Uniswap v3 valuation and swaps on Base (#255)

- Add Multicall3 support in `multicall_batcher` module
- Add `SwapRouter02` support on Base for doing Uniswap v3 swaps
- Add Uniswap V3 quoter for the valuation
- Add `buy_tokens()` helper to buy multiple tokens once, automatically look up best routes
- Refactor things around

.gitignore

@@ -29,4 +29,6 @@ docs/source/tutorials/aave.json
 contracts/aave-v3-deploy/hardhat-deployment-export.json
 
 # pyenv local
-.python-version
+.python-version
+
+contracts/lagoon-v0

CHANGELOG.md

@@ -1,3 +1,10 @@
+# Current
+
+- Add Multicall3 support in `multicall_batcher` module
+- Add `SwapRouter02` support on Base for doing Uniswap v3 swaps
+- Add Uniswap V3 quoter for the valuation
+- Add `buy_tokens()` helper to buy multiple tokens once, automatically look up best routes
+
 # 0.27
 
 - Add: Support for [Velvet Capital vaults](https://www.velvet.capital/)

eth_defi/abi.py

@@ -11,7 +11,7 @@
 import re
 from functools import lru_cache
 from pathlib import Path
-from typing import Optional, Sequence, Type, Union
+from typing import Optional, Sequence, Type, Union, Any
 
 import eth_abi
 from eth_abi import decode
@@ -27,12 +27,20 @@
 # Cache loaded ABI files in-process memory for speedup
 from web3.datastructures import AttributeDict
 
-from eth_defi.utils import ZERO_ADDRESS_STR
-
 # How big are our ABI and contract caches
 _CACHE_SIZE = 512
 
 
+#: Ethereum 0x0000000000000000000000000000000000000000 address as a string.
+#:
+#: Legacy. Use one below.
+#:
+ZERO_ADDRESS_STR = "0x0000000000000000000000000000000000000000"
+
+#: Ethereum 0x0000000000000000000000000000000000000000 address
+ZERO_ADDRESS = ZERO_ADDRESS_STR
+
+
 @lru_cache(maxsize=_CACHE_SIZE)
 def get_abi_by_filename(fname: str) -> dict:
     """Reads a embedded ABI file and returns it.
@@ -288,6 +296,34 @@ def encode_function_args(func: ContractFunction, args: Sequence) -> bytes:
     return encoded_args
 
 
+def decode_function_output(func: ContractFunction, data: bytes) -> Any:
+    """Decode raw return value of Solidity function using Contract proxy object.
+
+    Uses `web3.Contract.functions` prepared function as the ABI source.
+
+    :param func:
+        Function which arguments we are going to encode.
+
+        Must be bound.
+
+    :param result:
+        Raw encoded Solidity bytes.
+    """
+    assert isinstance(func, ContractFunction)
+
+    web3 = func.w3
+
+    fn_abi, fn_selector, aligned_fn_arguments = get_function_info(
+        func.fn_name,
+        web3.codec,
+        func.contract_abi,
+        args=func.args,
+    )
+    arg_types = [t["type"] for t in fn_abi["outputs"]]
+    decoded_out = eth_abi.decode(arg_types, data)
+    return decoded_out
+
+
 def encode_function_call(
     func: ContractFunction,
     args: Sequence,
@@ -320,7 +356,10 @@ def encode_function_call(
         fn_abi,
         args,
     )
-    encoded = encode_abi(w3, fn_abi, fn_arguments, fn_selector)
+    try:
+        encoded = encode_abi(w3, fn_abi, fn_arguments, fn_selector)
+    except Exception as e:
+        raise RuntimeError(f"Could not encode ABI: {fn_abi}, args: {fn_arguments}") from e
     return HexBytes(encoded)
 
 
@@ -464,3 +503,4 @@ def get_function_selector(func: ContractFunction) -> bytes:
     function_signature = _abi_to_signature(fn_abi)
     fn_selector = function_signature_to_4byte_selector(function_signature)  # type: ignore
     return fn_selector
+