cmd, core: resolve scheme from a read-write database (#28313)

* cmd, core: resolve scheme from a read-write database

* cmd, core, eth: move the scheme check in the ethereum constructor

* cmd/geth: dump should in ro mode

* cmd: reverts

eth/ethconfig/config.go

@@ -27,7 +27,6 @@ import (
 	"github.com/ethereum/go-ethereum/consensus/clique"
 	"github.com/ethereum/go-ethereum/consensus/ethash"
 	"github.com/ethereum/go-ethereum/core"
-	"github.com/ethereum/go-ethereum/core/rawdb"
 	"github.com/ethereum/go-ethereum/core/txpool/blobpool"
 	"github.com/ethereum/go-ethereum/core/txpool/legacypool"
 	"github.com/ethereum/go-ethereum/eth/downloader"
@@ -64,7 +63,6 @@ var Defaults = Config{
 	TxLookupLimit:      2350000,
 	TransactionHistory: 2350000,
 	StateHistory:       params.FullImmutabilityThreshold,
-	StateScheme:        rawdb.HashScheme,
 	LightPeers:         100,
 	DatabaseCache:      512,
 	TrieCleanCache:     154,
@@ -105,7 +103,11 @@ type Config struct {
 	TxLookupLimit      uint64 `toml:",omitempty"` // The maximum number of blocks from head whose tx indices are reserved.
 	TransactionHistory uint64 `toml:",omitempty"` // The maximum number of blocks from head whose tx indices are reserved.
 	StateHistory       uint64 `toml:",omitempty"` // The maximum number of blocks from head whose state histories are reserved.
-	StateScheme        string `toml:",omitempty"` // State scheme used to store ethereum state and merkle trie nodes on top
+
+	// State scheme represents the scheme used to store ethereum states and trie
+	// nodes on top. It can be 'hash', 'path', or none which means use the scheme
+	// consistent with persistent state.
+	StateScheme string `toml:",omitempty"`
 
 	// RequiredBlocks is a set of block number -> hash mappings which must be in the
 	// canonical chain of all remote peers. Setting the option makes geth verify the