[richshaw]

Fixes #503 (part 3 of 3; parts 1 and 2 are #530 and #533). Part of #498. Stacked on #533; the diff here is only the merge.

What changes

When a draft has slots that are copies of each other, the review page's notice ("3 slots are the same: Setup · Thu, May 2. One slot for 3 people does the same job.") now has Merge into one slot:

• One slot keeps the copies' total spots (no limit if any of them had none). The others are deleted.
• For numbered rows ("Helper 1", "Helper 2", "Helper 3", each for one person), the kept slot takes the shared value ("Helper"). The notice already says "If they're the same job, one slot for 3 people does it."
• The line above the list says "Merged 3 slots into one for 3 people." (or "… with no limit.") with Undo. Undo puts every copy back where it was, with its values and spots.

This was the issue's check 4: "one slot whose capacity is the sum of theirs, with the others deleted … in one transaction with one activity row, through a small mergeSlots service."

How it works

• New services in src/services/slot-merge.ts:

  • mergeSlots: one transaction and one slot.merged row. It locks the signup, then its slots, in the documented order. Under the lock it refuses:

    • anything but a draft;
    • a slot from another signup;
    • a closed slot;
    • any sign-up on them;
    • slots that are no longer copies of each other. findDuplicateSlots runs again on the locked rows, so a copy renamed since the notice was shown isn't deleted.

    Capacity is worked out from the locked rows, never taken from the caller.

  • unmergeSlots: the exact inverse, with one slot.unmerged row. The undo carries the kept slot's updatedAt from the merge. It is refused when that has changed, which covers:

    • a later rename or date change;
    • a capacity change;
    • a reorder that moved it;
    • an Undo that already ran.
• One insert path. insertSlot in slots.ts is the insert path for addSlot, addSlotsBulk and the undo, so restored rows get their ref and slot_at the same way.
• Wiring. The page's fix machinery from Fix four kinds of draft problem in one tap on the review page, with Undo #533 gains the duplicate_slots kind. The request must match a fresh notice by its exact set of ids. The undo is exactly what mergeSlots returned, checked against the strict unmerge schema on the way back.
• Refusals in plain words:
  • a copy deleted, closed, booked or changed since: "That changed since you opened this page, so nothing was done."
  • the kept slot changed: "That changed again since, so it can't be undone."
  • not a draft any more: "This signup isn't a draft any more. Change it in the builder."
  • anything no change could cause: "Couldn't fix that. Try again."
• Telemetry: slot.merged ({ slotId, mergedSlotIds, capacity }) and slot.unmerged ({ slotId, restoredSlotIds, capacity }), plus review.notice_accepted / review.fix_undone with kind duplicate_slots. docs/telemetry.md lists them.

Help

"Create and publish your first signup": "For slots that are copies of each other, choose Merge into one slot: one slot takes all their spots." A new walkthrough test merges copies on the review page and undoes it.

Checks

• pnpm lint && pnpm typecheck && pnpm knip && pnpm test: pass (1486)
• pnpm test:db: pass (592)
• pnpm build && pnpm budgets: pass (/app/signups/[id] 112.7 / 113 kB, unchanged)
• Full e2e (chromium): 62 passed

Tophat and the code-review fixes are in the comments.

🤖 Generated with Claude Code

https://claude.ai/code/session_01BTvMvHZ4i4FWQFAsxcr5Zm

[richshaw]

Tophat: pass, in the running app with made-up data (pat@example.com).

• Exact copies: three "Setup · Thu, May 2" rows for one person each. Merge into one slot shows "Merged 3 slots into one for 3 people." and focus moves to Undo. The list shows one "Setup · 3 people", and the "dates repeat" notice goes with the copies. Undo puts the three rows back in place.
• Numbered rows: "Helper 1/2/3" become "Helper · 3 people". Undo brings back Helper 1, 2, 3 in order.
• Undo after a later edit (on 4baff66): merge, then another tab renames the merged slot to "Setup crew" with its spots unchanged. Undo now says "That changed again since, so it can't be undone." and the rename stays. Before this push, Undo would have quietly put "Setup" back.
• Activity: slot.merged, then review.notice_accepted {kind: duplicate_slots}, then slot.unmerged, then review.fix_undone. No console errors.

Code review on this PR. Fixed in aeaa678 and 4baff66:

• One version check for Undo. The undo carries the kept slot's post-merge updatedAt, and unmergeSlots refuses once it differs. This covers:

  • a later rename or date change;
  • a capacity change;
  • a reorder that moved the slot;
  • a repeated or concurrent Undo, including slots with no limit.

  It replaces the capacity-sum check, the activity-log lookup (which also lacked a workspace condition), and the page-side copies heuristic (which wrongly refused a first Undo once a new copy had been added).

• Merge re-checks under its lock that the slots are still copies: findDuplicateSlots runs on the locked rows. A copy renamed since the notice was shown is refused, and nothing is deleted.

• Honest refusals. Only refusals a concurrent change can cause read as "changed since". A values or schema refusal says "Couldn't fix that. Try again." A merge error's field no longer reaches the rename branch.

• Simplifications: mergeRequestFor sends values only for numbered rows. The unmerge schema is .strict() with no per-row status, and insertSlot lost its unused status parameter.

Left as is: restore order for copies that share a sortOrder. Copies made by createSignup or addSlotsBulk have distinct ones, and a reorder that touched the kept slot now refuses Undo.

Checks on 4baff66: lint, typecheck, knip, unit (1486), test:db (592), build + budgets (/app/signups/[id] 112.7 / 113 kB), e2e 62/62.

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[richshaw]

Closing without merging, as part of the redesign in #498. The branch stays: mergeSlots and unmergeSlots in src/services/slot-merge.ts and their tests are meant to be reused.

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