debug_traceBlock - Polygon RPC Method

async function profileBlockGas(provider, blockRlp) {
  const traces = await provider.send('debug_traceBlock', [
    blockRlp,
    { tracer: 'callTracer' }
  ]);

  let totalGas = 0;
  const txGas = [];

  for (const trace of traces) {
    const gasUsed = parseInt(trace.result.gasUsed, 16);
    totalGas += gasUsed;
    txGas.push({
      txHash: trace.txHash,
      gasUsed,
      type: trace.result.type,
      hasSubCalls: (trace.result.calls || []).length > 0
    });
  }

  // Sort by gas usage
  txGas.sort((a, b) => b.gasUsed - a.gasUsed);

  console.log(`Block total gas: ${totalGas}`);
  console.log('Top gas consumers:');
  for (const tx of txGas.slice(0, 5)) {
    const pct = ((tx.gasUsed / totalGas) * 100).toFixed(1);
    console.log(`  ${tx.txHash}: ${tx.gasUsed} gas (${pct}%)`);
  }

  return { totalGas, txGas };
}

async function detectMEVPatterns(provider, blockRlp) {
  const traces = await provider.send('debug_traceBlock', [
    blockRlp,
    { tracer: 'callTracer' }
  ]);

  const dexInteractions = [];

  for (let i = 0; i < traces.length; i++) {
    const trace = traces[i];
    const calls = flattenCalls(trace.result);

    for (const call of calls) {
      // Detect swap-like function selectors (e.g., Uniswap swapExactTokensForTokens)
      if (call.input && call.input.startsWith('0x38ed1739')) {
        dexInteractions.push({
          index: i,
          txHash: trace.txHash,
          to: call.to,
          type: 'swap'
        });
      }
    }
  }

  // Check for sandwich patterns (swap-X-swap by same sender)
  for (let i = 0; i < dexInteractions.length - 2; i++) {
    const first = dexInteractions[i];
    const last = dexInteractions[i + 2];
    if (first.txHash !== last.txHash &&
        traces[first.index].result.from === traces[last.index].result.from) {
      console.log(`Potential sandwich: tx ${first.index} and ${last.index}`);
    }
  }

  return dexInteractions;
}

function flattenCalls(trace) {
  const calls = [trace];
  for (const sub of trace.calls || []) {
    calls.push(...flattenCalls(sub));
  }
  return calls;
}

import requests

def trace_on_endpoint(endpoint, block_rlp):
    response = requests.post(endpoint, json={
        'jsonrpc': '2.0',
        'method': 'debug_traceBlock',
        'params': [block_rlp, {'tracer': 'callTracer'}],
        'id': 1
    })
    return response.json()['result']

# Compare traces from two different endpoints
block_rlp = '0xf90217a0...'
traces_a = trace_on_endpoint('https://api-polygon-mainnet-full.n.dwellir.com/YOUR_API_KEY', block_rlp)
traces_b = trace_on_endpoint('https://other-endpoint.example.com', block_rlp)

# Verify same number of traces
assert len(traces_a) == len(traces_b), 'Transaction count mismatch'

# Compare gas usage per transaction
for i, (a, b) in enumerate(zip(traces_a, traces_b)):
    gas_a = int(a['result']['gasUsed'], 16)
    gas_b = int(b['result']['gasUsed'], 16)
    if gas_a != gas_b:
        print(f'Gas mismatch at tx {i}: {gas_a} vs {gas_b}')
    else:
        print(f'Tx {i}: {gas_a} gas (consistent)')

async function safeTraceBlock(provider, blockRlp, options = {}) {
  const defaultOptions = {
    tracer: 'callTracer',
    timeout: '60s',
    ...options
  };

  try {
    return await provider.send('debug_traceBlock', [blockRlp, defaultOptions]);
  } catch (error) {
    if (error.code === -32601) {
      throw new Error('debug_traceBlock not available — ensure archive node with debug API');
    }
    if (error.message?.includes('timeout')) {
      console.warn('Trace timed out — retrying with reduced detail');
      return await provider.send('debug_traceBlock', [
        blockRlp,
        { ...defaultOptions, disableStorage: true, disableStack: true }
      ]);
    }
    throw error;
  }
}