[isaacroldan]

WHY are these changes introduced?

Related to https://community.shopify.dev/t/high-cpu-due-to-file-watcher-for-app-dev-command/38774/4

app dev traverses Cargo build output, Function output directories, and CLI temporary files before it filters file events. This creates unnecessary file watchers and polling work.

WHAT is this pull request doing?

Exclude complete Cargo target directories when their parent contains Cargo.toml, Function output directories, .shopify files, Finder metadata, and editor temporary files before Chokidar traverses them. Other source and imported files in target, dist, and generated remain watched.

Refresh Function output rules when the app reloads, without restarting the watcher. Real-watcher tests use bounded readiness checks and guaranteed cleanup.

Validation: 51 app-event tests, a separate polling-mode probe, app type checking, and changed-file lint passed. The reload regression fails with the old matcher.

How to manually test your changes?

1. Run pnpm shopify app dev --path <app> for an app with a Rust Function and a UI extension. Edit Rust source and confirm that the Function rebuilds.
2. Run a Cargo build in another terminal and check watcher CPU use while build output changes.
3. While the dev session runs, generate another Function with pnpm shopify app generate extension --path <app>. Edit its source and confirm that it builds.
4. Import a UI module from a shared target/release, dist, or generated directory outside the extension. Edit that module and confirm that the extension rebuilds.

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

[gonzaloriestra]

/snapit

[github-actions]

🫰✨ Thanks @gonzaloriestra! Your snapshot has been published to npm.

Built from bdb2926fbceda04fb278c9656c7b23e79486a683. Workflow run.

Test the snapshot by installing your package globally:

pnpm i -g --@shopify:registry=https://registry.npmjs.org @shopify/cli@0.0.0-snapshot-20261023095012

Caution

After installing, validate the version by running shopify version in your terminal.
If the versions don't match, you might have multiple global instances installed.
Use which shopify to find out which one you are running and uninstall it.

[gonzaloriestra]

Tophatted and confirmed that it fixes the original issue 👌