From 39998dcbb2a610d0325eadf01cee0b6396e681c9 Mon Sep 17 00:00:00 2001
From: nickwinder <nfxdevelopment@gmail.com>
Date: Wed, 13 May 2026 11:43:04 +1200
Subject: [PATCH] fix(eval): swallow microsandbox 'egress frame too large' so
 the eval doesn't die mid-run
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microsandbox's egressIntercept() runs its event-pump loop as a fire-and-forget
async IIFE with try/finally — no catch. When the native binding throws
"egress frame too large" (the protocol parser hit a frame above its internal
buffer), the rejection escapes as unhandledRejection and crashes the parent
node process, taking out the whole eval. We've reproduced this consistently
on TC-005 with the Nutrient Web SDK suite — TC-001 finishes, then the next
test's executor sandbox triggers the bug and the entire eval dies before any
judging happens.

Install a process-level unhandledRejection handler at the CLI entry point
that ONLY catches errors with code === 'GenericFailure' AND message matching
/egress frame too large/. Re-throw everything else so genuine unhandled
rejections still crash loudly. Egress logging for that one test case stops
(it's observability, not correctness — the eval can still execute, snapshot,
and judge).

After this fix the same TC-001+TC-005 run completes and both produce judge
results.
---
 src/index.ts | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/src/index.ts b/src/index.ts
index 5d8ef74..90f93a2 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -1,5 +1,23 @@
 #!/usr/bin/env node
 
+// microsandbox's egress-intercept background loop runs as a fire-and-forget IIFE
+// inside its egressIntercept() helper, with try/finally but no catch. When the
+// native binding throws (most commonly "egress frame too large" — a frame from
+// the sandbox exceeds the protocol parser's buffer), it becomes an
+// unhandledRejection and crashes the parent process mid-run, taking out the
+// whole eval. Swallow that specific error so the eval keeps making forward
+// progress; egress logging for that test case stops, which is acceptable
+// (egress logs are observability, not correctness). Re-throw everything else.
+process.on('unhandledRejection', (err) => {
+  const e = err as { message?: string; code?: string } | null | undefined;
+  const msg = e?.message ?? '';
+  if (e?.code === 'GenericFailure' && /egress frame too large/i.test(msg)) {
+    console.warn(`\n[egress] interception loop terminated mid-run: ${msg} — eval continuing without further egress logging for this case`);
+    return;
+  }
+  throw err as Error;
+});
+
 import { Command } from 'commander';
 import chalk from 'chalk';
 import { readFileSync } from 'node:fs';