feat: add event filter creation and log fetching to ContractEvent

[Copilot]

ContractEvent had no way to build eth_getLogs filter parameters or fetch/decode logs from the chain, making event-driven workflows awkward.

Changes

• ContractEvent.build_filter() — returns a ready-to-use FilterParams dict by delegating to web3.py's construct_event_filter_params. Supports address, argument_filters (indexed param filtering encoded as topics), from_block, and to_block.
• ContractEvent.get_logs() — async method that calls eth_getLogs with the built filter and returns a decoded list[EventData] via the existing parse_log().

Usage

transfer = ERC20.events.Transfer

# Build a filter (e.g. to pass to w3.eth.get_logs manually)
params = transfer.build_filter(
    address=token_addr,
    argument_filters={"from": owner},
    from_block=deploy_block,
)

# Or fetch + decode in one call
logs = await transfer.get_logs(
    w3,
    address=token_addr,
    argument_filters={"from": owner},
    from_block=deploy_block,
)
for log in logs:
    print(log["args"]["from"], log["args"]["to"], log["args"]["amount"])

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Problem: event filter creation is not well supported</issue_title>
<issue_description>find a elegant way to support events use cases:

• filter creation
• logs/data encoding/decoding</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes Problem: event filter creation is not well supported #29

---

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[Copilot]

Pull request overview

Adds first-class event log querying support to ContractEvent, enabling consumers of eth_contract to build eth_getLogs filter parameters and fetch/decode logs directly via the existing event decoding flow.

Changes:

• Add ContractEvent.build_filter() to generate FilterParams via construct_event_filter_params.
• Add async ContractEvent.get_logs() to fetch logs with w3.eth.get_logs() and decode via parse_log().
• Add unit/integration tests covering filter construction and end-to-end log fetching/decoding; remove the corresponding README TODO item.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 2 comments.

File	Description
eth_contract/contract.py	Implements ContractEvent.build_filter() and ContractEvent.get_logs() and adds required imports.
tests/test_abi.py	Adds unit tests validating filter param construction (topics/address/block range/indexed arg filtering).
tests/test_erc20.py	Adds async integration test that deploys a mock ERC20, emits Transfer logs, and verifies get_logs() decoding/filtering.
README.md	Removes TODO entry now addressed by this PR.

[Copilot]

ChecksumAddress is imported twice (from eth_typing and again from web3.types), which redefines the name and will trip flake8/pyflakes (and also changes which type is referenced elsewhere in this module). Remove the web3.types.ChecksumAddress import or alias one of them to avoid the collision.

Suggested change

ChecksumAddress,

[Copilot]

The nested list-comprehension pattern (for decoded in [self.parse_log(log)]) makes the control flow harder to read/maintain. Consider using an explicit loop (or filter(None, ...)) to decode logs and skip None results more clearly.

Suggested change

	return [
	decoded
	for log in logs
	for decoded in [self.parse_log(log)]
	if decoded is not None
	]
	results: list[EventData] = []
	for log in logs:
	decoded = self.parse_log(log)
	if decoded is not None:
	results.append(decoded)
	return results

[yihuang]

Fix ci failure

[Copilot]

Fix ci failure

Fixed in 643d2cc — removed the duplicate ChecksumAddress import from web3.types (keeping the one from eth_typing that was already present), and simplified the get_logs return to use an explicit loop as suggested.