thin-mac-ios

How far can iOS build and verification work move off Macs?

This repo is a small research harness for a hybrid answer: build iOS-simulator-shaped artifacts on Linux, then use macOS only for the runtime pieces that still require CoreSimulator.

It is deliberately not a victory lap. Linux-to-iOS cross-compilation has prior art. UIKit does not run on Linux here. Macs are still required for simulator launch, screenshots, accessibility capture, and real UI verification.

What This Tests

Linux: build the app/framework artifacts
Mac: install, launch, screenshot, capture accessibility, optionally run tests

The useful question is not "can Linux replace every Mac?" It is:

Can the Mac become a thin, scarce runtime verifier instead of the whole build box?

Current Evidence

The harness contains:

• a minimal SwiftUI iOS app fixture
• a small embedded C framework used as runtime proof
• Linux build scripts for staged Apple SDK and xtool linker inputs
• Mac verification scripts for CoreSimulator install/launch/capture
• a prior-art audit that prevents broad novelty claims

The audit currently leaves only narrow candidate deltas:

• screenshot plus accessibility tree from a Linux-built app
• Linux-built binary framework evidence visible at runtime
• a runtime-boundary map for why UIKit-on-Linux remains research

Non-Claims

This repo does not claim:

• iOS cross-compilation from Linux is new
• Linux-built .app bundles are new
• .xctestrun handoff to macOS is new
• UIKit runs on Linux
• Macs are no longer needed for iOS verification

Quick Start

Run the lightweight public checks:

make verify
make audit-prior-art

Reports land under ignored out/results/novelty-matrix.{md,json}.

Full Local Reproduction

The heavier path requires Xcode, Docker, and the xtool Darwin linker toolset. Apple SDKs, app bundles, test bundles, and signing material stay local and are ignored by git.

make package-sdk XCODE=/Applications/Xcode.app STAGE=out/stage
make stage-xtool-toolset STAGE=out/stage
make linux-build STAGE=out/stage
make mac-verify DEVICE="iPhone 17 Pro"

linux-build currently builds the sample app and embedded framework. The test sources under fixtures/ios-app/Tests document the verification surface; full test-bundle compilation is intentionally left as a next step.

Repo Layout

src/ios_linux_harness/   Python package and CLI entry points
fixtures/ios-app/        SwiftUI app, C framework, and iOS test fixtures
scripts/                 Apple/Docker-heavy workflow wrappers
docs/                    Prior art, publishing, and runtime-boundary notes
tests/                   Python tests for claims and command contracts
out/                     Ignored generated artifacts

Read Before Publishing

Read prior art, runtime boundary, and publishing before making public claims.

License: MIT.