fix(browse): GSTACK_CHROMIUM_NO_SANDBOX opt-out for Ubuntu/AppArmor (#1562)

Ubuntu/AppArmor configurations often block unprivileged Chromium sandboxing
for headless agent sessions even for normal users — /qa hangs without
--no-sandbox. The kernel policy denies the unprivileged user namespaces
Chromium needs.

Adds GSTACK_CHROMIUM_NO_SANDBOX=1 as an explicit user override that forces
the sandbox off without changing the default for everyone else. Re-authored
from PR #1562 onto v1.42.2.0's shouldEnableChromiumSandbox() helper —
purely additive, preserves the headed-launch sandbox-on-by-default behavior
that v1.42.2.0 shipped to kill the --no-sandbox yellow infobar.

Three new regression tests cover:
  - linux + override=1 → false (the named use case)
  - darwin + override=1 → false (env wins on any platform)
  - override=0 → does NOT trigger (must be exactly "1")

Original diff by @techcenter68 via #1562.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

browse/src/browser-manager.ts

@@ -59,6 +59,13 @@ export function isCustomChromium(): boolean {
  */
 export function shouldEnableChromiumSandbox(): boolean {
   if (process.platform === 'win32') return false;
+  // Explicit user override for Ubuntu/AppArmor and similar environments where
+  // unprivileged Chromium sandboxing is blocked even for normal users (the
+  // sandbox needs unprivileged user namespaces that the host policy denies,
+  // so /qa hangs without --no-sandbox). Setting GSTACK_CHROMIUM_NO_SANDBOX=1
+  // forces the sandbox off without changing the default for everyone else.
+  // See #1562.
+  if (process.env.GSTACK_CHROMIUM_NO_SANDBOX === '1') return false;
   const isRoot = typeof process.getuid === 'function' && process.getuid() === 0;
   return !(process.env.CI || process.env.CONTAINER || isRoot);
 }

browse/test/browser-manager-unit.test.ts

@@ -29,17 +29,20 @@ describe('shouldEnableChromiumSandbox', () => {
   const origPlatform = process.platform;
   const origCI = process.env.CI;
   const origContainer = process.env.CONTAINER;
+  const origNoSandbox = process.env.GSTACK_CHROMIUM_NO_SANDBOX;
   const origGetuid = process.getuid;
 
   beforeEach(() => {
     delete process.env.CI;
     delete process.env.CONTAINER;
+    delete process.env.GSTACK_CHROMIUM_NO_SANDBOX;
   });
 
   afterEach(() => {
     Object.defineProperty(process, 'platform', { value: origPlatform });
     if (origCI === undefined) delete process.env.CI; else process.env.CI = origCI;
     if (origContainer === undefined) delete process.env.CONTAINER; else process.env.CONTAINER = origContainer;
+    if (origNoSandbox === undefined) delete process.env.GSTACK_CHROMIUM_NO_SANDBOX; else process.env.GSTACK_CHROMIUM_NO_SANDBOX = origNoSandbox;
     process.getuid = origGetuid;
   });
 
@@ -90,6 +93,31 @@ describe('shouldEnableChromiumSandbox', () => {
     const { shouldEnableChromiumSandbox } = await import('../src/browser-manager');
     expect(shouldEnableChromiumSandbox()).toBe(false);
   });
+
+  // #1562 — Ubuntu/AppArmor opt-in override
+  it('linux + GSTACK_CHROMIUM_NO_SANDBOX=1 → false (Ubuntu/AppArmor opt-out)', async () => {
+    setPlatform('linux');
+    process.env.GSTACK_CHROMIUM_NO_SANDBOX = '1';
+    process.getuid = (() => 1000) as typeof process.getuid;
+    const { shouldEnableChromiumSandbox } = await import('../src/browser-manager');
+    expect(shouldEnableChromiumSandbox()).toBe(false);
+  });
+
+  it('darwin + GSTACK_CHROMIUM_NO_SANDBOX=1 → false (env override wins on any platform)', async () => {
+    setPlatform('darwin');
+    process.env.GSTACK_CHROMIUM_NO_SANDBOX = '1';
+    process.getuid = (() => 501) as typeof process.getuid;
+    const { shouldEnableChromiumSandbox } = await import('../src/browser-manager');
+    expect(shouldEnableChromiumSandbox()).toBe(false);
+  });
+
+  it('GSTACK_CHROMIUM_NO_SANDBOX=0 → does NOT trigger override (must be exactly "1")', async () => {
+    setPlatform('linux');
+    process.env.GSTACK_CHROMIUM_NO_SANDBOX = '0';
+    process.getuid = (() => 1000) as typeof process.getuid;
+    const { shouldEnableChromiumSandbox } = await import('../src/browser-manager');
+    expect(shouldEnableChromiumSandbox()).toBe(true);
+  });
 });
 
 // ─── resolveDisconnectCause ──────────────────────────────────────