greater.
	func (c *ChainConfig) IsBPO2(num *big.Int, time uint64) bool {
	return c.IsForked(num, time, c.BPO2Time)
	}
	// IsBPO3 returns whether time is either equal to the BPO3 fork time or greater.
	func (c *ChainConfig) IsBPO3(num *big.Int, time uint64) bool {
	return c.IsForked(num, time, c.BPO3Time)

[MariusVanDerWijden]

LGTM