[cerisier]

Motivation

Consumers currently have to repeat MSVC toolset, compiler-compatibility, redistributable, Windows SDK package, and SDK include-tree versions outside the repositories that resolve them. Those copies can drift when the configured Microsoft payloads change.

Contract

The generated @msvc_runtime and @windows_sdk repositories are the authoritative source for their resolved versions. Consumers can load public Starlark constants instead of reconstructing paths or hard-coding versions.

MSVC 14.x toolset versions map to their corresponding 19.x compiler compatibility version. The repository rule validates this supported format rather than silently deriving an unknown future mapping. Redistributable and SDK include versions remain independently discovered from the extracted payloads.

Change

• generate and export @msvc_runtime//:versions.bzl with MSVC_TOOLSET_VERSION, MSVC_COMPATIBILITY_VERSION, and VC_REDIST_VERSION;
• generate and export @windows_sdk//:versions.bzl with WINDOWS_SDK_VERSION and WINDOWS_SDK_INCLUDE_VERSION;
• document the public constants and their meanings;
• add an end-to-end comparison covering all resolved values.

Tests

• bazel test --repo_env=BAZEL_MSVC_RUNTIME_VISUAL_STUDIO_EULA=1 //:smoke_test //:resolved_versions_test from e2e/smoke
• bazel test //:registered_msvc_runtime_extension_without_eula_test from e2e/msvc_runtime_lazy
• bazel test //...
• bazel run //.github/workflows:buildifier.check
• bazel run //:gazelle -- -mode=diff