Allow miners to post direction specific rates#7
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A miner could claim a third-party tx to the user's dest address as their own fulfillment. Store miner_dest_address on the swap struct at initiation and validate tx_info.sender against it during dest-side verification.
Miners can now post separate rates for each swap direction (e.g., 340 TAO/BTC for BTC->TAO, 350 TAO/BTC for TAO->BTC) to capture tx fee asymmetry. Commitment format bumped to v3 with two rate fields. Backend unchanged — each swap still stores one rate, selected by direction at initiation time.
Replace TAO-centric assumptions with canonical chain ordering so any pair (including non-TAO pairs like BTC-ETH) works correctly. TAO is preferred as the rate denomination when present, otherwise alphabetical ordering is used as a deterministic fallback. - Add canonical_pair() to chains.py with TAO-preference ordering - Rename rate_reverse → counter_rate across all files - Change get_rate_for_direction(source_is_tao) to accept chain name - Rename rate.py params: source_is_tao → is_reverse, tao_decimals/asset_decimals → dest_decimals/source_decimals - Filter miners with rate=0 for the desired direction (CLI + validator) - Fix test_scale.py swap encoding (missing miner_source_address, miner_dest_address, rate) - Fix float comparison for rate display → use string comparison - Add 5 unit tests: canonical_pair, direction after normalization, direction-specific rate calc
- Allow counter_rate=0 (miner only supports one direction) - Auto-select destination chain when only one option remains - Add context to chain prompts (you receive/send on this chain) - Display "not supported" for disabled directions in status/summary - Add 2 unit tests for single-direction parsing and normalization
- Use "send X, get Y" format for rate confirmation and swap summary - Split miners table into explicit BTC→TAO / TAO→BTC columns - Show "—" for disabled directions (rate=0) in tables - Use "not supported" label for disabled directions in status
Verify that chains sorting after "tao" alphabetically (e.g. "thor") still get TAO as dest, not alphabetical ordering.
Verifies the full defense-in-depth: get_rate_for_direction returns 0 for disabled direction, validator guard catches it, and calculate_dest_amount produces 0 as a fallback (contract rejects InvalidAmount).
- Swap rates during normalization when positional args used in non-canonical order (e.g. alw miner post tao ... btc ... 340 360) - Fix display showing "get 0" in green when forward rate is disabled - Consistent — in view_rates for rate=0 (matches view_miners)
anderdc
approved these changes
Apr 7, 2026
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Summary
Miners post a single bilateral rate that applies to both swap directions. But tx fees are asymmetric across chains — sending BTC costs more than receiving it. A single rate forces miners to average out that cost, meaning users get a worse rate on the cheap direction.
This adds direction-specific rates so miners can price each direction honestly (e.g., 340 TAO/BTC for BTC->TAO, 350 TAO/BTC for TAO->BTC). The spread captures the tx fee differential.
Approach
Commitment format bumped to v3 with two rate fields. The correct rate is selected based on swap direction at initiation time. The entire backend (validator verification, miner fulfillment, smart contract, voting) is unchanged — each swap on-chain still stores one rate, it's just the right one for that direction now.
Test plan
Reviewer experience
Start the dev environment and explore these flows:
Post a pair with directional rates (as miner):