Michael Bolin 29bc2ad2f4 ci: scope Bazel repository cache by job (#18366) ...

## Why

The Bazel workflow has multiple jobs that run concurrently for the same
target triple. In particular, the Windows `test`, `clippy`, and
`verify-release-build` jobs could all miss and then attempt to save the
same Bazel repository cache key:

```text
bazel-cache-${target}-${lockhash}
```

Because `actions/cache` entries are immutable, only one job can reserve
that key. The others can report failures such as:

```text
Failed to save: Unable to reserve cache with key bazel-cache-x86_64-pc-windows-gnullvm-..., another job may be creating this cache.
```

Adding only the workflow name would not separate these jobs because they
all run inside the same `Bazel` workflow. The key needs a job-level
namespace as well.

## What Changed

- Added a required `cache-scope` input to
`.github/actions/prepare-bazel-ci/action.yml`.
- Moved Bazel repository cache key construction into the shared action
and exposed the computed key as `repository-cache-key`.
- Exposed the exact restore result as `repository-cache-hit` so save
steps can skip exact cache hits.
- Updated `.github/workflows/bazel.yml` to pass `cache-scope: bazel-${{
github.job }}` for the `test`, `clippy`, and `verify-release-build`
jobs.
- The scoped restore key is now the only fallback. This avoids carrying
a temporary restore path for the old unscoped cache namespace.

## Verification

- Parsed `.github/actions/prepare-bazel-ci/action.yml` and
`.github/workflows/bazel.yml` with Ruby's YAML parser.
- `actionlint` is not installed in this workspace, so I could not run a
GitHub Actions semantic lint locally.

2026-04-17 11:39:38 -07:00

..

action.yml

ci: scope Bazel repository cache by job (#18366)

2026-04-17 11:39:38 -07:00