waggle-os/docs/redesign-warm-hive/smoke-20260615/FILE-CHOOSER-ROOT-CAUSE.md

Root-cause: "file-chooser storm" during the PR1 live smoke

Verdict: dev/automation-only artifact. NOT a user-facing bug, NOT caused by PR1, no code fix warranted.

Symptom

During the PR1 Playwright smoke, navigating a freshly-started Vite dev server (localhost:8081/?skipOnboarding=true) surfaced 5+ pending "file chooser" modal states on load, blocking screenshots until each was cancelled (fileChooser.setFiles(undefined)). 13 console errors also appeared.

Investigation (systematic-debugging skill)

Phase 1 — static analysis (exhaustive):

• Enumerated every <input type="file"> in apps/web/src: BackupApp (×2), SettingsApp, ChatApp, FilesApp/FileActions, ImportStep, HarvestTab. All are hidden and clicked only via an explicit user-button onClick. None mount on /home.
• Enumerated every .click() call in apps/web/src: all are either <a download> anchor exports (fire a download event, not a file chooser) or the user-bound file-input clicks above. No useEffect/mount-time file-chooser trigger exists.
• ?skipOnboarding=true bypass only writes {completed:true, tier:'power'} to localStorage — no file interaction.

Phase 3 — reproduction (decisive):

• Re-ran the same URL against the steady-state Vite (:8080, deps already optimized): landed cleanly on /home with no file-chooser modal state and no error flood.
• DOM inspection on /home: input[type=file] count = 0, activeElement = BODY.

Root cause

The artifact is tied to Vite's first-run dependency re-optimization on a cold dev server, which forces a mid-render full-page reload while Playwright is driving the page. Under that transient + automation, Playwright surfaced phantom file-chooser pending-operations. It does not occur on a warm dev server, in the production build, or in the Tauri desktop binary — and there is no application code path that opens a file dialog without a user gesture (which real browsers block anyway).

The 13 console errors were a separate smoke-setup artifact: the :8081 frontend calling the founder's :8080/:3333 sidecar with a mismatched session (cross-instance auth).

Action

None on the product. For future smokes: warm the dev server (let dep optimization finish) before driving Playwright, or smoke the production build / an already-running dev server.