Hermes-agent

apps/desktop/scripts/leak-typing.mjs

@@ -0,0 +1,222 @@
+#!/usr/bin/env node
+// Leak-detection harness — measure detached DOM, listener count, and FiberNode
+// growth as a function of keystrokes typed.
+//
+// Workflow:
+//   1. Open session, focus composer
+//   2. forceGC; capture baseline counts
+//   3. Repeat N rounds: type M chars, forceGC, capture counts, clear composer
+//   4. Print growth-per-round table
+//
+// Usage:
+//   node apps/desktop/scripts/leak-typing.mjs [--rounds=6] [--chars=200] [--cps=40] [--port=9222]
+
+import { writeFileSync } from 'node:fs'
+
+const args = Object.fromEntries(
+  process.argv.slice(2).flatMap(s => {
+    const m = s.match(/^--([^=]+)(?:=(.*))?$/)
+    return m ? [[m[1], m[2] ?? true]] : []
+  })
+)
+const PORT = Number(args.port ?? 9222)
+const ROUNDS = Number(args.rounds ?? 6)
+const CHARS = Number(args.chars ?? 200)
+const CPS = Number(args.cps ?? 40)
+
+const log = (...m) => console.log('[leak]', ...m)
+
+async function pickRenderer() {
+  const list = await (await fetch(`http://127.0.0.1:${PORT}/json/list`)).json()
+  return list.find(t => t.type === 'page' && t.url.startsWith('http'))
+}
+
+function connect(url) {
+  return new Promise((resolve, reject) => {
+    const ws = new WebSocket(url)
+    let id = 0
+    const pending = new Map()
+    const events = new Map()
+    ws.addEventListener('open', () =>
+      resolve({
+        send(method, params = {}) {
+          const myId = ++id
+          ws.send(JSON.stringify({ id: myId, method, params }))
+          return new Promise((res, rej) => pending.set(myId, { res, rej }))
+        },
+        on(method, h) {
+          if (!events.has(method)) events.set(method, [])
+          events.get(method).push(h)
+        },
+        close: () => ws.close()
+      })
+    )
+    ws.addEventListener('error', reject)
+    ws.addEventListener('message', ev => {
+      const m = JSON.parse(typeof ev.data === 'string' ? ev.data : ev.data.toString('utf8'))
+      if (m.id != null) {
+        const p = pending.get(m.id)
+        if (!p) return
+        pending.delete(m.id)
+        m.error ? p.rej(new Error(m.error.message)) : p.res(m.result)
+      } else if (m.method) {
+        ;(events.get(m.method) ?? []).forEach(h => h(m.params))
+      }
+    })
+  })
+}
+
+async function evalInPage(cdp, expr) {
+  const r = await cdp.send('Runtime.evaluate', { expression: expr, returnByValue: true })
+  if (r.exceptionDetails) throw new Error(r.exceptionDetails.text)
+  return r.result.value
+}
+
+async function forceGCAndSettle(cdp) {
+  for (let i = 0; i < 3; i++) {
+    await cdp.send('HeapProfiler.collectGarbage')
+    await new Promise(r => setTimeout(r, 60))
+  }
+}
+
+async function focusComposer(cdp) {
+  return await evalInPage(
+    cdp,
+    `(() => {
+      const el = document.querySelector('[data-slot="composer-rich-input"]')
+      if (!el) return false
+      el.focus()
+      const range = document.createRange()
+      range.selectNodeContents(el)
+      range.collapse(false)
+      const sel = window.getSelection()
+      sel.removeAllRanges()
+      sel.addRange(range)
+      return true
+    })()`
+  )
+}
+
+async function clearComposer(cdp) {
+  await evalInPage(
+    cdp,
+    `(() => {
+      const el = document.querySelector('[data-slot="composer-rich-input"]')
+      if (!el) return false
+      // Clear via the same path as the composer's clear flow:
+      // dispatch a single Backspace until empty would be N round-trips; quicker
+      // to directly assign empty text and fire input.
+      el.innerHTML = ''
+      el.dispatchEvent(new InputEvent('input', { bubbles: true, inputType: 'deleteContentBackward' }))
+      el.focus()
+      return el.innerText.length === 0
+    })()`
+  )
+}
+
+async function snapshotCounts(cdp) {
+  // Counts via Runtime.evaluate using internal V8 counters where possible.
+  // For DOM stats we directly query the document.
+  // Performance metrics include JSHeapUsedSize, Nodes, JSEventListeners, etc.
