From 3e93ba85da5814884185b88f98e414e1a4ecd191 Mon Sep 17 00:00:00 2001
From: Oscar-Williams <319719771+Oscar-Williams@users.noreply.github.com>
Date: Wed, 23 Sep 2026 23:38:40 +0800
Subject: [PATCH 1/2] fix(npm): hide native CLI consoles on Windows

Pass windowsHide to both native launcher paths so GUI-hosted harnesses do not flash a console on each invocation. Add Node test coverage for the default and explicit override behavior.
---
 npm/cli/lib/child.js               |  2 +-
 npm/cli/lib/update.js              |  4 +--
 npm/cli/package.json               |  2 +-
 npm/cli/test/windows-hide.test.mjs | 53 ++++++++++++++++++++++++++++++
 4 files changed, 57 insertions(+), 4 deletions(-)
 create mode 100644 npm/cli/test/windows-hide.test.mjs

diff --git a/npm/cli/lib/child.js b/npm/cli/lib/child.js
index c0c0f5711..30e717b9a 100644
--- a/npm/cli/lib/child.js
+++ b/npm/cli/lib/child.js
@@ -1,7 +1,7 @@
 import { spawn } from "node:child_process";
 
 export async function runChild(command, args, options = {}) {
-  const child = spawn(command, args, { stdio: "inherit", ...options });
+  const child = spawn(command, args, { stdio: "inherit", windowsHide: true, ...options });
   const forward = (signal) => {
     if (!child.killed) {
       try {
diff --git a/npm/cli/lib/update.js b/npm/cli/lib/update.js
index 076a2a8ae..1a0a0fa74 100644
--- a/npm/cli/lib/update.js
+++ b/npm/cli/lib/update.js
@@ -57,10 +57,10 @@ export async function updateNpmInstall({
   return { code: 0, signal: null };
 }
 
-function productionRunner() {
+export function productionRunner() {
   return {
     output(command, args) {
-      const result = spawnSync(command, args, { encoding: "utf8" });
+      const result = spawnSync(command, args, { encoding: "utf8", windowsHide: true });
       if (result.error) {
         throw result.error;
       }
diff --git a/npm/cli/package.json b/npm/cli/package.json
index 07a239118..32d37f73d 100644
--- a/npm/cli/package.json
+++ b/npm/cli/package.json
@@ -15,7 +15,7 @@
     "LICENSE"
   ],
   "scripts": {
-    "test": "node --test test/*.test.mjs"
+    "test": "node --experimental-test-module-mocks --test test/*.test.mjs"
   },
   "engines": {
     "node": ">=22"
diff --git a/npm/cli/test/windows-hide.test.mjs b/npm/cli/test/windows-hide.test.mjs
new file mode 100644
index 000000000..157520704
--- /dev/null
+++ b/npm/cli/test/windows-hide.test.mjs
@@ -0,0 +1,53 @@
+import assert from "node:assert/strict";
+import { EventEmitter } from "node:events";
+import { mock, test } from "node:test";
+
+test("npm launcher hides native child consoles by default", async (t) => {
+  const spawnCalls = [];
+  const syncCalls = [];
+  mock.module("node:child_process", {
+    exports: {
+      spawn: (...args) => {
+        spawnCalls.push(args);
+        const child = new EventEmitter();
+        queueMicrotask(() => child.emit("exit", 0, null));
+        return child;
+      },
+      spawnSync: (...args) => {
+        syncCalls.push(args);
+        return { status: 0, stdout: "output", stderr: "" };
+      },
+    },
+  });
+  t.after(() => mock.restoreAll());
+
+  const { runChild } = await import("../lib/child.js?windows-hide-child");
+  const { productionRunner } = await import("../lib/update.js?windows-hide-update");
+
+  await runChild("mnemon", ["status"]);
+  const runner = productionRunner();
+  assert.equal(runner.output("npm", ["--version"]), "output");
+
+  assert.equal(spawnCalls[0][2].windowsHide, true);
+  assert.equal(syncCalls[0][2].windowsHide, true);
+});
+
+test("explicit child options can still override the default", async () => {
+  const spawnCalls = [];
+  mock.module("node:child_process", {
+    exports: {
+      spawn: (...args) => {
+        spawnCalls.push(args);
+        const child = new EventEmitter();
+        queueMicrotask(() => child.emit("exit", 0, null));
+        return child;
+      },
+      spawnSync: () => ({ status: 0, stdout: "", stderr: "" }),
+    },
+  });
+
+  const { runChild } = await import("../lib/child.js?windows-hide-override");
+  await runChild("mnemon", ["status"], { windowsHide: false });
+  assert.equal(spawnCalls[0][2].windowsHide, false);
+  mock.restoreAll();
+});

From 49d999247542b2130e452046f903261095ef926c Mon Sep 17 00:00:00 2001
From: Oscar-Williams <319719771+Oscar-Williams@users.noreply.github.com>
Date: Thu, 24 Sep 2026 15:50:03 +0800
Subject: [PATCH 2/2] test: use Node 22 module mock option

---
 npm/cli/test/windows-hide.test.mjs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/npm/cli/test/windows-hide.test.mjs b/npm/cli/test/windows-hide.test.mjs
index 157520704..e5e867f4a 100644
--- a/npm/cli/test/windows-hide.test.mjs
+++ b/npm/cli/test/windows-hide.test.mjs
@@ -6,7 +6,7 @@ test("npm launcher hides native child consoles by default", async (t) => {
   const spawnCalls = [];
   const syncCalls = [];
   mock.module("node:child_process", {
-    exports: {
+    namedExports: {
       spawn: (...args) => {
         spawnCalls.push(args);
         const child = new EventEmitter();
@@ -35,7 +35,7 @@ test("npm launcher hides native child consoles by default", async (t) => {
 test("explicit child options can still override the default", async () => {
   const spawnCalls = [];
   mock.module("node:child_process", {
-    exports: {
+    namedExports: {
       spawn: (...args) => {
         spawnCalls.push(args);
         const child = new EventEmitter();