Check hashes on change

.github/workflows/intl4x_artifacts.yml

@@ -4,9 +4,15 @@ permissions:
   contents: write
 
 on:
+  pull_request:
+    branches: [ main ]
+    paths:
+      - pkgs/intl4x/hook/hashes.dart
   push:
     tags:
       - 'intl4x-icu*'
+  schedule:
+    - cron: '0 0 * * 0' # weekly
   workflow_dispatch:
 
 jobs:
@@ -138,6 +144,16 @@ jobs:
       with:
         name: dart-${{matrix.os}}-libs
         path: submodules/icu4x/bin
+
+  check_hashes:
+    needs: dart-libs
+    if: github.event_name == 'pull_request'
+    runs-on: ubuntu-latest
+    steps:
+      - run: |
+          cd pkgs/intl4x
+          dart --enable-experiment=native-assets run tool/generate_hashes.dart local ../../submodules/icu4x/bin/
+          git diff --name-only --exit-code
   
   release:
     needs: dart-libs

pkgs/intl4x/tool/generate_hashes.dart

@@ -5,25 +5,29 @@ import 'package:native_assets_cli/native_assets_cli.dart';
 
 import '../hook/build.dart';
 
+final httpClient = HttpClient();
+
 Future<void> main(List<String> args) async {
+  final mode = args.firstOrNull;
+  String folder() => args[1];
+
   print('Checking hashes for $version');
   final fileHashes = <(OS, Architecture), String>{};
   final dynamicLibrary = File.fromUri(Directory.systemTemp.uri.resolve('lib'));
   await dynamicLibrary.create();
-  final httpClient = HttpClient();
   for (final os in OS.values) {
     for (final architecture in Architecture.values) {
       final target = '${os}_$architecture';
       print('Checking hash for $target');
-      final uri = Uri.parse(
-          'https://github.com/dart-lang/i18n/releases/download/$version/$target');
-      final request = await httpClient.getUrl(uri);
-      final response = await request.close();
-      if (response.statusCode != 200) {
-        print('File not found at $uri');
+      final bool success;
+      if (mode == 'fetch' || mode == null) {
+        success = await _fetchLibrary(target, httpClient, dynamicLibrary);
+      } else if (mode == 'local') {
+        success = await _copyLibrary(target, folder(), dynamicLibrary);
       } else {
-        await response.pipe(dynamicLibrary.openWrite());
-
+        throw UnsupportedError('Mode must be fetch or local');
+      }
+      if (success) {
         final bytes = await dynamicLibrary.readAsBytes();
         final fileHash = sha256.convert(bytes).toString();
         fileHashes[(os, architecture)] = fileHash;
@@ -56,6 +60,34 @@ ${fileHashes.map((key, value) => MapEntry(
 ''');
 }
 
+Future<bool> _copyLibrary(
+  String target,
+  String folder,
+  File dynamicLibrary,
+) async {
+  final fileUri = Directory.current.uri.resolve(folder).resolve(target);
+  final file = File.fromUri(fileUri);
+  if (await file.exists()) {
+    await file.copy(dynamicLibrary.path);
+    return true;
+  }
+  return false;
+}
+
+Future<bool> _fetchLibrary(
+    String target, HttpClient httpClient, File dynamicLibrary) async {
+  final uri = Uri.parse(
+      'https://github.com/dart-lang/i18n/releases/download/$version/$target');
+  final request = await httpClient.getUrl(uri);
+  final response = await request.close();
+  if (response.statusCode != 200) {
+    print('File not found at $uri');
+    return false;
+  }
+  await response.pipe(dynamicLibrary.openWrite());
+  return true;
+}
+
 extension OSExt on OS {
   String get varName => switch (this) {
         OS.linux => 'linux',