From 21c72f9fe0ddbfe5168875aa5db14f90b7cdccf2 Mon Sep 17 00:00:00 2001 From: Russell Keith-Magee Date: Tue, 14 Jul 2026 06:38:43 +0800 Subject: [PATCH] [3.13] gh-153631: Ensure iOS simulator is running before starting build (GH-153632) Makes a small change to the iOS build script to improve build stability. xcodebuild doesn't guarantee that the CoreSimulatorService is running before starting a simulator. If the service isn't running, xcodebuild reports that no simulators are available, and fails to start the test app. However, simctl blocks until the simulator is available, and simctl is used to evaluate the default simulator. So - the iOS build script now unconditionally determines the default simulator, even if a specific simulator is requested. (cherry picked from commit 2dc1a91af801ea896e21f6c6e6cc41f57e8268d9) Co-authored-by: Russell Keith-Magee --- iOS/testbed/__main__.py | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/iOS/testbed/__main__.py b/iOS/testbed/__main__.py index 7fddc3c026d3d7a..4caa9e3dfdb6816 100644 --- a/iOS/testbed/__main__.py +++ b/iOS/testbed/__main__.py @@ -220,8 +220,14 @@ def run_testbed(simulator: str | None, args: list[str], verbose: bool = False): update_test_plan(location, args) print(" done.") + # xcodebuild doesn't guarantee that the CoreSimulatorService daemon is + # running prior to using a simulator, but calling `xcrun simctl list` does. + # Determining the default simulator that *would* be used is a cheap action; + # so use that as a way to ensure that the CoreSimulatorService daemon is + # running. + default_simulator = select_simulator_device() if simulator is None: - simulator = select_simulator_device() + simulator = default_simulator print(f"Running test on {simulator}") xcode_test(location, simulator=simulator, verbose=verbose)