CI/Build improvements: prepack scripts and yalc workflow fixes

[justin808]

Summary

Improve CI workflows and build scripts for better reliability and consistency.

Background

PR #1896 contained several CI and build improvements. This issue tracks extracting those that are still relevant for current master.

Proposed Changes

1. Fix Prepack Scripts

• Ensure prepack scripts use yarn instead of npm
• Consistency across all package.json files
• Update package-scripts.yml

Files:

package-scripts.yml
packages/react-on-rails/package.json
packages/react-on-rails-pro/package.json

2. Yalc Workflow Fixes (if still needed)

• Fix CI frozen-lockfile errors with yalc workflow
• Remove --frozen-lockfile from dummy app install after yalc
• Update Pro integration workflow

Files:

.github/workflows/pro-integration-tests.yml

3. ReScript Build Step (if still using ReScript)

• Add ReScript build step before starting development server
• Ensure proper build order

Note: Verify if ReScript is still in use before implementing this.

Investigation Needed

Before implementing, check:

1. Are the yalc workflow issues still present on current master?
2. Is ReScript still being used in the codebase?
3. Are prepack scripts still using npm anywhere?

Testing

• Verify yalc workflow works in CI
• Test prepack scripts locally
• Ensure all CI workflows pass
• Check Pro integration tests

Related

• Extracted from closed PR Upgrade Shakapacker to 9.3.0 #1896
• May be already fixed on master - needs investigation

Labels

ci, build

[justin808]

Deep-dive triage pass (2026-03-22):

• Domain: ci/tooling
• Labels/Priority signals: enhancement, P3
• Current PR coverage: no open PR currently linked
• Proposed next step: add this to the new triage PR stack so it has explicit implementation ownership.

Question: Should this run in the CI/tooling maintenance wave, or be deferred behind release-critical runtime work?

[justin808]

Closing — yalc was entirely removed in PR #2338. pnpm workspaces now handle all local package linking via pnpm-workspace.yaml.