Sonu's two "transfer" payments are split by scope, Europe first and the
remainder to household, chronologically so each settles what was outstanding
when it was made. Both Europe tabs now read $0.00.
No schema change was needed and that is the point worth writing down:
split_payments has no unique constraint on linked_transaction_id, so one bank
transfer carries one row per scope and the rows re-add to the transfer --
verified, 4111 sums to $3,779.33 and 4121 to $4,794.06.
Her overall balance is unchanged at $5,428.08. Allocation moves money between
tabs, never between people; that invariance is the check to repeat on any
future re-allocation.
Trip 3, 2026-04-12 to 2026-04-28, 124 rows, $9,914.24. It was marked only by
tag 5 and so was invisible to every trip figure.
It reads at first like a sharing scope overlapping the group trip, because the
tag's earliest row is 17 March. It is not: that is a single advance booking
(Ticketmaster Nanterre), 8 more rows fall on the 12 April handover day and were
already held out of Europe 2026, and the remaining 115 run 13-28 April. A clean
sequential leg.
Also records that grouped payments need no schema change -- split_payments has
no unique constraint on linked_transaction_id, so one transfer can carry a row
per scope -- and that the 23 Apr Qantas booking is the flight to Bangkok
starting a solo leg, which is why it stays out of this trip.
The 2026-07-26 document was a proposal marked "nothing built". Everything it
described as broken is now fixed, and the fix is not the one it proposed, so
leaving it in place would misdescribe the system to whoever reads it next.
Records what the code now does: settled as the single balance gate, settled and
trip_id as orthogonal axes, settling up by recording a payment rather than
flipping a flag, and the reasons duplicates are superseded rather than deleted.
Keeps the loan design intact and clearly marked as still a proposal -- it was
never built and nothing in this work touched it.
Also records that the proposal's own recommendation not to restate history from
the CSVs was overturned, and why it was wrong: it measured the value in
balances, where it is nil, and missed it in spend, where it is $35,259.
CLAUDE.md gains the traps a new session would otherwise re-discover:
- Rules: a zero-condition rule matches everything (rule 43 would split all ~3,700
transactions); preview-then-apply-by-id is the safe pattern and why it beats
auto-applying on ingestion; how run provenance works.
- Shared expenses: transaction_splits.settled is dead data; getParticipantBalances
is correct and must not be 'fixed'; settlement cannot be attributed per trip.
- The shared loan: separate ledger, fixed 50% with a tracked receivable, why the
share must not be derived from actual payments, and why interest stays as spend.
- Extraction: balance assertions are the check that works, do not derive
opening_balance or add a totals assertion (both would be tautological), Gemini
invents summary fields it was not given, empty statements must not throw, FX is
per-date, and CSV comparisons need millisecond ordering.
The design doc records Phase 0 as done - including that the original Phase 0 plan
was wrong, since reading the code first is what prevented breaking a working
balance page.
Known Gaps lists what is open: the unbuilt phases, 11 failing assertions, the
uncategorised Up rows, and the CSVs sitting in 030490e's history.
The loan is a separate ledger, not a settlement context: a contribution must
never be able to settle a dinner.
The share is fixed at 50%, not derived from actual payments. During Sonu's leave
the obligation did not change, only the payment did - a percentage-of-actual
model would silently redefine her share as 30% and make the shortfall vanish. So
the model needs an expected schedule alongside actual contributions, with the
difference as a tracked receivable. Currently $4,000.00 over Jul 2025 - Jun 2026.
On interest: recorded the mechanics (it is debited to the loan and repaid as part
of the balance - the reconciliation is exact) alongside the counter-argument that
$16,523.64 left and bought nothing, which is what an expense is. Recommends
keeping it as spend with a fixed/discretionary grouping to address the real
concern, but flags it as a judgement call rather than settling it.
Three problems that look separate are one: the app records money moving, and
separately records who owes whom, and the two never meet.
Documents what is broken with evidence - two half-built settlement models,
settlements existing twice unlinked, and Sonu's $37,980 of loan contributions
sitting unrecognised as generic transfers - then proposes settlement contexts,
payments as transactions rather than a side table, and loan co-ownership.
Nothing built. Five open questions, two of which are decisions about the
arrangement rather than the software.
siddharthd