+  const { metrics } = await cdp.send('Performance.getMetrics')
+  const byName = Object.fromEntries(metrics.map(m => [m.name, m.value]))
+  // Total nodes in document
+  const docNodes = await evalInPage(
+    cdp,
+    `document.getElementsByTagName('*').length + document.querySelectorAll('*').length / 2`
+  )
+  return {
+    heapUsedMB: (byName.JSHeapUsedSize / 1024 / 1024) || 0,
+    heapTotalMB: (byName.JSHeapTotalSize / 1024 / 1024) || 0,
+    nodes: byName.Nodes || 0,
+    jsListeners: byName.JSEventListeners || 0,
+    docNodes,
+    layoutCount: byName.LayoutCount || 0,
+    recalcStyleCount: byName.RecalcStyleCount || 0,
+    fps: byName.FramesPerSecond || 0
+  }
+}
+
+async function typeChars(cdp, text, cps) {
+  const intervalMs = Math.max(1, Math.round(1000 / cps))
+  const start = Date.now()
+  for (let i = 0; i < text.length; i++) {
+    await cdp.send('Input.dispatchKeyEvent', { type: 'char', text: text[i], unmodifiedText: text[i] })
+    const expected = start + (i + 1) * intervalMs
+    const wait = expected - Date.now()
+    if (wait > 0) await new Promise(r => setTimeout(r, wait))
+  }
+}
+
+const lorem =
+  'the quick brown fox jumps over the lazy dog while the agent thinks really hard about why typing into this composer feels like wading through molasses on a hot afternoon '
+function genText(n) {
+  let s = ''
+  while (s.length < n) s += lorem
+  return s.slice(0, n)
+}
+
+async function main() {
+  log(`port ${PORT} · ${ROUNDS} rounds × ${CHARS} chars @ ${CPS} cps`)
+  const tgt = await pickRenderer()
+  log(`target ${tgt.url}`)
+  const cdp = await connect(tgt.webSocketDebuggerUrl)
+  await cdp.send('Runtime.enable')
+  await cdp.send('Performance.enable')
+  await cdp.send('DOM.enable')
+
+  const focused = await focusComposer(cdp)
+  if (!focused) {
+    console.error('composer not focusable')
+    process.exit(2)
+  }
+
+  await forceGCAndSettle(cdp)
+  const baseline = await snapshotCounts(cdp)
+  log('baseline:', JSON.stringify(baseline))
+
+  const text = genText(CHARS)
+  const history = [{ round: 0, ...baseline, charsTyped: 0 }]
+
+  for (let r = 1; r <= ROUNDS; r++) {
+    await typeChars(cdp, text, CPS)
+    await new Promise(res => setTimeout(res, 200))
+    await clearComposer(cdp)
+    await forceGCAndSettle(cdp)
+    const snap = await snapshotCounts(cdp)
+    snap.charsTyped = r * CHARS
+    snap.round = r
+    history.push(snap)
+    log(
+      `round ${r}: heap=${snap.heapUsedMB.toFixed(1)}MB ` +
+        `nodes=${snap.nodes} listeners=${snap.jsListeners} ` +
+        `domNodes=${Math.round(snap.docNodes)} ` +
+        `layoutCount=${snap.layoutCount} ` +
+        `Δheap=+${(snap.heapUsedMB - baseline.heapUsedMB).toFixed(2)}MB ` +
+        `Δnodes=+${snap.nodes - baseline.nodes} ` +
+        `Δlisteners=+${snap.jsListeners - baseline.jsListeners}`
+    )
+  }
+
+  console.log('\n=== GROWTH PER ROUND (averaged over last 5 rounds) ===')
+  const tail = history.slice(-5)
+  const first = tail[0]
+  const last = tail[tail.length - 1]
+  const rounds = last.round - first.round
+  const cells = ['heapUsedMB', 'nodes', 'jsListeners', 'docNodes', 'layoutCount']
+  for (const c of cells) {
+    const delta = last[c] - first[c]
+    const per = delta / Math.max(1, rounds)
+    const perChar = delta / Math.max(1, rounds * CHARS)
+    console.log(`  ${c.padEnd(16)}  Δtotal=${delta.toFixed(2).padStart(10)}  /round=${per.toFixed(2).padStart(8)}  /char=${perChar.toFixed(4).padStart(8)}`)
+  }
+
+  writeFileSync('/tmp/hermes-leak-history.json', JSON.stringify(history, null, 2))
+  log('wrote /tmp/hermes-leak-history.json')
+  cdp.close()
+}
+
+main().catch(e => {
+  console.error('[leak] fatal:', e.stack ?? e.message)
+  process.exit(1)
+})