fix(core): retry bpm-detective import after transient failure

[santhiprakash]

Problem

loadBpmDetective in packages/core/src/beats/beatDetection.ts dynamically imports bpm-detective and caches the resulting promise. If that dynamic import fails once (network hiccup, bundler race, missing module), the .catch(() => null) resolved the cached promise to null and bpmDetectivePromise was never reset. Every future call to analyzeMusicFromBuffer for the rest of the session then silently skipped BPM detection.

Changes

• Reset bpmDetectivePromise to null inside the failure handler so the next call retries the import.
• Only cache the promise for the default production import; custom loader functions bypass the cache (used by tests and any future callers that need fresh control).
• Make loadBpmDetective accept an optional importFn so the retry/fallback behavior is unit-testable without mocking import().
• Add packages/core/src/beats/beatDetection.test.ts covering:
  • failure resolves to null;
  • a subsequent call retries and succeeds after a transient failure;
  • default export vs module-object fallback resolution.

Verification

• bunx vitest run src/beats/beatDetection.test.ts — 4/4 pass
• bun run build in packages/core — clean
• bun run typecheck — clean
• bunx oxlint / bunx oxfmt on changed files — clean
• Lefthook pre-commit hooks — clean

[jrusso1020]

Approved on James's go. Verified the bug + fix:

The cached-promise-never-reset bug is real — on a transient import("bpm-detective") failure the old code's .catch(() => null) left bpmDetectivePromise as a resolved-to-null promise that was never cleared, so if (!bpmDetectivePromise) stayed false and every later analyzeMusicFromBuffer silently skipped BPM detection for the rest of the session (breaking music-reactive animations / beat guides with no error).

The fix resets bpmDetectivePromise = null in the failure handler so the next call retries the import, caches only the default production import (custom loaders bypass the cache → unit-testable), and correctly distinguishes a transient import failure (reset + retry) from a successful-but-empty module (cached null, since retrying wouldn't help). Tests cover the retry-after-transient-failure path plus the default-export / module-object fallbacks. CI green.

— Rames

[jrusso1020]

Thanks for this — the fix looks good and CI is green, so it's approved. One thing is blocking the merge though: main requires signed commits, and the commit here (4f1c9b5) is currently unsigned (Unverified).

To unblock, sign the commit and force-push:

git commit --amend -S --no-edit
git push --force-with-lease

That needs commit signing configured (a GPG or SSH signing key + git config commit.gpgsign true). If the branch has more than one commit, sign them all (e.g. git rebase --exec 'git commit --amend -S --no-edit' <base>). Setup docs: https://docs.github.com/authentication/managing-commit-signature-verification

Once the commit shows as Verified, this is good to merge.