[github-actions]

WHY are these changes introduced?

getAssetsDeletedFromRemote and getAssetsChangedOnRemote in theme-polling.ts each hand-rolled the same "index checksums by key" Map construction, and each assigned its filter result to a named local only to return it on the next line. One of the two filter callbacks also relied on an implicit undefined fall-through to mean "exclude this asset", which is easy to misread as a missing return.

WHAT is this pull request doing?

Extracts the shared checksumsByKey helper used by both remote-checksum diffing functions, returns the filter results directly instead of via single-use locals, and makes the exclusion case in getAssetsChangedOnRemote an explicit false.

Behavior is unchanged. The deleted-asset check moves from map.get(key) === undefined to map.has(key), which is equivalent here because the map values are always Checksum objects and never undefined.

How to manually test your changes?

shopify theme dev --theme-editor-sync

Edit a file in the theme editor and confirm the change syncs down locally, then delete a file in the theme editor and confirm it is removed locally.

Checklist

• I've considered possible cross-platform impacts (Mac, Linux, Windows)
• I've considered possible documentation changes
• I've considered analytics changes to measure impact
• The change is user-facing — I've identified the correct bump type (patch for bug fixes · minor for new features · major for breaking changes) and added a changeset with pnpm changeset add