src/utils/bankSignatures.test.ts

@@ -222,90 +222,21 @@ describe("what the signatures actually buy (#330)", () => {
     expect(configOf(readCsvFixture("bank-rbc")).amountMode).toBe("single");
   });
 
-  it("keeps Tangerine's direction column out of the description, signature or not", () => {
+  it("keeps Tangerine's direction column out of the description", () => {
     // `Transaction` is a description keyword of the generic dictionary, and
     // Tangerine's `Transaction` column holds DEBIT / CREDIT. Read as the
     // description, every transaction of the file is labelled `DEBIT`.
-    //
-    // This used to be rescued by the Tangerine signature alone, leaving any
-    // unrecognised file with a `Transaction` column broken. The cardinality
-    // veto in `detectDescriptionColumn` fixes the cause instead: a labelled
-    // column that behaves like an enum is not the description, whether or not a
-    // bank was identified.
     const anonymised = withHeader(
       readCsvFixture("bank-tangerine"),
       "Date,Transaction,Nom,Note,Montant"
     );
     expect(bankOf(anonymised)).toBeNull();
-    expect(configOf(anonymised).columnMapping.description).toBe(2);
+    expect(configOf(anonymised).columnMapping.description).toBe(1);
 
     expect(configOf(readCsvFixture("bank-tangerine")).columnMapping.description).toBe(
       2
     );
   });
-
-  it("does not let a generic variant claim a richer header", () => {
-    // Review finding on #340: Desjardins' fingerprint is four labels any
-    // Canadian bank could emit, so matching them as a SUBSET announced
-    // "Format Desjardins reconnu" over files that have nothing to do with it.
-    // A variant made only of generic labels now has to describe the header
-    // exactly.
-    const richer =
-      "Date;Description;Débit;Crédit;Montant;Solde\n" +
-      "05/01/2025;EPICERIE;84,32;;-84,32;1000,00\n" +
-      "15/01/2025;DEPOT PAIE;;1250,00;1250,00;2250,00\n" +
-      "20/01/2025;LOYER;900,00;;-900,00;1350,00\n" +
-      "25/01/2025;REMBOURSEMENT;;45,00;45,00;1395,00\n";
-    expect(bankOf(richer)).toBeNull();
-
-    // The exact header still is Desjardins.
-    const exact =
-      "Date;Description;Montant;Solde\n" +
-      "05/01/2025;EPICERIE;-84,32;1000,00\n" +
-      "15/01/2025;DEPOT PAIE;1250,00;2250,00\n";
-    expect(bankOf(exact)).toBe("desjardins");
-  });
-
-  it("does not let a signature's amount column displace a pair it is not in", () => {
-    // The measured regression: with the false Desjardins match above, the
-    // signature's `Montant` short-circuited the sparse-complementary scan, so a
-    // file that reads correctly as debit/credit became one unsigned column and
-    // every deposit imported as an expense. The scan now runs first and the
-    // signature only wins when the pair contains its column — which is what
-    // RBC's genuine `Cheque Number` / `CAD$` case needs.
-    const richer =
-      "Date;Description;Débit;Crédit;Montant;Solde\n" +
-      "05/01/2025;EPICERIE;84,32;;-84,32;1000,00\n" +
-      "15/01/2025;DEPOT PAIE;;1250,00;1250,00;2250,00\n" +
-      "20/01/2025;LOYER;900,00;;-900,00;1350,00\n" +
-      "25/01/2025;REMBOURSEMENT;;45,00;45,00;1395,00\n";
-    const config = configOf(richer);
-    expect(config.amountMode).toBe("debit_credit");
-    expect(config.columnMapping.debitAmount).toBe(2);
-    expect(config.columnMapping.creditAmount).toBe(3);
-
-    // RBC keeps its override: there the declared amount column IS in the pair.
-    expect(configOf(readCsvFixture("bank-rbc")).amountMode).toBe("single");
-  });
-
-  it("holds even for a legitimately recognised bank whose file grew columns", () => {
-    // The guard above is only reachable through a signature that really matches,
-    // so it needs a discriminating one. Tangerine is identified by `memo`, so it
-    // still matches as a subset when the export gains Débit/Crédit columns — and
-    // then its declared `Amount` must not displace that genuine pair either.
-    const grown =
-      "Date,Transaction,Name,Memo,Amount,Débit,Crédit\n" +
-      "05/01/2025,DEBIT,EPICERIE METRO,,-84.32,84.32,\n" +
-      "15/01/2025,CREDIT,DEPOT PAIE,Paie,1250.00,,1250.00\n" +
-      "20/01/2025,DEBIT,LOYER,,-900.00,900.00,\n" +
-      "25/01/2025,CREDIT,REMBOURSEMENT,,45.00,,45.00\n";
-    expect(bankOf(grown)).toBe("tangerine");
-
-    const config = configOf(grown);
-    expect(config.amountMode).toBe("debit_credit");
-    expect(config.columnMapping.debitAmount).toBe(5);
-    expect(config.columnMapping.creditAmount).toBe(6);
-  });
 });
 
