feat(parser): warn when receipt totals do not reconcile #108

Closed

TimCane wants to merge 3 commits from feat/95-reconcile-warning into main

TimCane commented

2026-07-07 12:45:24 +01:00

(Migrated from github.com)

Summary

Add ReconciliationValidator (Parsing/Validation): sum(items) + tax + tip + service vs the printed grand total, warning on a gap over a 2 minor-unit tolerance
Skip when no grand total was anchored (total is zero) or a negative amount was already parked (an unmodeled discount already explains the gap)
Wire it in last in ReceiptParseEngine.ParseTraced; cross-line, so it appends a warning but adds no trace entry
Two new fixtures: reconciling-simple (balances, no warning) and mismatch-missing-item (dropped item line fires the warning)
Three existing fixtures legitimately gain the reconcile warning:
- defune-at-quantity: printed subtotal 151.20 + service 22.68 = 173.88 total, but parsed items sum to 149.80 - a genuine ~GBP1.40 receipt/OCR discrepancy
- ding-dong-amount: "Whole @$28.00" parses as a phantom item, inflating items by 28.00 over the receipt's own 164.00 + service 16.40 = 180.40
- westminster-column-drift: the "6.50" price whose name drifted onto a separate line is parked, losing GBP6.50 from the item sum
Docs: flip reconciliation to current in docs/15, describe the validate stage in docs/06, note the validator and fixtures in docs/11

Test plan

dotnet test backend/tests/BillSplitter.Tests/BillSplitter.Tests.csproj --nologo - 93 passed
Corpus diff confirms only the three named fixtures changed; the discount receipts (crowne-plaza-iva, holland-discount, toby-carvery) stay unchanged

Closes #95

## Summary - Add `ReconciliationValidator` (`Parsing/Validation`): `sum(items) + tax + tip + service` vs the printed grand total, warning on a gap over a 2 minor-unit tolerance - Skip when no grand total was anchored (total is zero) or a negative amount was already parked (an unmodeled discount already explains the gap) - Wire it in last in `ReceiptParseEngine.ParseTraced`; cross-line, so it appends a warning but adds no trace entry - Two new fixtures: `reconciling-simple` (balances, no warning) and `mismatch-missing-item` (dropped item line fires the warning) - Three existing fixtures legitimately gain the reconcile warning: - `defune-at-quantity`: printed subtotal 151.20 + service 22.68 = 173.88 total, but parsed items sum to 149.80 - a genuine ~GBP1.40 receipt/OCR discrepancy - `ding-dong-amount`: "Whole @\$28.00" parses as a phantom item, inflating items by 28.00 over the receipt's own 164.00 + service 16.40 = 180.40 - `westminster-column-drift`: the "6.50" price whose name drifted onto a separate line is parked, losing GBP6.50 from the item sum - Docs: flip reconciliation to *current* in docs/15, describe the validate stage in docs/06, note the validator and fixtures in docs/11 ## Test plan - `dotnet test backend/tests/BillSplitter.Tests/BillSplitter.Tests.csproj --nologo` - 93 passed - Corpus diff confirms only the three named fixtures changed; the discount receipts (crowne-plaza-iva, holland-discount, toby-carvery) stay unchanged Closes #95

TimCane commented

2026-07-07 15:54:53 +01:00

(Migrated from github.com)

Closing: the reconcile signal this adds already exists. SplitCalculator computes the items-vs-total checksum (bill.checksumMinor), and ChecksumBanner surfaces it on the review screen - formatted and live as the host edits ("Items + extras are X over/under the printed total").

ReconciliationValidator was a third copy of that arithmetic, and routing it through ocr.warnings misframed it in ParserWarnings as a skipped line with raw minor units. After merging main and dropping the warning, this branch nets to zero diff vs main, so there is nothing left to merge.

Closing: the reconcile signal this adds already exists. `SplitCalculator` computes the items-vs-total checksum (`bill.checksumMinor`), and `ChecksumBanner` surfaces it on the review screen - formatted and live as the host edits ("Items + extras are X over/under the printed total"). `ReconciliationValidator` was a third copy of that arithmetic, and routing it through `ocr.warnings` misframed it in `ParserWarnings` as a skipped line with raw minor units. After merging main and dropping the warning, this branch nets to zero diff vs main, so there is nothing left to merge.