fix(scripting): flush Node output before exit

package.json

@@ -7,6 +7,7 @@
   "main": "./src/plugin.ts",
   "scripts": {
     "build": "node build.mjs",
+    "test": "node --test tests/*.test.mjs",
     "release": "node build.mjs && node generate-manifest.mjs"
   },
   "peerDependencies": {

src/lib/scriptEngine.ts

@@ -165,6 +165,11 @@ export const nodeHostWrapperSource = `
 'use strict';
 var Worker = require('worker_threads').Worker;
 var _chunks = [];
+function _writeResult(result, exitCode) {
+  process.stdout.write(JSON.stringify(result) + '\\n', function() {
+    process.exit(exitCode);
+  });
+}
 process.stdin.on('data', function(c) { _chunks.push(c); });
 process.stdin.on('end', function() {
   var _input = JSON.parse(Buffer.concat(_chunks).toString('utf-8'));
@@ -183,23 +188,20 @@ process.stdin.on('end', function() {
 
   var _timeout = setTimeout(function() {
     _worker.terminate();
-    process.stdout.write(JSON.stringify({ success: false, logs: [], error: 'Script execution timed out after 10000ms', cancelled: false, modifiedVariables: {} }) + '\\n');
-    process.exit(1);
+    _writeResult({ success: false, logs: [], error: 'Script execution timed out after 10000ms', cancelled: false, modifiedVariables: {} }, 1);
   }, 10000);
 
   _worker.on('message', function(msg) {
     if (msg.type === 'done') {
       clearTimeout(_timeout);
-      process.stdout.write(JSON.stringify({ success: msg.success, logs: msg.logs || [], assertions: msg.assertions || [], cancelled: msg.cancelled || false, error: msg.error, modifiedRequest: msg.modifiedRequest, modifiedResponse: msg.modifiedResponse, modifiedVariables: msg.modifiedVariables || {} }) + '\\n');
       _worker.terminate();
-      process.exit(msg.success ? 0 : 1);
+      _writeResult({ success: msg.success, logs: msg.logs || [], assertions: msg.assertions || [], cancelled: msg.cancelled || false, error: msg.error, modifiedRequest: msg.modifiedRequest, modifiedResponse: msg.modifiedResponse, modifiedVariables: msg.modifiedVariables || {} }, msg.success ? 0 : 1);
     }
   });
 
   _worker.on('error', function(err) {
     clearTimeout(_timeout);
-    process.stdout.write(JSON.stringify({ success: false, logs: [], error: err.stack || err.message || String(err), cancelled: false, modifiedVariables: {} }) + '\\n');
-    process.exit(1);
+    _writeResult({ success: false, logs: [], error: err.stack || err.message || String(err), cancelled: false, modifiedVariables: {} }, 1);
   });
 
   _worker.postMessage({ type: 'start', script: _input.scriptBody, request: _input.request || {}, response: _input.response || null, envData: _envData, variablesData: _variablesData });

tests/node-host-wrapper.test.mjs

@@ -0,0 +1,72 @@
+import assert from "node:assert/strict";
+import { spawn } from "node:child_process";
+import { readFile } from "node:fs/promises";
+import test from "node:test";
+
+import { transform } from "esbuild";
+
+async function loadScriptEngineSources() {
+  const source = await readFile(new URL("../src/lib/scriptEngine.ts", import.meta.url), "utf8");
+  const { code } = await transform(source, {
+    format: "esm",
+    loader: "ts",
+    target: "node20",
+  });
+  const moduleUrl = `data:text/javascript;base64,${Buffer.from(code).toString("base64")}`;
+  return import(moduleUrl);
+}
+
+function runNodeWrapper(nodeHostWrapperSource, payload) {
+  return new Promise((resolve, reject) => {
+    const child = spawn(process.execPath, ["-e", nodeHostWrapperSource], {
+      stdio: ["pipe", "pipe", "pipe"],
+    });
+    let stdout = "";
+    let stderr = "";
+
+    child.stdout.on("data", (chunk) => {
+      stdout += chunk;
+    });
+    child.stderr.on("data", (chunk) => {
+      stderr += chunk;
+    });
+    child.on("error", reject);
+    child.on("close", (code) => resolve({ code, stdout, stderr }));
+    child.stdin.end(JSON.stringify(payload));
+  });
+}
+
+test("node worker flushes large JSON results before exiting", async () => {
+  const { nodeHostWrapperSource, workerSource } = await loadScriptEngineSources();
+  const body = "A".repeat(4 * 1024 * 1024);
+  const result = await runNodeWrapper(nodeHostWrapperSource, {
+    workerSource,
+    scriptBody: "voiden.request.body = voiden.request.body;",
+    request: { body },
+    response: null,
+    envVars: {},
+    variables: {},
+  });
+
+  assert.equal(result.code, 0, result.stderr);
+  const parsed = JSON.parse(result.stdout.trim());
+  assert.equal(parsed.success, true);
+  assert.equal(parsed.modifiedRequest.body, body);
+});
+
+test("node worker preserves the failure exit code after flushing", async () => {
+  const { nodeHostWrapperSource, workerSource } = await loadScriptEngineSources();
+  const result = await runNodeWrapper(nodeHostWrapperSource, {
+    workerSource,
+    scriptBody: 'throw new Error("boom");',
+    request: {},
+    response: null,
+    envVars: {},
+    variables: {},
+  });
+
+  assert.equal(result.code, 1);
+  const parsed = JSON.parse(result.stdout.trim());
+  assert.equal(parsed.success, false);
+  assert.match(parsed.error, /boom/);
+});