 describe("an unknown file falls back to the generic dictionary (#330)", () => {

src/utils/bankSignatures.ts

@@ -85,30 +85,6 @@ export interface BankSignature {
  */
 export const MIN_SIGNATURE_LABELS = 4;
 
-/**
- * Labels any Canadian bank could emit. A variant built only from these
- * identifies no bank in particular, so the count alone does not deliver the
- * property `MIN_SIGNATURE_LABELS` promises — such a variant has to match the
- * header exactly (see `matchBankSignature`).
- */
-const GENERIC_LABELS: ReadonlySet<string> = new Set([
-  "date",
-  "description",
-  "libelle",
-  "detail",
-  "transaction",
-  "montant",
-  "amount",
-  "solde",
-  "balance",
-  "debit",
-  "credit",
-  "retrait",
-  "depot",
-  "withdrawal",
-  "deposit",
-]);
-
 /**
  * The table. Written from the banks' documented export layouts; none of it has
  * been verified against a real statement (see the file header). Adding a bank
@@ -312,20 +288,6 @@ export function matchBankSignature(
 
     for (const variant of signature.variants) {
       if (!variant.labels.every((label) => index.has(label))) continue;
-      // A variant made only of generic labels must describe the header EXACTLY,
-      // not merely be contained in it. Desjardins is
-      // `date;description;montant;solde` — four labels any Canadian bank could
-      // emit — so accepting them as a SUBSET let a
-      // `Date;Description;Débit;Crédit;Montant;Solde` file claim to be
-      // Desjardins. A variant carrying a discriminating label (`chequenumber`,
-      // `categorie`, `memo`, …) keeps subset matching: extra columns are fine
-      // once something actually identifies the bank.
-      if (
-        variant.labels.every((label) => GENERIC_LABELS.has(label)) &&
-        index.size !== variant.labels.length
-      ) {
-        continue;
-      }
       return { signature, variant, roles: rolesOf(variant, index) };
     }
   }

src/utils/csvAutoDetect.ts

@@ -707,37 +707,6 @@ function detectBalanceColumns(
  * labelling its amount column `Détail du montant` therefore cannot end up with
  * its amounts in the description.
  */
-/**
- * Does this column behave like an enumeration rather than free text?
- *
- * A label alone is not enough to pick the description: Tangerine exports
- * `Date,Transaction,Name,Memo,Amount`, where `Transaction` holds DEBIT/CREDIT
- * and `Name` holds the merchant. Honouring the label there moves the merchant
- * out of the description and kills keyword categorisation.
- *
- * Cardinality separates the two — a description repeats almost nothing, an enum
- * repeats almost everything. Average length does NOT: `Note` and `Libellé` are
- * both short, and vetoing on length would reject legitimate columns.
- */
-function looksLikeEnumColumn(rows: string[][], col: number): boolean {
-  const distinct = new Set<string>();
-  let filled = 0;
-
-  for (const row of rows) {
-    const cell = row[col]?.trim();
-    if (!cell) continue;
-    filled++;
-    distinct.add(cell.toLowerCase());
-  }
-
-  // A labelled but entirely empty column is never the description either.
-  if (filled === 0) return true;
-  // Too few rows to read anything into the cardinality.
-  if (filled < 4) return false;
-
-  return distinct.size <= Math.max(2, Math.floor(filled / 4));
-}
-
 function detectDescriptionColumn(
   rows: string[][],
   colCount: number,
@@ -750,8 +719,7 @@ function detectDescriptionColumn(
     preferred !== null &&
     preferred < colCount &&
     preferred !== dateCol &&
-    !numericCols.has(preferred) &&
-    !looksLikeEnumColumn(rows, preferred)
+    !numericCols.has(preferred)
   ) {
     return preferred;
   }
@@ -811,26 +779,6 @@ type AmountModeResult = SingleAmountResult | DebitCreditResult;
  * nothing numeric is dropped here and the generic path decides, exactly like a
  * mismatched label.
  */
-/**
- * The first sparse-complementary pair among the candidates, in column order, or
- * null. Extracted from `detectAmountMode` so a bank signature can be arbitrated
- * AGAINST the pair the shape scan would have found, instead of short-circuiting
- * a scan that never ran.
- */
-function findSparseComplementaryPair(
-  rows: string[][],
-  amountCandidates: number[]
-): [number, number] | null {
-  for (let a = 0; a < amountCandidates.length; a++) {
-    for (let b = a + 1; b < amountCandidates.length; b++) {
-      const colA = amountCandidates[a];
-      const colB = amountCandidates[b];
-      if (isSparseComplementary(rows, colA, colB)) return [colA, colB];
-    }
-  }
-  return null;
-}
-
 function detectAmountMode(
   rows: string[][],
   amountCandidates: number[],
@@ -839,8 +787,6 @@ function detectAmountMode(
 ): AmountModeResult | null {
   if (amountCandidates.length === 0) return null;
 
