Software EngineeringOpen accessPublished 3 Oct 2026
Sets up GitHub Actions CI for Swift Package Manager projects (minimal macOS build+test workflow, Xcode/macOS version matrix, .build caching, runner image selection) and diagnoses/prevents environment-dependent Swift bugs that pass locally but fail on CI (JSONDecoder ISO8601 fractional seconds, NumberFormatter locale grouping, Date/timezone assumptions, locale-dependent string sorting, hardcoded paths, filesystem case-sensitivity, Bundle.module resource paths, Decimal/Double formatting). Use when asked for "swift CI", "GitHub Actions swift test", when "tests pass locally but fail on CI", or when debugging "locale" or "Foundation differences" between macOS/Xcode versions. T…
