perf(consensus/blockstore): Remove validate basic call from LoadBlock…

…Meta (backport cometbft#2964) (cometbft#2998)

Our gossip block parts routine calls `Blockstore.LoadBlockMeta` (as do
things in blocksync). This currently takes some time due to
ValidateBasic:

![image](https://github.com/cometbft/cometbft/assets/6440154/2f4471b0-0744-44de-ab94-4a9a4596712c)

However note that we only save validated data to the blockstore. We only
do it in:
- Commit:
https://github.com/cometbft/cometbft/blob/main/internal/consensus/state.go#L1867
- Blocksync after validation:
https://github.com/cometbft/cometbft/blob/main/internal/consensus/state.go#L1867

Hence the validate basic time is wasted.

This should eventually just go to an LRU cache to even avoid the proto
unmarshalling (as should ~everything in blockstore) but we want this
anyway to reduce the computational overhead,

WRT live consensus, in main this only helps with catchup for live
syncing nodes, I haven't checked on v0.47.x, but the cpuprofile suggests
it may help with active block gossip time as well?

---

#### PR checklist

- [x] Tests written/updated
- [x] Changelog entry added in `.changelog` (we use
[unclog](https://github.com/informalsystems/unclog) to manage our
changelog)
- [x] Updated relevant documentation (`docs/` or `spec/`) and code
comments
- [x] Title follows the [Conventional
Commits](https://www.conventionalcommits.org/en/v1.0.0/) spec
<hr>This is an automatic backport of pull request cometbft#2964 done by
[Mergify](https://mergify.com).

---------

Co-authored-by: Dev Ojha <ValarDragon@users.noreply.github.com>
Co-authored-by: Anton Kaliaev <anton.kalyaev@gmail.com>

.changelog/unreleased/improvements/2964-skip-revalidation-of-blockstore-LoadBlockFromMeta-.md

@@ -0,0 +1,2 @@
+- `[blockstore]` Remove a redundant `Header.ValidateBasic` call in `LoadBlockMeta`, 75% reducing this time.
+  ([\#2964](https://github.com/cometbft/cometbft/pull/2964))

store/store.go

@@ -192,7 +192,7 @@ func (bs *BlockStore) LoadBlockMeta(height int64) *types.BlockMeta {
 		panic(fmt.Errorf("unmarshal to cmtproto.BlockMeta: %w", err))
 	}
 
-	blockMeta, err := types.BlockMetaFromProto(pbbm)
+	blockMeta, err := types.BlockMetaFromTrustedProto(pbbm)
 	if err != nil {
 		panic(fmt.Errorf("error from proto blockMeta: %w", err))
 	}

types/block_meta.go

@@ -41,6 +41,14 @@ func (bm *BlockMeta) ToProto() *cmtproto.BlockMeta {
 }
 
 func BlockMetaFromProto(pb *cmtproto.BlockMeta) (*BlockMeta, error) {
+	bm, err := BlockMetaFromTrustedProto(pb)
+	if err != nil {
+		return nil, err
+	}
+	return bm, bm.ValidateBasic()
+}
+
+func BlockMetaFromTrustedProto(pb *cmtproto.BlockMeta) (*BlockMeta, error) {
 	if pb == nil {
 		return nil, errors.New("blockmeta is empty")
 	}
@@ -62,7 +70,7 @@ func BlockMetaFromProto(pb *cmtproto.BlockMeta) (*BlockMeta, error) {
 	bm.Header = h
 	bm.NumTxs = int(pb.NumTxs)
 
-	return bm, bm.ValidateBasic()
+	return bm, nil
 }
 
 // ValidateBasic performs basic validation.

types/block_meta_test.go

@@ -34,7 +34,7 @@ func TestBlockMeta_ToProto(t *testing.T) {
 		t.Run(tt.testName, func(t *testing.T) {
 			pb := tt.bm.ToProto()
 
-			bm, err := BlockMetaFromProto(pb)
+			bm, err := BlockMetaFromTrustedProto(pb)
 
 			if !tt.expErr {
 				require.NoError(t, err, tt.testName)