Add jobs for Linux static SDK and Wasm SDK builds

[jrflat]

This PR adds linux-static-sdk-build and wasm-sdk-build jobs to the swift_package_test.yml workflow. These jobs use a new script install-and-build-with-sdk.sh that finds the latest Linux static or Wasm SDKs for the given Swift version, downloads a matching toolchain if needed, and runs <swift-executable> build --swift-sdk <sdk-name> <flags>.

The script is called with the following parameters

bash ./install-and-build-with-sdk.sh [--static] [--wasm] [--flags="<build-flags>"] <swift-version>

such as

bash ./install-and-build-with-sdk.sh --static --flags="--verbose" nightly-6.2

The swift_package_test.yml workflow includes new inputs:

• enable_linux_static_sdk_build: boolean (default: false)
• linux_static_sdk_versions: string (default: "[\"nightly-6.2\"]")
• linux_static_sdk_pre_build_command: string (default: "")
• enable_wasm_sdk_build: boolean (default: false)
• wasm_sdk_versions: string (default: "[\"nightly-6.2\"]")
• wasm_sdk_pre_build_command: string (default: "")

The jobs run on a Ubuntu container with the provided Swift version to maximize the chance that the installed toolchain snapshot will match the static or Wasm SDK snapshot. However, even if they don't match, the script will find and download the correct toolchain and use the correct Swift executable in the build command. For instance, I tested a variety of versions like 6.0, 6.1, and nightly-6.2 on a container with a Swift main snapshot, and the script downloads and uses the respective 6.0, 6.1, and nightly-6.2 toolchains to build.

Note that inputting an older Swift version where the corresponding SDK isn't available, such as wasm_sdk_versions: "[\"6.0\"]", will still result in an error.

[shahmishal]

Thank you for adding support for static sdk, can you please add a check in https://github.com/swiftlang/github-workflows/blob/main/.github/workflows/pull_request.yml to make sure we don't regress the static sdk check in the future.

[jrflat]

Yes will do. I think I'll also add support for more Swift versions, so we could also test with the 6.1 release static SDK, etc. if desired

[jrflat]

Will change this to swiftlang/github-workflows/refs/heads/main before merging, but I wanted to get testing in this PR.

[jrflat]

Updated in 85552f9

[jrflat]

Will remove these before merging so that only the default versions (nightly-6.2) are tested, but I wanted to get more extended coverage when testing this PR.

[jrflat]

Removed in 85552f9

[jrflat]

Seems like #140 should prevent the Xcode 16.0 and 16.1 failures (by removing them).

[jrflat]

Updated the script URL to point to swiftlang:main branch instead of jrflat:linux-static-sdk-build to prepare for merge. The jobs are failing on this PR but will pass in future PRs once the script is merged.

Passing tests from the previous commit for reference: https://github.com/swiftlang/github-workflows/pull/142/checks?sha=47757d7ea31678a1e11791bf5a9fd248659508c5

[jrflat]

@shahmishal if the above merge strategy sounds good to you would you mind merging this?

Another option could be to merge the script first, and then enable the PR tests separately, but I figured it would be easier to do it in one go.

[shahmishal]

thanks!