Manually map Safari versions in getMatchingBrowserVersion

This is not ideal, but it fixes the problem now. Tests are in place to
ensure that if we fix it in some other way, there's no observable
difference.

scripts/release/mirror.test.ts

@@ -65,13 +65,13 @@ describe('mirror', () => {
           ['1.2', '1'],
           ['1.3', '1'],
           ['2', '1'],
-          ['3', '2'], // wrong, should be 1
+          ['3', '2'],
           ['3.1', '2'],
-          ['4', '3.2'], // ambiguous
+          ['4', '3.2'],
           ['5', '4.2'],
           ['5.1', '6'],
           ['6', '6'],
-          ['7', '8'], // wrong, should be 7
+          ['7', '7'],
           ['8', '8'],
           ['9', '9'],
           ['9.1', '9.3'],
@@ -85,7 +85,7 @@ describe('mirror', () => {
           ['13.1', '13.4'],
           ['14', '14'],
           ['14.1', '14.5'],
-          ['15', '15.1'], // wrong, should be 15
+          ['15', '15'],
           ['15.1', '15.1'],
           ['15.2', '15.2'],
           ['15.3', '15.3'],

scripts/release/mirror.ts

@@ -15,6 +15,32 @@ import compareVersions from 'compare-versions';
 import bcd from '../../index.js';
 const { browsers } = bcd;
 
+/**
+ * @typedef {import('../types').Identifier} Identifier
+ * @typedef {import('../types').SupportStatement} SupportStatement
+ * @typedef {import('../types').ReleaseStatement} ReleaseStatement
+ */
+
+const matchingSafariVersions = new Map([
+  ['≤4', '≤3'],
+  ['1', '1'],
+  ['1.1', '1'],
+  ['1.2', '1'],
+  ['1.3', '1'],
+  ['2', '1'],
+  ['3', '2'],
+  ['3.1', '2'],
+  ['4', '3.2'],
+  ['5', '4.2'],
+  ['5.1', '6'],
+  ['9.1', '9.3'],
+  ['10.1', '10.3'],
+  ['11.1', '11.3'],
+  ['12.1', '12.2'],
+  ['13.1', '13.4'],
+  ['14.1', '14.5'],
+]);
+
 /**
  * @param {string} targetBrowser
  * @param {string} sourceVersion
@@ -33,6 +59,21 @@ export const getMatchingBrowserVersion = (
   }
   /* c8 ignore stop */
 
+  if (targetBrowser === 'safari_ios') {
+    // The mapping between Safari macOS and iOS releases is complicated and
+    // cannot be entirely derived from the WebKit versions. After Safari 15
+    // the versions have been the same, so map earlier versions manually
+    // and then assume if the versions are identical it's also a match.
+    const v = matchingSafariVersions.get(sourceVersion);
+    if (v) {
+      return v;
+    }
+    if (sourceVersion in browserData.releases) {
+      return sourceVersion;
+    }
+    throw new Error(`Cannot find iOS version matching Safari ${sourceVersion}`);
+  }
+
   const releaseKeys = Object.keys(browserData.releases);
   releaseKeys.sort(compareVersions);