PoW checking fixes

Author: vbuterin

ethereum/blocks.py

@@ -330,7 +330,7 @@ def seed(self):
             seed = utils.sha3(seed)
         return seed
 
-    def check_pow(self, db=None, nonce=None):
+    def check_pow(self, nonce=None, debugmode=False):
         """Check if the proof-of-work of the block is valid.
 
         :param nonce: if given the proof of work function will be evaluated
@@ -339,9 +339,6 @@ def check_pow(self, db=None, nonce=None):
         :returns: `True` or `False`
         """
         nonce = nonce or self.nonce
-        if db is None:
-            assert self.block is not None
-            db = self.block.db
         if len(self.mixhash) != 32 or len(self.nonce) != 8:
             raise ValueError("Bad mixhash or nonce length")
         # exclude mixhash and nonce
@@ -354,6 +351,11 @@ def check_pow(self, db=None, nonce=None):
         current_full_size = get_full_size(self.number)
         mining_output = hashimoto_light(current_full_size, cache, header_hash, nonce)
         diff = self.difficulty
+        if debugmode:
+            print 'Mining hash: %s' % encode_hex(header_hash)
+            print 'Seed: %s' % encode_hex(seed)
+            print 'Mixhash: %s' % encode_hex(mining_output['mix digest'])
+            print 'Result: %s' % encode_hex(mining_output['result'])
         if mining_output['mix digest'] != self.mixhash:
             return False
         return utils.big_endian_to_int(mining_output['result']) <= 2**256 / (diff or 1)
@@ -552,7 +554,7 @@ def __init__(self, header, transaction_list=[], uncles=[], db=None,
             raise ValueError("State Merkle root of block %r not found in "
                              "database" % self)
         if (not self.is_genesis() and self.nonce and
-                                  not self.header.check_pow(self.db)):
+                                  not self.header.check_pow()):
             raise ValueError("PoW check failed")
         self.db.put('validated:'+self.hash, '1')
 
@@ -673,7 +675,7 @@ def validate_uncles(self, db=None):
         ineligible.extend([b.header for b in ancestor_chain])
         eligible_ancestor_hashes = [x.hash for x in ancestor_chain[2:]]
         for uncle in self.uncles:
-            if not uncle.check_pow(db=db):
+            if not uncle.check_pow():
                 return False
             if uncle.prevhash not in eligible_ancestor_hashes:
                 log.error("Uncle does not have a valid ancestor", block=self,

ethereum/chain.py

@@ -158,7 +158,8 @@ def _update_head(self, block):
                     uncles.discard(self.get(u))
             if blk.has_parent():
                 blk = blk.get_parent()
-        uncles = list(uncles)
+        # TODO: make this work
+        uncles = list(uncles)[:0]
         ts = max(int(time.time()), block.timestamp + 1)
         self.head_candidate = blocks.Block.init_from_parent(block, coinbase=self._coinbase,
                                                             timestamp=ts, uncles=uncles)

ethereum/tests/benchmark_db.py

@@ -8,13 +8,15 @@ def benchmark(size):
         t.update(utils.sha3('k'+str(i)), utils.sha3('v'+str(i)))
     sz = sum([len(v) for k, v in t.db.db.items()])
     nsz = []
+    ldb = db.ListeningDB(t.db.db)
     for i in range(min(size, 100)):
-        ldb = db.ListeningDB(t.db.db)
+        ldb2 = db.ListeningDB(ldb)
         odb = t.db
-        t.db = ldb
+        t.db = ldb2
         t.get(utils.sha3('k'+str(i)))
-        nsz.append(sum([len(v) for k, v in ldb.kv.items()]))
+        nsz.append(sum([len(v) for k, v in ldb2.kv.items()]))
         t.db = odb
-    print sz, sum(nsz) // len(nsz)
+    ldbsz = sum([len(v) for k, v in ldb.kv.items()])
+    print sz, sum(nsz) // len(nsz), ldbsz
 
 benchmark(int(sys.argv[1]) if len(sys.argv) > 1 else 1000)