xcodebuild hangs after BUILD SUCCEEDED on Xcode 26.2+ / macOS 26.3

[rckm]

Environment

System:
  OS: macOS 26.3
  CPU: (14) arm64 Apple M4 Pro
  Memory: 237.67 MB / 24.00 GB
  Shell:
    version: "5.9"
    path: /bin/zsh
Binaries:
  Node:
    version: 20.19.5
    path: /Users/rckm/.nvm/versions/node/v20.19.5/bin/node
  npm:
    version: 10.8.2
    path: /Users/rckm/.nvm/versions/node/v20.19.5/bin/npm
Managers:
  CocoaPods:
    version: 1.16.2
    path: /opt/homebrew/bin/pod
SDKs:
  iOS SDK:
    Platforms:
      - iOS 26.2
      - macOS 26.2
IDEs:
  Xcode:
    version: 26.2/17C52
    path: /usr/bin/xcodebuild
Languages:
  Ruby:
    version: 3.4.5
    path: /Users/rckm/.rbenv/shims/ruby
npmPackages:
  "@react-native-community/cli": 18.0.1
  "@react-native-community/cli-platform-apple": 18.0.1
  react: 19.0.0
  react-native: 0.79.1
iOS:
  hermesEnabled: true
  newArchEnabled: true

Description

After updating to macOS 26.3 (Tahoe) with Xcode 26.2 (Build 17C52), react-native run-ios hangs indefinitely after the build succeeds. The xcodebuild process never exits, so the CLI never proceeds to install and launch the app on the simulator.

Building from Xcode IDE (Cmd+R) works fine.

Root Cause

In buildProject.js, the CLI listens for the close event on the spawned xcodebuild process:

buildProcess.on('close', code => { ... });

The close event requires both the process to exit and all stdio streams to close. On Xcode 26.2+, xcodebuild (or its child process SWBBuildService) keeps the pipes open after build completion, so the close event never fires.

Related Issues

• Xcode 26.0.1 / 26.1 RC hanging on both macos-15-arm64 and macos-26-xlarge actions/runner-images#13264 — Xcode 26 xcodebuild hanging on CI runners
• run-ios fails sometimes but works projects builds with xcode #2057 — run-ios fails but Xcode builds fine

Reproducible Demo

Steps to Reproduce

1. Use macOS 26.3 + Xcode 26.2
2. Run npx react-native run-ios --verbose
3. Build completes — ** BUILD SUCCEEDED ** appears in output
4. CLI hangs indefinitely — never proceeds to app install/launch
5. No compiler processes running (ps aux | grep clang shows nothing)
6. xcodebuild process stays alive with SWBBuildService child that has no children of its own

Expected Behavior

After BUILD SUCCEEDED, the CLI should proceed to install and launch the app on the simulator.

Actual Behavior

The CLI hangs forever at BUILD SUCCEEDED. The xcodebuild process and its SWBBuildService child remain alive but idle.

Workaround

Patch @react-native-community/cli-platform-apple buildProject.js to detect BUILD SUCCEEDED in stdout and resolve immediately instead of waiting for the close event:

     const buildProcess = _child_process().default.spawn('xcodebuild', xcodebuildArgs, getProcessOptions(args));
     let buildOutput = '';
+    let buildResolved = false;
     buildProcess.stdout.on('data', data => {
       const stringData = data.toString();
       buildOutput += stringData;
@@ -85,8 +86,22 @@
           loader.start(`Building the app${'.'.repeat(buildOutput.length % 10)}`);
         }
       }
+      // Workaround: xcodebuild on Xcode 26.2+ may hang after build succeeds.
+      // Detect BUILD SUCCEEDED and resolve immediately instead of waiting for close.
+      if (!buildResolved && stringData.includes('BUILD SUCCEEDED')) {
+        buildResolved = true;
+        if (xcodebuildOutputFormatter) {
+          xcodebuildOutputFormatter.stdin.end();
+        } else {
+          loader.stop();
+        }
+        _cliTools().logger.success('Successfully built the app');
+        buildProcess.kill();
+        resolve(buildOutput);
+      }
     });
     buildProcess.on('close', code => {
+      if (buildResolved) return;
       if (xcodebuildOutputFormatter) {

Apply via patch-package:

npx patch-package @react-native-community/cli-platform-apple

[liamjones]

Do you get the same behaviour on a supported version of RN?

It's working fine here on macOS 26.3 + Xcode 26.2 w/ RN 0.80.3 (also unsupported, same as 0.79.x)

[rckm]

@liamjones

Do you get the same behaviour on a supported version of RN?

It's working fine here on macOS 26.3 + Xcode 26.2 w/ RN 0.80.3 (also unsupported, same as 0.79.x)

Did not tested, we are working with this version of RN right now and maybe for someone with this versions or older/newer this patch will help