Reject unrelated numbers and negative values in revenue-share text

src/schema/pay.ts

@@ -236,8 +236,24 @@ const REVENUE = /\b(rev(?:enue)?(?:\s+share)?|profit\s+share|of\s+(?:the\s+)?rev
 
 function parseRevenueShare(text: string): PayLine | string | null {
   if (!REVENUE.test(text) || !/%|percent/i.test(text)) return null;
-  const numbers = [...text.matchAll(/(\d+(?:\.\d+)?)\s*(?:%|percent)?/g)].map((m) => Number(m[1]));
-  if (numbers.length === 0) return 'A revenue share needs a percentage: "10% revenue share".';
+  const matches = [...text.matchAll(/\d+(?:\.\d+)?/g)];
+  if (matches.length === 0) return 'A revenue share needs a percentage: "10% revenue share".';
+  const firstMatch = matches[0]!;
+  const secondMatch = matches[1];
+  // A number in surrounding prose is not a range endpoint, and a minus
+  // before the first number must not silently turn a negative share positive.
+  const prefix = text.slice(0, firstMatch.index).trim();
+  const separator = secondMatch === undefined
+    ? null
+    : text.slice(firstMatch.index! + firstMatch[0].length, secondMatch.index);
+  if (
+    matches.length > 2 ||
+    /[-\u2212]$/.test(prefix) ||
+    (separator !== null && !/^\s*(?:%|percent)?\s*(?:-|\u2013|\u2014|to)\s*$/i.test(separator))
+  ) {
+    return 'Write one non-negative revenue percentage or a range, such as "5-10% revenue share".';
+  }
+  const numbers = matches.map((match) => Number(match[0]));
   const upTo = /^\s*(up\s*to|max(?:imum)?)\b/i.test(text);
   const from = /^\s*(from|at\s+least|min(?:imum)?)\b/i.test(text) || /\+\s*%?/.test(text);
   const [first, second] = numbers;

test/pay-revenue-text.test.ts

@@ -0,0 +1,37 @@
+import assert from 'node:assert/strict';
+import { test } from 'node:test';
+import { parsePayLine, formatPayLine, normalisePay } from '../src/schema/pay.ts';
+
+for (const text of [
+  '-10% revenue share',
+  'from -10% revenue share',
+  '5% - -10% revenue share',
+  '10% revenue share after 12 months',
+  '10% revenue share after 6 months',
+  '5-10-15% revenue share',
+]) {
+  test(`rejects ambiguous or negative revenue share: ${text}`, () => {
+    assert.equal(typeof parsePayLine(text), 'string');
+    assert.equal(typeof normalisePay({ pay: text }), 'string');
+  });
+}
+
+for (const [text, min, max] of [
+  ['10% revenue share', 10, 10],
+  ['5-10% of revenue', 5, 10],
+  ['5% - 10% revenue share', 5, 10],
+  ['5 to 10 percent profit share', 5, 10],
+  ['Up to 10% revenue share', null, 10],
+  ['From 10% revenue share', 10, null],
+  ['10+% revenue share', 10, null],
+  ['0.5-1.25% revenue share', 0.5, 1.25],
+] as const) {
+  test(`preserves valid revenue share and round trip: ${text}`, () => {
+    const parsed = parsePayLine(text);
+    assert.notEqual(typeof parsed, 'string');
+    if (typeof parsed === 'string') throw new Error(parsed);
+    assert.equal(parsed.min, min);
+    assert.equal(parsed.max, max);
+    assert.deepEqual(parsePayLine(formatPayLine(parsed)), parsed);
+  });
+}