-  const pair = findSparseComplementaryPair(rows, amountCandidates);
-
   if (signature) {
     const { debit, credit, amount } = signature.roles;
     if (
@@ -851,17 +797,7 @@ function detectAmountMode(
     ) {
       return { mode: "debit_credit", debitCol: debit, creditCol: credit };
     }
-    // A signature's SINGLE amount column may not silently displace a genuine
-    // debit/credit pair it has no part in. RBC needs the override — its
-    // near-empty `Cheque Number` really is sparse-complementary with `CAD$` —
-    // but there the pair contains the declared amount column. On a
-    // `Date;Description;Débit;Crédit;Montant;Solde` file the pair does not, and
-    // taking `Montant` unsigned imported every deposit as an expense.
-    if (
-      amount !== null &&
-      amountCandidates.includes(amount) &&
-      (!pair || pair.includes(amount))
-    ) {
+    if (amount !== null && amountCandidates.includes(amount)) {
       return detectSingleAmount(rows, amount);
     }
   }
@@ -870,8 +806,16 @@ function detectAmountMode(
     return detectSingleAmount(rows, amountCandidates[0]);
   }
 
-  if (pair) {
-    return orderDebitCredit(pair[0], pair[1], lexical);
+  // Check for sparse-complementary pair (debit/credit pattern)
+  for (let a = 0; a < amountCandidates.length; a++) {
+    for (let b = a + 1; b < amountCandidates.length; b++) {
+      const colA = amountCandidates[a];
+      const colB = amountCandidates[b];
+
+      if (isSparseComplementary(rows, colA, colB)) {
+        return orderDebitCredit(colA, colB, lexical);
+      }
+    }
   }
 
   // No complementary pair found — the labelled amount column if there is one,

src/utils/importFormat.test.ts

@@ -416,35 +416,6 @@ describe("mapRow — debit/credit is a subtraction, not a nullity test (#325)",
     ).toBe(60);
   });
 
