Templates: failed seed left marked up-to-date forever

Symptom

scripts/prepare-templates.ts creates a tpl-* branch, then seeds it. If create succeeds and a later step fails (awaitConnectionString, resolveBranchDsn, or seedTemplate), the next deploy/run sees the branch name in listBranches() and logs it as up-to-date, skipping recreate/re-seed.

Learners who fork that template get an empty or broken sandbox for that lesson.

Red loop (logic already exercised)

1. Create template name not in existing → createBranch succeeds → add name to Xata.
2. Seed (or DSN) throws → script exits non-zero.
3. Re-run: existing.has(name) → skip with (up-to-date).

Where

• scripts/prepare-templates.ts (~lines 219–237) — existence check only; no “seeded successfully” marker / delete-on-failure

Suggested direction

On failure after create: delete the branch (or mark incomplete). On success-only: treat as up-to-date. Alternatively re-seed / verify seed before skipping.

Notes

Diagnosed with /diagnosing-bugs. Deploy impact if template prep fails mid-lesson after the branch already exists.

Read scripts/prepare-templates.ts around lines 219–237 and trace the create, DSN, and seed steps. Verify the failure path after branch creation, then ensure a failed preparation is not treated as up-to-date on the next run. Done means a failed seed can be retried and a successfully prepared template remains safely skipped.