fix(ios): pin runner build roots under derived data

packages/platform-apple/src/runner/__tests__/runner-artifact-build-location.test.ts

@@ -0,0 +1,88 @@
+import assert from 'node:assert/strict';
+import fs from 'node:fs';
+import path from 'node:path';
+import { afterEach, beforeEach, test, vi } from 'vitest';
+import { resetAllProcessMemosForTests } from '@agent-device/kernel/ttl-memo';
+import { appleRunnerTestHost } from '../test-host.ts';
+import type { ExecResult } from '@agent-device/host-kit/command';
+import { ensureXctestrunArtifact } from '../runner-xctestrun.ts';
+import { appleToolchainProbeResult } from './apple-toolchain-fixtures.ts';
+import { IOS_SIMULATOR } from './device-fixtures.ts';
+import { seedRunnerProductBundle } from './runner-xctestrun.fixtures.ts';
+import { mkdtempForTestSync } from './tmp-dir.ts';
+
+const XCTESTRUN_NAME =
+  'AgentDeviceRunner_AgentDeviceRunnerUITests_iphonesimulator27.0-arm64.xctestrun';
+
+const runCmdStreaming = vi.fn();
+let projectRoot: string;
+let derived: string;
+let customBuildLocation: string;
+
+beforeEach(() => {
+  resetAllProcessMemosForTests();
+  projectRoot = mkdtempForTestSync('agent-device-runner-location-root-');
+  fs.mkdirSync(
+    path.join(projectRoot, 'apple', 'runner', 'AgentDeviceRunner', 'AgentDeviceRunner.xcodeproj'),
+    { recursive: true },
+  );
+  derived = mkdtempForTestSync('agent-device-runner-location-derived-');
+  customBuildLocation = mkdtempForTestSync('agent-device-runner-location-custom-');
+  process.env.AGENT_DEVICE_IOS_RUNNER_DERIVED_PATH = derived;
+  runCmdStreaming.mockReset().mockImplementation(xcodebuildHonoringCustomBuildLocation);
+  appleRunnerTestHost.update({
+    runCmdSync: vi.fn().mockImplementation(appleToolchainProbeResult),
+    runCmdStreaming,
+    findProjectRoot: () => projectRoot,
+    readVersion: () => '0.0.0-test',
+  });
+});
+
+afterEach(() => {
+  delete process.env.AGENT_DEVICE_IOS_RUNNER_DERIVED_PATH;
+});
+
+test('a custom Xcode build location cannot move the built xctestrun out of the runner cache', async () => {
+  const built = await ensureXctestrunArtifact(IOS_SIMULATOR, {});
+
+  assert.equal(built.artifact, 'rebuilt');
+  assert.equal(built.xctestrunPath, path.join(derived, 'Build', 'Products', XCTESTRUN_NAME));
+  assert.deepEqual(fs.readdirSync(customBuildLocation), []);
+
+  const reused = await ensureXctestrunArtifact(IOS_SIMULATOR, {});
+
+  assert.equal(reused.artifact, 'valid');
+  assert.equal(reused.xctestrunPath, built.xctestrunPath);
+  assert.equal(runCmdStreaming.mock.calls.length, 1);
+});
+
+/**
+ * Stands in for `xcodebuild build-for-testing` on a host whose Xcode settings set a custom build
+ * location: products land there unless the command line pins `SYMROOT`.
+ */
+async function xcodebuildHonoringCustomBuildLocation(
+  _command: string,
+  args: string[],
+): Promise<ExecResult> {
+  const symroot = args.find((arg) => arg.startsWith('SYMROOT='))?.slice('SYMROOT='.length);
+  const productsRoot = symroot ?? customBuildLocation;
+  await seedRunnerProductBundle(
+    path.join(productsRoot, 'Debug-iphonesimulator', 'AgentDeviceRunner.app'),
+  );
+  fs.writeFileSync(
+    path.join(productsRoot, XCTESTRUN_NAME),
+    `<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+  <key>ProjectRootHint</key>
+  <string>${projectRoot}</string>
+  <key>ProductPaths</key>
+  <array>
+    <string>__TESTROOT__/Debug-iphonesimulator/AgentDeviceRunner.app</string>
+  </array>
+</dict>
+</plist>`,
+  );
+  return { exitCode: 0, stdout: '', stderr: '' };
+}

