Checks fails on push to main: setup cache key collision between workflows

[pomfrida]

Problem

The Checks run on push to main for 1243030 (#5209) failed in Check AI component index freshness, reporting all 23 /next components as missing from documentation/AI-COMPONENT-INDEX.md — even though the committed file on main is up to date.

Root cause

Five workflows call _setup.yml with the same cache key ${{ github.sha }} but different checkout_paths:

Workflow	checkout_paths
checks.yaml	packages apps scripts .github documentation
publish_storybook.yaml	packages apps scripts
publish_core_react.yaml	packages scripts
publish_data_grid.yaml	packages scripts
publish_lab.yaml	packages scripts

GitHub Actions caches are immutable — the first save wins. On this push, both Checks and Publish core-react storybook started at 09:42:29. The storybook setup saved the cache first (its workspace has no documentation/), and the Checks setup logged:

Failed to save: Unable to reserve cache with key 1243030…, another job may be creating this cache.

The Process packages job in Checks then restored the storybook variant, so documentation/AI-COMPONENT-INDEX.md did not exist in the workspace and generate:component-index --check treated the committed file as empty.

This was the first push to main since the freshness check landed (#5079) that also matched the storybook publish path filter — earlier docs/ci-only pushes never raced.

Fix

Give each workflow a unique setup cache key suffix, the same pattern publish_icons.yaml (-setup-icons) and publish_tokens.yaml (-setup-tokens) already use.

[claude]

These issues may be related to this cache-key collision:

• Generate AI component index for /next components #4890 — Generate AI component index for /next components (closed): introduced the AI-COMPONENT-INDEX.md and the freshness check (via chore: add generated AI component index for /next #5079) that this failure originates from.
• ci: speed up PR checks workflow #4624 — ci: speed up PR checks workflow (open): directly calls out that _setup.yml uses github.sha as the cache key, the same root cause behind this collision — any fix here likely overlaps.

This comment was generated by an LLM and may be inaccurate. Please verify that the linked issues are actually relevant.