Merge pull request #11 from iamdefinitelyahuman/v1.0.1

V1.1.0

CHANGELOG.md

@@ -7,6 +7,13 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased](https://github.com/iamdefinitelyahuman/eth-event)
 
+## [1.1.0](https://github.com/iamdefinitelyahuman/eth-event/releases/tag/v1.1.0) - 2020-05-30
+### Added
+- Decode events when the ABI contains indexed values but the log has None
+
+### Changed
+- More expressive error messages when an event cannot be decoded from an incorrect number of topics
+
 ## [1.0.0](https://github.com/iamdefinitelyahuman/eth-event/releases/tag/v1.0.0) - 2020-04-21
 ### Added
 - Anonymous and undecodable events can be returned without raising with the `allow_undecoded` kwarg

eth_event/main.py

@@ -3,7 +3,7 @@
 from typing import Dict, List
 
 from eth_abi import decode_abi, decode_single
-from eth_abi.exceptions import InsufficientDataBytes
+from eth_abi.exceptions import InsufficientDataBytes, NonEmptyPaddingBytes
 from eth_hash.auto import keccak
 from hexbytes import HexBytes
 
@@ -256,39 +256,67 @@ def _params(abi_params: List) -> List:
 
 
 def _decode(inputs: List, topics: List, data: str) -> List:
+    indexed_count = len([i for i in inputs if i["indexed"]])
+
+    if indexed_count and not topics:
+        # special case - if the ABI has indexed values but the log does not,
+        # we should still be able to decode the data
+        unindexed_types = inputs
+
+    else:
+        if indexed_count < len(topics):
+            raise EventError(
+                "Event log does not contain enough topics for the given ABI - this"
+                " is usually because an event argument is not marked as indexed"
+            )
+        if indexed_count > len(topics):
+            raise EventError(
+                "Event log contains more topics than expected for the given ABI - this is"
+                " usually because an event argument is incorrectly marked as indexed"
+            )
+        unindexed_types = [i for i in inputs if not i["indexed"]]
+
+    # decode the unindexed event data
     try:
-        types = _params([i for i in inputs if not i["indexed"]])
+        unindexed_types = _params(unindexed_types)
     except (KeyError, TypeError):
         raise ABIError("Invalid ABI")
 
-    if types and data == "0x":
-        data += "0" * (len(types) * 64)
+    if unindexed_types and data == "0x":
+        length = len(unindexed_types) * 32
+        data = f"0x{bytes(length).hex()}"
 
     try:
-        decoded = list(decode_abi(types, HexBytes(data)))[::-1]
+        decoded = list(decode_abi(unindexed_types, HexBytes(data)))[::-1]
     except InsufficientDataBytes:
-        raise EventError("Insufficient event data")
+        raise EventError("Event data has insufficient length")
+    except NonEmptyPaddingBytes:
+        raise EventError("Malformed data field in event log")
     except OverflowError:
         raise EventError("Cannot decode event due to overflow error")
 
+    # decode the indexed event data and create the returned dict
     topics = topics[::-1]
     result = []
     for i in inputs:
         result.append({"name": i["name"], "type": i["type"]})
+
         if "components" in i:
             result[-1]["components"] = i["components"]
-        if i["indexed"]:
-            if not topics:
-                raise EventError("Insufficient event data")
+
+        if topics and i["indexed"]:
             encoded = HexBytes(topics.pop())
             try:
                 value = decode_single(i["type"], encoded)
             except (InsufficientDataBytes, OverflowError):
+                # an array or other data type that uses multiple slots
                 result[-1].update({"value": encoded.hex(), "decoded": False})
                 continue
         else:
             value = decoded.pop()
+
         if isinstance(value, bytes):
+            # converting to `HexBytes` first ensures the leading `0x`
             value = HexBytes(value).hex()
         result[-1].update({"value": value, "decoded": True})
 

setup.cfg

@@ -1,5 +1,5 @@
 [bumpversion]
-current_version = 1.0.0
+current_version = 1.1.0
 
 [bumpversion:file:setup.py]
 