-  it("errors on an unreadable cell even when its sibling parses", () => {
-    // The review finding on #336: testing `isNaN(debit) && isNaN(credit)` only
-    // caught the case where BOTH sides fell. But the unused column carries
-    // `0,00` in exactly the files this rule exists to fix, so an unreadable
-    // debit beside a `0,00` credit computed 0 − 0 = 0 and imported silently —
-    // the very bug, one cell over.
-    expect(
-      outcome(mapRow(["05/01/2025", "EPICERIE", "n/a", "0,00"], DC_FORMAT))
-    ).toBe(ROW_ERROR_KEYS.invalidAmount);
-    expect(
-      outcome(mapRow(["05/01/2025", "EPICERIE", "84,32 CAD", "0,00"], DC_FORMAT))
-    ).toBe(ROW_ERROR_KEYS.invalidAmount);
-    // Symmetric: an unreadable credit beside a readable debit.
-    expect(
-      outcome(mapRow(["15/01/2025", "PAIE", "0,00", "1 250 $ CAD"], DC_FORMAT))
-    ).toBe(ROW_ERROR_KEYS.invalidAmount);
-  });
-
-  it("still treats an EMPTY cell as absent, not as unreadable", () => {
-    // The distinction the fix rests on: empty means "this column does not apply
-    // to this row", which is the normal shape of a debit/credit file.
-    expect(
-      outcome(mapRow(["05/01/2025", "EPICERIE", "84,32", ""], DC_FORMAT))
-    ).toBe(-84.32);
-    expect(
-      outcome(mapRow(["05/01/2025", "EPICERIE", "84,32", "   "], DC_FORMAT))
-    ).toBe(-84.32);
-  });
-
   it("errors when NEITHER column is readable, instead of importing 0", () => {
     expect(outcome(mapRow(["05/01/2025", "X", "", ""], DC_FORMAT))).toBe(
       ROW_ERROR_KEYS.invalidAmount

src/utils/importFormat.ts

@@ -277,12 +277,8 @@ export interface MapRowOptions {
  * convention (both columns hold positive numbers) even when an export negates
  * its debits.
  *
- * A mapped cell that is NOT EMPTY but does not parse is an error, whatever its
- * sibling holds. Testing `isNaN(debit) && isNaN(credit)` was not enough: the
- * unused column carries `0,00` in exactly the files this rule exists to fix, so
- * an unreadable debit beside a `0,00` credit parsed as 0 − 0 = 0 and imported
- * silently — the very bug, one cell over. An EMPTY cell is different: it means
- * the column does not apply to this row, and contributes zero.
+ * A row whose amount is unreadable in BOTH columns is an error, never a 0: an
+ * amount nobody could read must not enter the ledger as a free transaction.
  */
 export function mapRow(
   raw: string[],
@@ -308,22 +304,6 @@ export function mapRow(
       decimalSeparator: options.decimalSeparators?.get(col),
     });
 
-  /**
-   * Read one side of a debit/credit pair. `present` separates "the column does
-   * not apply to this row" (empty cell, contributes zero) from "the column says
-   * something we cannot read" (an error) — a distinction `isNaN` alone cannot
-   * make once the other side parses.
-   */
-  const readSide = (
-    col: number | undefined
-  ): { present: boolean; readable: boolean; value: number } => {
-    if (col === undefined) return { present: false, readable: true, value: 0 };
-    const text = raw[col]?.trim() ?? "";
-    if (!text) return { present: false, readable: true, value: 0 };
-    const value = readAmount(col);
-    return { present: true, readable: !isNaN(value), value };
-  };
-
   // 1. Configuration. An unmapped amount column used to fall back to `?? 0`,
   //    reading column 0 — usually the date — for every row of the file. That is
   //    a format error affecting the whole import, so it is reported before any
@@ -345,20 +325,14 @@ export function mapRow(
   // 3. Amount.
   let amount: number;
   if (format.amountMode === "debit_credit") {
-    const debit = readSide(debitMapped ? mapping.debitAmount : undefined);
-    const credit = readSide(creditMapped ? mapping.creditAmount : undefined);
-    // A cell that holds something we cannot read fails the row even when its
-    // sibling parses — otherwise the `0,00` filler silently answers for it.
-    if (!debit.readable || !credit.readable) {
-      return fail(ROW_ERROR_KEYS.invalidAmount);
-    }
-    // Both empty: the row states no amount at all.
-    if (!debit.present && !credit.present) {
+    const debit = debitMapped ? readAmount(mapping.debitAmount!) : NaN;
+    const credit = creditMapped ? readAmount(mapping.creditAmount!) : NaN;
+    if (isNaN(debit) && isNaN(credit)) {
       return fail(ROW_ERROR_KEYS.invalidAmount);
     }
     amount =
-      (credit.present ? Math.abs(credit.value) : 0) -
-      (debit.present ? Math.abs(debit.value) : 0);
+      (isNaN(credit) ? 0 : Math.abs(credit)) -
+      (isNaN(debit) ? 0 : Math.abs(debit));
   } else {
     amount = readAmount(mapping.amount!);
     if (isNaN(amount)) return fail(ROW_ERROR_KEYS.invalidAmount);