Closely match Core's (de-)serialization; remove old test case

Author: Bob McElrath

bitcoin/core/__init__.py

@@ -399,13 +399,19 @@ def __init__(self, vin=(), vout=(), nLockTime=0, nVersion=1, witness=CTxWitness(
 
     @classmethod
     def stream_deserialize(cls, f):
+        """Deserialize a transaction.  This implementation corresponds to
+            Bitcoin's SerializeTransaction() and consensus behavior.  Note that
+            Bitcoin's DecodeHexTx() also has the option to attempt deserializing
+            as a non-witness transaction first, falling back to the consensus
+            behavior if it fails.  The difference lies in transactions which
+            have zero inputs: they are invalid but may be (de-)serialized anyway
+            for the purpose of signing them and adding inputs.  If the behavior
+            of DecodeHexTx() is needed it could be added, but not here.  """
         nVersion = struct.unpack(b"<i", ser_read(f,4))[0]
         pos = f.tell()
         markerbyte = struct.unpack(b'B', ser_read(f, 1))[0]
-        if markerbyte == 0:
-            flagbyte = struct.unpack(b'B', ser_read(f, 1))[0]
-            if flagbyte != 1:
-                raise DeserializationFormatError
+        flagbyte = struct.unpack(b'B', ser_read(f, 1))[0]
+        if markerbyte == 0 and flagbyte == 1:
             vin = VectorSerializer.stream_deserialize(CTxIn, f)
             vout = VectorSerializer.stream_deserialize(CTxOut, f)
             wit = CTxWitness(tuple(0 for dummy in range(len(vin))))
@@ -421,21 +427,18 @@ def stream_deserialize(cls, f):
 
 
     def stream_serialize(self, f):
+        f.write(struct.pack(b"<i", self.nVersion))
         if not self.wit.is_null():
-            if len(self.wit.vtxinwit) != len(self.vin):
-                raise SerializationMissingWitnessError
-            f.write(struct.pack(b"<i", self.nVersion))
+            assert(len(self.wit.vtxinwit) <= len(self.vin))
             f.write(b'\x00') # Marker
             f.write(b'\x01') # Flag
             VectorSerializer.stream_serialize(CTxIn, self.vin, f)
             VectorSerializer.stream_serialize(CTxOut, self.vout, f)
             self.wit.stream_serialize(f)
-            f.write(struct.pack(b"<I", self.nLockTime))
         else:
-            f.write(struct.pack(b"<i", self.nVersion))
             VectorSerializer.stream_serialize(CTxIn, self.vin, f)
             VectorSerializer.stream_serialize(CTxOut, self.vout, f)
-            f.write(struct.pack(b"<I", self.nLockTime))
+        f.write(struct.pack(b"<I", self.nLockTime))
 
     def is_coinbase(self):
         return len(self.vin) == 1 and self.vin[0].prevout.is_null()

bitcoin/core/serialize.py

@@ -55,10 +55,6 @@ class SerializationTruncationError(SerializationError):
     Thrown by deserialize() and stream_deserialize()
     """
 
-class SerializationMissingWitnessError(SerializationError):
-    """Missing witness data when serializing a segregated witness transaction
-    """
-
 class DeserializationExtraDataError(SerializationError):
     """Deserialized data had extra data at the end
 
@@ -71,11 +67,6 @@ def __init__(self, msg, obj, padding):
         self.obj = obj
         self.padding = padding
 
-class DeserializationFormatError(SerializationError):
-    """Deserialized data does not have the correct marker or flag bytes for a
-        segwit serialization
-    """
-
 def ser_read(f, n):
     """Read from a stream safely
 
@@ -371,9 +362,7 @@ def uint256_to_shortstr(u):
         'Hash160',
         'SerializationError',
         'SerializationTruncationError',
-        'SerializationMissingWitnessError',
         'DeserializationExtraDataError',
-        'DeserializationFormatError',
         'ser_read',
         'Serializable',
         'ImmutableSerializable',

bitcoin/tests/data/tx_invalid.json

@@ -23,11 +23,6 @@
 [[["0000000000000000000000000000000000000000000000000000000000000100", 0, "HASH160 0x14 0x7a052c840ba73af26755de42cf01cc9e0a49fef0 EQUAL"]],
 "010000000100010000000000000000000000000000000000000000000000000000000000000000000009085768617420697320ffffffff010000000000000000015100000000", true],
 
-["Tests for CheckTransaction()"],
-["No inputs"],
-[[["0000000000000000000000000000000000000000000000000000000000000100", 0, "HASH160 0x14 0x7a052c840ba73af26755de42cf01cc9e0a49fef0 EQUAL"]],
-"0100000000010000000000000000015100000000", true],
-
 ["No outputs"],
 [[["0000000000000000000000000000000000000000000000000000000000000100", 0, "HASH160 0x14 0x05ab9e14d983742513f0f451e105ffb4198d1dd4 EQUAL"]],
 "01000000010001000000000000000000000000000000000000000000000000000000000000000000006d483045022100f16703104aab4e4088317c862daec83440242411b039d14280e03dd33b487ab802201318a7be236672c5c56083eb7a5a195bc57a40af7923ff8545016cd3b571e2a601232103c40e5d339df3f30bf753e7e04450ae4ef76c9e45587d1d993bdc4cd06f0651c7acffffffff0000000000", true],