Enhanced TurboSnap: Trace dependency changes instead of bailing out

[ghengeveld]

Currently (as of v6.11.0), TurboSnap bails out if it finds a dependency-related change in package.json, or any change to package-lock.json or yarn.lock. Although this is much better than bailing out on any change to package.json, this behavior is still lacking because it means we do a full rebuild even if the updated dependency isn't used in any or some of the stories (directly or indirectly).

This update avoids bailing out of TurboSnap for changes to lock files. Instead it parses and compares lock files to their previous (baseline) version, to retrieve a set of changed dependency names. Those dependency names are then cross-referenced with the Webpack dependency tree to trace those changed dependencies to the story files that are affected by them. This essentially uses the existing "changed files" behavior of TurboSnap, but extends it to include files in node_modules (for dependencies we know have been added/updated/removed) in the set of changed files.

If we fail to find or parse a lock file (or its previous version) then we fall back to the v6.11.0 behavior of bailing out on any dependency-related change to package.json.

How to test

Scenarios to test:

• Component change => tests are skipped as usual (except for the changed component)
• npm dependency update (package-lock.json change) => only tests stories which use this dependency
• Yarn dependency update (yarn.lock change) => only tests stories which use this dependency
• package.json dependency change (lockfile missing) => bails out with changedPackageFiles
• package.json other change (lockfile missing) => skips all tests
• package.json dependency change (lockfile unchanged) => skips all tests
• Monorepo setup (Storybook / package.json in subdirectory):
  • Component change => tests are skipped as usual (except for the changed component)
  • Dependency change in Storybook project (local lockfile change) => skips tests that don't use this dependency
  • Dependency change in another project (root lockfile change) => skips tests that don't use this dependency

[tmeasday]

This is awesome @ghengeveld! 🚀

I just want to make sure we get the replacement builds thing right. Is it possible to get a test for those in? I'm not really seeing a full E2E test for this, is that too difficult?

[skitterm]

Nice work, thanks for taking this on. I assume we'll want to also (not in this PR) change the TurboSnap docs related to full rebuilds.

[skitterm]

Looks great to me, thanks for all the comments in the tests!

[ghengeveld]

All tested ✅ Wow!
I used the shapes-light and chromatic projects.