fix accounts cache init API

nimbus/db/accounts_cache.nim

@@ -45,12 +45,15 @@ proc beginSavepoint*(ac: var AccountsCache): SavePoint {.gcsafe.}
 
 # The AccountsCache is modeled after TrieDatabase for it's transaction style
 proc init*(x: typedesc[AccountsCache], db: TrieDatabaseRef,
-           root: KeccakHash, pruneTrie: bool): AccountsCache =
+           root: KeccakHash, pruneTrie: bool = true): AccountsCache =
   result.db = db
   result.trie = initSecureHexaryTrie(db, root, pruneTrie)
   result.unrevertablyTouched = initHashSet[EthAddress]()
   discard result.beginSavepoint
 
+proc init*(x: typedesc[AccountsCache], db: TrieDatabaseRef, pruneTrie: bool = true): AccountsCache =
+  init(x, db, emptyRlpHash, pruneTrie)
+
 proc rootHash*(ac: AccountsCache): KeccakHash =
   # make sure all savepoint already committed
   doAssert(ac.savePoint.parentSavePoint.isNil)

tests/test_state_db.nim

@@ -141,5 +141,14 @@ proc stateDBMain*() =
       # state trie at all
       check ac.rootHash == rootHash
 
+    test "accounts cache code retrieval after persist called":
+      var ac = init(AccountsCache, acDB)
+      var addr2 = initAddr(2)
+      ac.setCode(addr2, code)
+      ac.persist()
+      check ac.getCode(addr2) == code      
+      let key = contractHashKey(hexary.keccak(code))      
+      check acDB.get(key.toOpenArray) == code
+            
 when isMainModule:
   stateDBMain()