optim: shallow copy block header in Context (cosmos#19966)

CHANGELOG.md

@@ -92,6 +92,7 @@ Every module contains its own CHANGELOG.md. Please refer to the module you are i
 * (types) [#18963](https://github.com/cosmos/cosmos-sdk/pull/18963) Swap out amino json encoding of `ABCIMessageLogs` for std lib json encoding
 * (x/auth) [#19651](https://github.com/cosmos/cosmos-sdk/pull/19651) Allow empty public keys in `GetSignBytesAdapter`.
 * (x/genutil) [#19735](https://github.com/cosmos/cosmos-sdk/pull/19735) Update genesis api to match new `appmodule.HasGenesis` interface.
+* (server) [#19966](https://github.com/cosmos/cosmos-sdk/pull/19966) Return BlockHeader by shallow copy in server Context.
 
 ### Bug Fixes
 

types/context.go

@@ -6,7 +6,6 @@ import (
 
 	abci "github.com/cometbft/cometbft/abci/types"
 	cmtproto "github.com/cometbft/cometbft/proto/tendermint/types"
-	"github.com/cosmos/gogoproto/proto"
 
 	"cosmossdk.io/core/comet"
 	"cosmossdk.io/core/header"
@@ -91,10 +90,9 @@ func (c Context) StreamingManager() storetypes.StreamingManager { return c.strea
 func (c Context) CometInfo() comet.Info                         { return c.cometInfo }
 func (c Context) HeaderInfo() header.Info                       { return c.headerInfo }
 
-// clone the header before returning
+// BlockHeader returns the header by value.
 func (c Context) BlockHeader() cmtproto.Header {
-	msg := proto.Clone(&c.header).(*cmtproto.Header)
-	return *msg
+	return c.header
 }
 
 // HeaderHash returns a copy of the header hash obtained during abci.RequestBeginBlock