ForkChoice¶

	Source (upstream pre-purge)	Current
File	`core/forkchoice.go`	`forkchoice_pow.go`
Symbol	`ForkChoice`	`ForkChoice`
Ref	`f4d53133f~1`	`etc/v1.17.3-full-node`

Adds reorgFilter callback field — extension point for MESS artificial finality (set via SetReorgFilter in blockchain_mess.go)

3-way merge — purge → getc ← upstream¶

pre-purgefork-only

↗// ForkChoice is the fork chooser based on the highest total difficulty of the

// chain(the fork choice used in the eth1) and the external fork choice (the fork

// choice used in the eth2). This main goal of this ForkChoice is not only for

// offering fork choice during the eth1/2 merge phase, but also keep the compatibility

// for all other proof-of-work networks.

type ForkChoice struct {

chain ChainReader

rand *mrand.Rand

↗ // preserve is a helper function used in td fork choice.

// Miners will prefer to choose the local mined block if the

// local td is equal to the extern one. It can be nil for light

// client

preserve func(header *types.Header) bool

// reorgFilter is an optional callback that validates whether a reorg

// warranted by TD should actually be applied. Returns nil if allowed,

// non-nil error if the reorg must be rejected.

reorgFilter func(current, extern *types.Header) error

// sideBlockFeed delivers the headers of blocks that lost the fork choice

// (were not adopted as canonical) to subscribers — namely the PoW miner,

// which collects them as uncle candidates.

sideBlockFeed event.Feed

↗}

core-geth validation — +11 -1

| | | |---|---| | File | [`forkchoice.go`](https://github.com/etclabscore/core-geth/blob/v1.12.20/core/forkchoice.go) | | Symbol | `ForkChoice` | | Ref | `v1.12.20` |

--- a/core-geth/core/forkchoice.go
+++ b/etc/core/forkchoice_pow.go
@@ -4,7 +4,7 @@
 // offering fork choice during the eth1/2 merge phase, but also keep the compatibility
 // for all other proof-of-work networks.
 type ForkChoice struct {
-   chain consensus.ChainHeaderReader
+   chain ChainReader
    rand  *mrand.Rand

    // preserve is a helper function used in td fork choice.
@@ -12,4 +12,14 @@
    // local td is equal to the extern one. It can be nil for light
    // client
    preserve func(header *types.Header) bool
+
+   // reorgFilter is an optional callback that validates whether a reorg
+   // warranted by TD should actually be applied.  Returns nil if allowed,
+   // non-nil error if the reorg must be rejected.
+   reorgFilter func(current, extern *types.Header) error
+
+   // sideBlockFeed delivers the headers of blocks that lost the fork choice
+   // (were not adopted as canonical) to subscribers — namely the PoW miner,
+   // which collects them as uncle candidates.
+   sideBlockFeed event.Feed
 }

← MESS