all: on-chain oracle checkpoint syncing (#19543)

* all: implement simple checkpoint syncing

cmd, les, node: remove callback mechanism

cmd, node: remove callback definition

les: simplify the registrar

les: expose checkpoint rpc services in the light client

les, light: don't store untrusted receipt

cmd, contracts, les: discard stale checkpoint

cmd, contracts/registrar: loose restriction of registeration

cmd, contracts: add replay-protection

all: off-chain multi-signature contract

params: deploy checkpoint contract for rinkeby

cmd/registrar: add raw signing mode for registrar

cmd/registrar, contracts/registrar, les: fixed messages

* cmd/registrar, contracts/registrar: fix lints

* accounts/abi/bind, les: address comments

* cmd, contracts, les, light, params: minor checkpoint sync cleanups

* cmd, eth, les, light: move checkpoint config to config file

* cmd, eth, les, params: address comments

* eth, les, params: address comments

* cmd: polish up the checkpoint admin CLI

* cmd, contracts, params: deploy new version contract

* cmd/checkpoint-admin: add another flag for clef mode signing

* cmd, contracts, les: rename and regen checkpoint oracle with abigen

1 files changed, 4 insertions, 3 deletions

diff --git a/core/chain_indexer.go b/core/chain_indexer.go
index 26538260c..80062714a 100644
--- a/core/chain_indexer.go
+++ b/core/chain_indexer.go
@@ -128,12 +128,13 @@ func (c *ChainIndexer) AddCheckpoint(section uint64, shead common.Hash) {
 	c.lock.Lock()
 	defer c.lock.Unlock()
 
+	// Short circuit if the given checkpoint is below than local's.
+	if c.checkpointSections >= section+1 || section < c.storedSections {
+		return
+	}
 	c.checkpointSections = section + 1
 	c.checkpointHead = shead
 
-	if section < c.storedSections {
-		return
-	}
 	c.setSectionHead(section, shead)
 	c.setValidSections(section + 1)
 }