@@ -21,3 +21,4 @@ use_parentheses = True
 
 [tool:pytest]
 addopts = --cov=eth_event/ --cov-report term --cov-report xml
+

setup.py

@@ -7,7 +7,7 @@
 
 setup(
     name="eth-event",
-    version="1.0.0",  # do not edit directly, use bumpversion
+    version="1.1.0",  # do not edit directly, use bumpversion
     license="MIT",
     description="Ethereum event decoder and topic generator",
     long_description=long_description,

tests/test_incorrect_topics.py

@@ -0,0 +1,92 @@
+import pytest
+from hexbytes import HexBytes
+
+from eth_event import EventError, decode_log, get_topic_map
+
+abi_no_indexes = {
+    "anonymous": False,
+    "inputs": [
+        {"indexed": False, "name": "sender", "type": "address"},
+        {"indexed": False, "name": "receiver", "type": "address"},
+        {"indexed": False, "name": "value", "type": "uint256"},
+    ],
+    "name": "Transfer",
+    "type": "event",
+}
+
+abi_two_indexes = {
+    "anonymous": False,
+    "inputs": [
+        {"indexed": True, "name": "sender", "type": "address"},
+        {"indexed": True, "name": "receiver", "type": "address"},
+        {"indexed": False, "name": "value", "type": "uint256"},
+    ],
+    "name": "Transfer",
+    "type": "event",
+}
+
+log_no_indexes = {
+    "logIndex": 0,
+    "transactionIndex": 0,
+    "transactionHash": HexBytes(
+        "0xe1997c46647f74afdffb1473930f90b0ebf6902a75dda0d0c3cbd6d1b57a91e1"
+    ),
+    "blockHash": HexBytes("0xf571bead3dcf424322ddd02fa7fc0496e06386bef4029de55e2255dee4945cdf"),
+    "blockNumber": 4,
+    "address": "0xE7eD6747FaC5360f88a2EFC03E00d25789F69291",
+    "data": "0x00000000000000000000000066ab6d9362d4f35596279692f0251db63516587100000000000000000000000066ab6d9362d4f35596279692f0251db6351658710000000000000000000000000000000000000000000000000000000000002710",  # noqa: E501
+    "topics": [HexBytes("0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef")],
+    "type": "mined",
+}
+
+log_one_index = {
+    "logIndex": 0,
+    "transactionIndex": 0,
+    "transactionHash": HexBytes(
+        "0xe6eba721271cedb7a492c513d5dfedab73cc54f1a5a337fb027d23f523cada49"
+    ),
+    "blockHash": HexBytes("0x764e1736dc9cba192b2ebf2911abcad9168d4db35850a678600637f5a6de27ed"),
+    "blockNumber": 4,
+    "address": "0xE7eD6747FaC5360f88a2EFC03E00d25789F69291",
+    "data": "0x00000000000000000000000066ab6d9362d4f35596279692f0251db6351658710000000000000000000000000000000000000000000000000000000000002710",  # noqa: E501
+    "topics": [
+        HexBytes("0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef"),
+        HexBytes("0x00000000000000000000000033a4622b82d4c04a53e170c638b944ce27cffce3"),
+    ],
+    "type": "mined",
+}
+
+log_two_indexes = {
+    "logIndex": 0,
+    "transactionIndex": 0,
+    "transactionHash": HexBytes(
+        "0xe6eba721271cedb7a492c513d5dfedab73cc54f1a5a337fb027d23f523cada49"
+    ),
+    "blockHash": HexBytes("0x764e1736dc9cba192b2ebf2911abcad9168d4db35850a678600637f5a6de27ed"),
+    "blockNumber": 4,
+    "address": "0xE7eD6747FaC5360f88a2EFC03E00d25789F69291",
+    "data": "0x0000000000000000000000000000000000000000000000000000000000002710",
+    "topics": [
+        HexBytes("0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef"),
+        HexBytes("0x00000000000000000000000066ab6d9362d4f35596279692f0251db635165871"),
+        HexBytes("0x00000000000000000000000033a4622b82d4c04a53e170c638b944ce27cffce3"),
+    ],
+    "type": "mined",
+}
+
+
+def test_no_topics_in_log():
+    topic_map = get_topic_map([abi_two_indexes])
+    decode_log(log_no_indexes, topic_map)
+
+
+def test_too_many_log_topics():
+    topic_map = get_topic_map([abi_no_indexes])
+    with pytest.raises(EventError, match="does not contain enough topics"):
+        decode_log(log_two_indexes, topic_map)
+
+
+def test_insufficient_log_topics():
+    topic_map = get_topic_map([abi_two_indexes])
+    with pytest.raises(EventError, match="more topics than expected"):
+        decode_log(log_one_index, topic_map)