Don't apply geth poa field remapping if result is None

Author: kclowes

newsfragments/2064.bugfix.rst

@@ -0,0 +1 @@
+Fix bug in geth PoA middleware where a ``None`` response should throw a ``BlockNotFound`` error, but was instead throwing an ``AttributeError``

tests/core/eth-module/test_poa.py

@@ -1,6 +1,7 @@
 import pytest
 
 from web3.exceptions import (
+    BlockNotFound,
     ExtraDataLengthError,
 )
 from web3.middleware import (
@@ -37,3 +38,13 @@ def test_geth_proof_of_authority(web3):
     block = web3.eth.get_block('latest')
     assert 'extraData' not in block
     assert block.proofOfAuthorityData == b'\xff' * 33
+
+
+def test_returns_none_response(web3):
+    return_none_response = construct_fixture_middleware({
+        'eth_getBlockByNumber': None,
+    })
+    web3.middleware_onion.inject(geth_poa_middleware, layer=0)
+    web3.middleware_onion.inject(return_none_response, layer=0)
+    with pytest.raises(BlockNotFound):
+        web3.eth.get_block(100000000000)

web3/middleware/geth_poa.py

@@ -1,20 +1,25 @@
 from eth_utils.curried import (
+    apply_formatter_if,
     apply_formatters_to_dict,
     apply_key_map,
+    is_null,
 )
 from eth_utils.toolz import (
+    complement,
     compose,
 )
 from hexbytes import (
     HexBytes,
 )
 
+from web3._utils.rpc_abi import (
+    RPC,
+)
 from web3.middleware.formatting import (
     construct_formatting_middleware,
 )
-from web3.types import (
-    RPCEndpoint,
-)
+
+is_not_null = complement(is_null)
 
 remap_geth_poa_fields = apply_key_map({
     'extraData': 'proofOfAuthorityData',
@@ -28,7 +33,7 @@
 
 geth_poa_middleware = construct_formatting_middleware(
     result_formatters={
-        RPCEndpoint("eth_getBlockByHash"): geth_poa_cleanup,
-        RPCEndpoint("eth_getBlockByNumber"): geth_poa_cleanup,
+        RPC.eth_getBlockByHash: apply_formatter_if(is_not_null, geth_poa_cleanup),
+        RPC.eth_getBlockByNumber: apply_formatter_if(is_not_null, geth_poa_cleanup),
     },
 )