## Problem
When a transaction is created (or deleted) with the **update balance**
option on
a **past date**, only that day's balance snapshot was adjusted. Balances
are
stored as sparse per-date snapshots read with carry-forward semantics
(`BalanceLookup::getBalanceAt` returns the most recent snapshot
on/before a
date), so later snapshots — most importantly *today's current balance* —
kept
their stale value.
Reproduction: yesterday = 10, today = 10. Add a −5 expense dated
yesterday with
"update balance" on. Before this fix, yesterday became 5 but today
stayed 10.
Expected: both become 5.
## Fix
`ManualBalanceAdjuster` now shifts the transaction's own day **and every
later
snapshot** by the same delta, on both create and delete:
- `applyCreatedTransaction` seeds a snapshot on the transaction's date
from the
carried-forward balance (when none exists yet), then increments that
date and
all later snapshots by `+amount`.
- `reverseDeletedTransaction` now applies the exact inverse from the
transaction's own date forward (previously it only ever adjusted
*today*,
which left the past day stale and would corrupt a create→delete
round-trip of
a back-dated transaction).
The shared forward-shift is extracted into `shiftBalancesFrom(delta)`,
used by
both paths.
## Also in this PR (small UI fix)
The balance history modal (`BalancesModal`) rendered each row's
date/balance
text top-aligned while the action icons were centered, because the base
`TableCell` defaults to `align-top`. Center the data-row cells so every
column
lines up. Scoped to this modal — the shared `TableCell` is untouched.
## Notes / intended semantics
- **Later user-set balances shift too.** Snapshots are treated as points
on one
running balance, so backfilling/removing a past transaction moves
today's
balance as well. That is exactly the reported expectation ("today should
also
change"). We deliberately do **not** try to distinguish "anchor"
snapshots
(a value the user reconciled by hand) from transaction-derived ones —
there is
no such distinction in the schema, and adding one is a separate product
decision.
- **Pre-existing, out of scope:** editing a transaction's amount/date
never
adjusts balances (`amount`/`transaction_date` aren't editable via
`UpdateTransactionRequest`), and the create vs. delete "update balance"
toggles are independent — creating with the box off but deleting with it
on
can over-correct. Neither is introduced here.
## Tests
- New: creating a past-dated transaction updates that date **and** every
later
balance (the exact reported bug).
- Rewrote the delete test to assert the reverse propagates from the
transaction's date forward (the old test encoded the now-removed "always
write
today" behavior).
- Full `TransactionTest` suite green (49 passed).
## QA
Verified end-to-end in the running app on a manual account (yesterday =
10.00,
today = 10.00): created a −5.00 expense dated yesterday with "update
balance"
on. The balance history modal shows **both** records — yesterday and
today —
drop from 10.00 to 5.00, and the DB confirms both snapshots = 500.
## Demo
https://github.com/user-attachments/assets/18aa043d-37aa-4073-990c-a269c982a818
9312d24f93