Rather than pinning every macOS job to macOS 15, only run the older CodeQL CLI
versions (which need Xcode 16, and so macOS 15) there. Newer versions, which
support Swift 6.2, run on the latest macOS runner with its default Xcode, so we
keep exercising the common latest-CLI-on-latest-runner combination.
To express this, `sync.ts` now supports an optional per-OS-entry
`codeql-versions` filter, used by `multi-language-autodetect` to send old
versions to `macos-15-xlarge` and new versions to `macos-latest-xlarge`.
`swift-custom-build` only runs `linked`/`default`/`nightly`, which all support
Swift 6.2, so it no longer needs the Xcode 16 step or a macOS 15 pin.
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
`macos-latest-xlarge` now resolves to macOS 26, which ships only Xcode 26
(Swift 6.2) and no longer includes Xcode 16. The Swift-analysing PR checks
select Xcode 16 because CodeQL CLI versions before 2.24.0 only support Swift
up to 6.1, so `xcode-select -s /Applications/Xcode_16.app` fails on macOS 26.
Pin these checks to macOS 15, where Xcode 16 is still available, so we keep
testing the full matrix of supported CodeQL versions. This also pre-empts the
`swift-custom-build` check failing once plain `macos`/`macos-latest` migrates.
See https://github.com/actions/runner-images/issues/14167.
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
* PR checks: Only run Swift build command on MacOS
* PR checks: update to only test Swift on MacOS
* Log warning if workflow is running Swift on Ubuntu
---------
Co-authored-by: Andrew Eisenberg <aeisenberg@github.com>
