fix(sandbox): scan session output without recursion

Author: icecrasher321

apps/sim/lib/mothership/tools/handlers/workbench-confidentiality.live.test.ts

@@ -77,6 +77,7 @@ import {
   readSandboxResourceScope,
   withSandboxResourceScope,
 } from '@/lib/mothership/tools/sandbox-resources'
+import { buildMothershipSandboxSession } from '@/lib/mothership/tools/sandbox-session'
 import { chatSandboxSessionKey } from '@/lib/mothership/tools/sandbox-session-key'
 import { ResolvedSecretTraceRegistry } from '@/executor/utils/resolved-secret-trace-registry'
 import { buildFunctionExecuteBody, functionExecuteTool } from '@/tools/function/execute'
@@ -369,6 +370,31 @@ describe('persistent workbench output confidentiality', () => {
     expect(result.raw.output).toHaveProperty('result.length', 100_001)
     expect(result.projected.safe).toBe(true)
   })
+  it.each([
+    ['array', '[', ']'],
+    ['object', '{"nested":', '}'],
+  ])(
+    'classifies deeply nested %s output without exhausting the call stack',
+    async (_kind, open, close) => {
+      await inResourceScope(async () => {
+        const session = await buildMothershipSandboxSession({
+          ...scope,
+          sessionKey: chatSandboxSessionKey(chatId),
+        })
+        const credential = session.envs!.SIM_API_KEY
+        const nested = (leaf: string) =>
+          JSON.parse(open.repeat(12_000) + JSON.stringify(leaf) + close.repeat(12_000))
+        expect(session.outputProvenance!(nested('ordinary output'))).toEqual({
+          status: 'exact',
+          entries: [],
+        })
+        expect(session.outputProvenance!(nested(credential))).toMatchObject({
+          status: 'exact',
+          entries: [{ name: 'SIM_API_KEY' }],
+        })
+      })
+    }
+  )
   it('revokes callback authentication before a result reaches the model', async () => {
     const result = await run(
       'printf "%s" "$SIM_API_KEY" > session-key.txt; printf "%s" "$SIM_ENDPOINT" > session-endpoint.txt; printf done'

apps/sim/lib/mothership/tools/sandbox-session.ts

@@ -27,16 +27,30 @@ import {
 
 const logger = createLogger('MothershipSandboxSession')
 
-/** Scans parsed sandbox JSON in place, including keys, without allocating a second payload. */
+/** Scans parsed sandbox JSON without copying the payload or consuming the call stack. */
 function containsSessionCredential(value: unknown, matcher: ResolvedSecretMatcher): boolean {
-  if (typeof value === 'string') return containsResolvedSecret(value, matcher)
-  if (value === null || typeof value !== 'object') return false
-  if (Array.isArray(value)) return value.some((item) => containsSessionCredential(item, matcher))
-  const record = toRecord(value)
-  for (const key in record) {
-    if (!Object.hasOwn(record, key)) continue
-    if (containsResolvedSecret(key, matcher) || containsSessionCredential(record[key], matcher)) {
-      return true
+  function* fields(record: Record<string, unknown>): Generator<unknown> {
+    for (const key in record) {
+      if (!Object.hasOwn(record, key)) continue
+      yield key
+      yield record[key]
+    }
+  }
+
+  const pending: Iterator<unknown>[] = [[value].values()]
+  while (pending.length > 0) {
+    const next = pending[pending.length - 1].next()
+    if (next.done) {
+      pending.pop()
+      continue
+    }
+    const current = next.value
+    if (typeof current === 'string') {
+      if (containsResolvedSecret(current, matcher)) return true
+    } else if (Array.isArray(current)) {
+      pending.push(current.values())
+    } else if (current !== null && typeof current === 'object') {
+      pending.push(fields(toRecord(current)))
     }
   }
   return false