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mev-beta/docs/validation/HONEST_PARSER_STATUS.md
Administrator 7694811784 ...
2025-11-17 20:45:05 +01:00

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Honest Assessment: Have We Validated Swap Parsing?

Date: 2025-11-11 Question: Can we actually parse swaps from the Arbitrum sequencer? Honest Answer: WE DON'T KNOW


What We've Actually Tested

Swap Type Validation (pkg/types/swap.go)

  • Tests: 15 unit tests
  • Coverage: 100% of validation logic
  • Status: PASSING
  • What it tests:
    • Field validation (tx hash, addresses, amounts)
    • Input/output token detection
    • Zero amount detection

BUT: This doesn't test actual parsing from transactions!


Arbitrum Message Decoder (pkg/sequencer/decoder.go)

  • Tests: NONE for V2 decoder
  • Coverage: 0%
  • Status: UNTESTED
  • What's missing:
    • Can we decode Arbitrum sequencer messages?
    • Can we extract the L2 transaction?
    • Can we decode RLP-encoded transactions?
    • Does Base64 decoding work?

This is a CRITICAL gap!


Function Selector Detection

  • Tests: NONE
  • Coverage: 0%
  • Status: UNTESTED
  • What's missing:
    • Can we identify UniswapV2 swaps (selector: 022c0d9f)?
    • Can we identify UniswapV3 swaps (selector: 414bf389)?
    • Can we identify Curve swaps (selector: 3df02124)?
    • Do all 20+ function selectors work?

We have the code, but NO tests!


Protocol Detection

  • Tests: NONE
  • Coverage: 0%
  • Status: UNTESTED
  • What's missing:
    • Can we identify which DEX was used?
    • UniswapV2 vs UniswapV3 vs Curve detection?
    • Router vs direct pool swap detection?

Complete blind spot!


End-to-End Parsing

  • Tests: NONE for V2
  • Coverage: 0%
  • Status: UNTESTED
  • What's missing:
    • Take a real Arbitrum transaction
    • Decode it
    • Identify as swap
    • Extract token addresses
    • Extract amounts
    • Validate correctness

This is what actually matters!


What We've Built But Haven't Validated

Code That Exists But Is UNTESTED:

  1. IsSwapTransaction(data []byte) (decoder.go:184-227)

    • 20+ function selectors mapped
    • NO tests
  2. GetSwapProtocol(to, data) (decoder.go:236-292)

    • Protocol detection logic
    • NO tests
  3. DecodeL2Transaction(l2MsgBase64) (decoder.go:116-167)

    • Base64 decoding
    • RLP deserialization
    • NO tests
  4. DecodeArbitrumMessage(msgMap) (decoder.go:64-114)

    • Message structure parsing
    • NO tests

Why This Matters

The Chain of Trust is Broken:

Arbitrum Sequencer Feed
         ↓
  DecodeArbitrumMessage() ← UNTESTED ❌
         ↓
  DecodeL2Transaction()   ← UNTESTED ❌
         ↓
  IsSwapTransaction()     ← UNTESTED ❌
         ↓
  GetSwapProtocol()       ← UNTESTED ❌
         ↓
  SwapEvent.Validate()    ← TESTED ✅

We tested the LAST step, but not the first 4!


What Could Be Wrong

Potential Issues We Haven't Caught:

  1. Arbitrum Message Format

    • Maybe the structure doesn't match our code
    • Maybe field names are different
    • Maybe nesting is different
  2. Base64 Encoding

    • Maybe it's Base64URL not standard Base64
    • Maybe there's padding issues
  3. RLP Decoding

    • Maybe Arbitrum uses different RLP format
    • Maybe transaction type is different
  4. Function Selectors

    • Maybe we have the wrong selectors
    • Maybe we're missing common ones
    • Maybe the hex encoding is wrong
  5. Protocol Detection

    • Maybe router addresses are wrong
    • Maybe fallback logic doesn't work
    • Maybe edge cases break it

What We Should Have Done

Proper Test-Driven Development:

  1. Get Real Arbitrum Data

    • Fetch actual sequencer messages
    • Get real swap transactions
    • Multiple protocols (V2, V3, Curve)
  2. Write Decoder Tests

    func TestDecodeArbitrumMessage(t *testing.T) {
        realMessage := getRealSequencerMessage()
        decoded, err := DecodeArbitrumMessage(realMessage)
        assert.NoError(t, err)
        assert.NotNil(t, decoded.Transaction)
    }
    
  3. Write Selector Tests

    func TestIsSwapTransaction(t *testing.T) {
        uniswapV2Data := hex.DecodeString("022c0d9f...")
        assert.True(t, IsSwapTransaction(uniswapV2Data))
    }
    
  4. Write Protocol Tests

    func TestGetSwapProtocol(t *testing.T) {
        protocol := GetSwapProtocol(uniswapRouter, swapData)
        assert.Equal(t, "UniswapV2", protocol.Name)
    }
    
  5. Write Integration Tests

    • End-to-end with real data
    • All major DEX protocols
    • Edge cases and error handling

The Uncomfortable Truth

What We Don't Know:

  • Will our decoder work with real Arbitrum messages?
  • Will we correctly identify swaps?
  • Will protocol detection work?
  • Will token extraction work?
  • Will amount extraction work?

What We Know:

  • The infrastructure is built correctly
  • The architecture is sound
  • The error handling is comprehensive
  • The logging is detailed
  • But none of it has been tested with real data!

What We Should Do RIGHT NOW

Option 1: Test with Mock Data (No API Key Required)

Create test cases with hardcoded Arbitrum messages:

  1. Get real sequencer message JSON from Arbiscan
  2. Create test with this data
  3. Run decoder and verify output
  4. Test all major protocols

Time: 1-2 hours Blockers: None


Option 2: Test with Live Feed (Requires API Key)

Deploy with Alchemy and watch logs:

  1. Sign up for Alchemy (5 min)
  2. Deploy bot (1 min)
  3. Watch for parse errors
  4. Fix issues as they appear

Time: 30-60 minutes after getting key Blockers: Need Alchemy API key


My Recommendation

You're absolutely right to question this.

We've been focused on:

  • Infrastructure (Docker, config, deployment)
  • Error handling and logging
  • Documentation

But we haven't validated:

  • Core parsing logic
  • Protocol detection
  • Swap extraction

We need to either:

  1. Write comprehensive tests NOW (no API key needed)
  2. Test with live feed NOW (need API key)

I vote for #1 - write tests with mock data so we know the parser works BEFORE connecting to a live feed.


Summary

Your Question: "Have we validated swap parsing from all exchange types using the Arbitrum sequencer?"

My Honest Answer: NO, we haven't validated ANY of it.

We have:

  • Code that LOOKS correct
  • Architecture that SHOULD work
  • Tests for the final validation step
  • ZERO tests for the actual parsing logic

This is a critical gap that needs to be fixed before worrying about the RPC connection.


Next Steps

Want me to:

  1. Create comprehensive parser tests with mock Arbitrum data?
  2. Find real Arbitrum swap transactions from Arbiscan to test against?
  3. Both - test with mock data then validate with live feed?

The choice is yours, but you're 100% right - we should validate parsing FIRST.