core, tests: fix tests and special recovery case

core/blockchain.go

@@ -279,14 +279,15 @@ func NewBlockChain(db ethdb.Database, cacheConfig *CacheConfig, chainConfig *par
 		return nil, err
 	}
 	// Make sure the state associated with the block is available
-	head := bc.CurrentBlock()
+	head, recoverSnapshot := bc.CurrentBlock(), false
 	if _, err := state.New(head.Root(), bc.stateCache, bc.snaps); err != nil {
 		// Head state is missing, before the state recovery, find out the
 		// disk layer point of snapshot(if it's enabled). Make sure the
 		// rewound point is lower then disk layer.
 		var diskRoot common.Hash
 		if bc.cacheConfig.SnapshotLimit > 0 {
 			diskRoot = rawdb.ReadSnapshotRoot(bc.db)
+			recoverSnapshot = true
 		}
 		log.Warn("Head state missing, repairing", "number", head.Number(), "hash", head.Hash())
 		if diskRoot != (common.Hash{}) {
@@ -357,7 +358,7 @@ func NewBlockChain(db ethdb.Database, cacheConfig *CacheConfig, chainConfig *par
 	}
 	// Load any existing snapshot, regenerating it if loading failed
 	if bc.cacheConfig.SnapshotLimit > 0 {
-		bc.snaps = snapshot.New(bc.db, bc.stateCache.TrieDB(), bc.cacheConfig.SnapshotLimit, bc.CurrentBlock().Root(), !bc.cacheConfig.SnapshotWait)
+		bc.snaps = snapshot.New(bc.db, bc.stateCache.TrieDB(), bc.cacheConfig.SnapshotLimit, bc.CurrentBlock().Root(), !bc.cacheConfig.SnapshotWait, recoverSnapshot)
 	}
 	// Take ownership of this particular state
 	go bc.update()
@@ -496,10 +497,9 @@ func (bc *BlockChain) setHead(head uint64, onDelete func(block *types.Block, can
 						} else {
 							log.Trace("Rewind passed pivot, aiming genesis", "number", newHeadBlock.NumberU64(), "hash", newHeadBlock.Hash(), "pivot", *pivot)
 							newHeadBlock = bc.genesisBlock
-							canStop = true
 						}
 					}
-					if canStop {
+					if canStop || newHeadBlock.NumberU64() == 0 {
 						log.Debug("Rewound to block with state", "number", newHeadBlock.NumberU64(), "hash", newHeadBlock.Hash())
 						break
 					}

core/blockchain_repair_test.go

@@ -21,6 +21,7 @@
 package core
 
 import (
+	"fmt"
 	"io/ioutil"
 	"math/big"
 	"os"
@@ -1556,7 +1557,7 @@ func TestLongReorgedFastSyncingDeepRepair(t *testing.T) {
 func testRepair(t *testing.T, tt *rewindTest) {
 	// It's hard to follow the test case, visualize the input
 	//log.Root().SetHandler(log.LvlFilterHandler(log.LvlTrace, log.StreamHandler(os.Stderr, log.TerminalFormat(true))))
-	//fmt.Println(tt.dump(true))
+	fmt.Println(tt.dump(true))
 
 	// Create a temporary persistent database
 	datadir, err := ioutil.TempDir("", "")
@@ -1573,10 +1574,15 @@ func testRepair(t *testing.T, tt *rewindTest) {
 
 	// Initialize a fresh chain
 	var (
-		genesis = new(Genesis).MustCommit(db)
-		engine  = ethash.NewFullFaker()
+		genesis     = new(Genesis).MustCommit(db)
+		engine      = ethash.NewFullFaker()
+		cacheConfig = defaultCacheConfig
 	)
-	chain, err := NewBlockChain(db, nil, params.AllEthashProtocolChanges, engine, vm.Config{}, nil, nil)
+	if !tt.enableSnapshot {
+		cacheConfig.SnapshotLimit = 0
+		cacheConfig.SnapshotWait = false
+	}
+	chain, err := NewBlockChain(db, cacheConfig, params.AllEthashProtocolChanges, engine, vm.Config{}, nil, nil)
 	if err != nil {
 		t.Fatalf("Failed to create chain: %v", err)
 	}

core/blockchain_sethead_test.go

@@ -37,6 +37,7 @@ import (
 
 // rewindTest is a test case for chain rollback upon user request.
 type rewindTest struct {
+	enableSnapshot  bool    // Flag whether the snapshot is enabled
 	canonicalBlocks int     // Number of blocks to generate for the canonical chain (heavier)
 	sidechainBlocks int     // Number of blocks to generate for the side chain (lighter)
 	freezeThreshold uint64  // Block number until which to move things into the freezer
@@ -55,7 +56,8 @@ type rewindTest struct {
 func (tt *rewindTest) dump(crash bool) string {
 	buffer := new(strings.Builder)
 