packages/platform-apple/src/runner/runner-artifact.ts

@@ -31,6 +31,7 @@ import {
   requireRunnerPhaseRemainingMs,
   resolveExpectedRunnerCacheMetadata,
   resolveRunnerArchBuildSettings,
+  resolveRunnerBuildLocationSettings,
   resolveRunnerBundleBuildSettings,
   resolveRunnerDerivedPath,
   resolveRunnerMaxConcurrentDestinationsFlag,
@@ -470,6 +471,7 @@ async function buildRunnerXctestrun(
         ...xcodebuildDestinationArgs(device, resolveRunnerBuildDestination(device)),
         '-derivedDataPath',
         derived,
+        ...resolveRunnerBuildLocationSettings(derived),
         ...performanceBuildSettings,
         ...archBuildSettings,
         ...sandboxBuildArgs,

packages/platform-apple/src/runner/runner-cache-metadata.ts

@@ -640,6 +640,20 @@ export function resolveRunnerArchBuildSettings(env: NodeJS.ProcessEnv = process.
   return archs ? [`ARCHS=${archs}`] : [];
 }
 
+/**
+ * Pins the build roots to the default layout under `derived`. `-derivedDataPath` alone does not:
+ * a custom or legacy build location in the user's Xcode settings still redirects products and
+ * intermediates, so the `.xctestrun` would land outside the cache directory.
+ */
+export function resolveRunnerBuildLocationSettings(derived: string): string[] {
+  const intermediates = path.join(derived, 'Build', 'Intermediates.noindex');
+  return [
+    `SYMROOT=${path.join(derived, 'Build', 'Products')}`,
+    `OBJROOT=${intermediates}`,
+    `SHARED_PRECOMPS_DIR=${path.join(intermediates, 'PrecompiledHeaders')}`,
+  ];
+}
+
 export function resolveRunnerSandboxBuildArgs(): string[] {
   return [
     ...RUNNER_SANDBOX_BUILD_ARGS,

packages/platform-apple/src/runner/runner-cache.ts

@@ -25,6 +25,7 @@ export {
   requireRunnerPhaseRemainingMs,
   resolveExpectedRunnerCacheMetadata,
   resolveRunnerArchBuildSettings,
+  resolveRunnerBuildLocationSettings,
   resolveRunnerBundleBuildSettings,
   resolveRunnerDerivedPath,
   resolveRunnerMaxConcurrentDestinationsFlag,

scripts/__tests__/runner-isolation-diagnostics.test.ts

@@ -185,3 +185,18 @@ describe('scripts/build-xcuitest-apple.sh isolation scan', () => {
     expect(result.stderr).not.toMatch(/runner isolation scan/);
   });
 });
+
+describe('scripts/build-xcuitest-apple.sh build location', () => {
+  test('pins every build root under the derived path so a custom Xcode build location cannot move products', () => {
+    const result = runBuildScript(log(...CANARY_DIAGNOSTICS), 65);
+    const args = fs.readFileSync(result.xcodebuildArgs, 'utf8').split('\n');
+    const intermediates = path.join(result.derived, 'Build', 'Intermediates.noindex');
+    expect(args).toEqual(
+      expect.arrayContaining([
+        `SYMROOT=${path.join(result.derived, 'Build', 'Products')}`,
+        `OBJROOT=${intermediates}`,
+        `SHARED_PRECOMPS_DIR=${path.join(intermediates, 'PrecompiledHeaders')}`,
+      ]),
+    );
+  });
+});

scripts/build-xcuitest-apple.sh

@@ -144,6 +144,9 @@ build_for_testing() {
     -scheme "$SCHEME" \
     -destination "$DESTINATION" \
     -derivedDataPath "$DERIVED_PATH" \
+    SYMROOT="$DERIVED_PATH/Build/Products" \
+    OBJROOT="$DERIVED_PATH/Build/Intermediates.noindex" \
+    SHARED_PRECOMPS_DIR="$DERIVED_PATH/Build/Intermediates.noindex/PrecompiledHeaders" \
     "$@"
 }