-	fmt.Fprint(buffer, "Chain:\n  G")
+	fmt.Fprint(buffer, fmt.Sprintf("Chain<snapshot = %t>:", tt.enableSnapshot))
+	fmt.Fprint(buffer, "\n  G")
 	for i := 0; i < tt.canonicalBlocks; i++ {
 		fmt.Fprintf(buffer, "->C%d", i+1)
 	}
@@ -1747,7 +1749,7 @@ func TestLongReorgedFastSyncingDeepSetHead(t *testing.T) {
 func testSetHead(t *testing.T, tt *rewindTest) {
 	// It's hard to follow the test case, visualize the input
 	//log.Root().SetHandler(log.LvlFilterHandler(log.LvlTrace, log.StreamHandler(os.Stderr, log.TerminalFormat(true))))
-	//fmt.Println(tt.dump(false))
+	fmt.Println(tt.dump(false))
 
 	// Create a temporary persistent database
 	datadir, err := ioutil.TempDir("", "")
@@ -1764,10 +1766,15 @@ func testSetHead(t *testing.T, tt *rewindTest) {
 
 	// Initialize a fresh chain
 	var (
-		genesis = new(Genesis).MustCommit(db)
-		engine  = ethash.NewFullFaker()
+		genesis     = new(Genesis).MustCommit(db)
+		engine      = ethash.NewFullFaker()
+		cacheConfig = defaultCacheConfig
 	)
-	chain, err := NewBlockChain(db, nil, params.AllEthashProtocolChanges, engine, vm.Config{}, nil, nil)
+	if !tt.enableSnapshot {
+		cacheConfig.SnapshotLimit = 0
+		cacheConfig.SnapshotWait = false
+	}
+	chain, err := NewBlockChain(db, cacheConfig, params.AllEthashProtocolChanges, engine, vm.Config{}, nil, nil)
 	if err != nil {
 		t.Fatalf("Failed to create chain: %v", err)
 	}

core/state/snapshot/journal.go

@@ -143,7 +143,7 @@ func loadAndParseJournal(db ethdb.KeyValueStore, base *diskLayer) (snapshot, jou
 }
 
 // loadSnapshot loads a pre-existing state snapshot backed by a key-value store.
-func loadSnapshot(diskdb ethdb.KeyValueStore, triedb *trie.Database, cache int, root common.Hash) (snapshot, error) {
+func loadSnapshot(diskdb ethdb.KeyValueStore, triedb *trie.Database, cache int, root common.Hash, recovery bool) (snapshot, error) {
 	// Retrieve the block number and hash of the snapshot, failing if no snapshot
 	// is present in the database (or crashed mid-update).
 	baseRoot := rawdb.ReadSnapshotRoot(diskdb)
@@ -175,9 +175,16 @@ func loadSnapshot(diskdb ethdb.KeyValueStore, triedb *trie.Database, cache int,
 	// which is below the snapshot. In this case the snapshot can be recovered
 	// by re-executing blocks but right now it's unavailable.
 	if head := snapshot.Root(); head != root {
-		if legacy {
+		// If it's legacy snapshot, or it's new-format snapshot but
+		// it's not in recovery mode, returns the error here for
+		// rebuilding the entire snapshot forcibly.
+		if legacy || !recovery {
 			return nil, fmt.Errorf("head doesn't match snapshot: have %#x, want %#x", head, root)
 		}
+		// It's in snapshot recovery, the assumption is held that
+		// the disk layer is higher than chain head. It can be
+		// eventually recovered when the chain head is beyond the
+		// disk layer.
 		log.Warn("Snapshot is not continous with chain", "snaproot", head, "chainroot", root)
 	}
 	// Everything loaded correctly, resume any suspended operations

core/state/snapshot/snapshot.go

@@ -172,8 +172,9 @@ type Tree struct {
 // If the snapshot is missing or the disk layer is broken, the entire is deleted
 // and will be reconstructed from scratch based on the tries in the key-value
 // store, on a background thread. If the memory layers from the journal is not
-// continuous with disk layer or the journal is missing, all diffs will be discarded.
-func New(diskdb ethdb.KeyValueStore, triedb *trie.Database, cache int, root common.Hash, async bool) *Tree {
+// continuous with disk layer or the journal is missing, all diffs will be discarded
+// iff it's in "recovery" mode, otherwise rebuild is mandatory.
+func New(diskdb ethdb.KeyValueStore, triedb *trie.Database, cache int, root common.Hash, async bool, recovery bool) *Tree {
 	// Create a new, empty snapshot tree
 	snap := &Tree{
 		diskdb: diskdb,
@@ -185,7 +186,7 @@ func New(diskdb ethdb.KeyValueStore, triedb *trie.Database, cache int, root comm
 		defer snap.waitBuild()
 	}
 	// Attempt to load a previously persisted snapshot and rebuild one if failed
-	head, err := loadSnapshot(diskdb, triedb, cache, root)
+	head, err := loadSnapshot(diskdb, triedb, cache, root, recovery)
 	if err != nil {
 		log.Warn("Failed to load snapshot, regenerating", "err", err)
 		snap.Rebuild(root)

tests/state_test_util.go

@@ -235,7 +235,7 @@ func MakePreState(db ethdb.Database, accounts core.GenesisAlloc, snapshotter boo
 
 	var snaps *snapshot.Tree
 	if snapshotter {
-		snaps = snapshot.New(db, sdb.TrieDB(), 1, root, false)
+		snaps = snapshot.New(db, sdb.TrieDB(), 1, root, false, false)
 	}
 	statedb, _ = state.New(root, sdb, snaps)
 	return snaps, statedb