[flutter_plugin_tools] Fix license-check on Windows (flutter#4425)

Author: stuartmorgan-g

script/tool/CHANGELOG.md

@@ -13,6 +13,7 @@
 - `license-check` now validates Kotlin files.
 - `pubspec-check` now checks that the description is of the pub-recommended
   length.
+- Fix `license-check` when run on Windows with line ending conversion enabled.
 
 ## 0.7.1
 

script/tool/lib/src/license_check_command.dart

@@ -206,7 +206,10 @@ class LicenseCheckCommand extends PluginCommand {
 
     for (final File file in codeFiles) {
       print('Checking ${file.path}');
-      final String content = await file.readAsString();
+      // On Windows, git may auto-convert line endings on checkout; this should
+      // still pass since they will be converted back on commit.
+      final String content =
+          (await file.readAsString()).replaceAll('\r\n', '\n');
 
       final String firstParyLicense =
           firstPartyLicenseBlockByExtension[p.extension(file.path)] ??
@@ -244,7 +247,10 @@ class LicenseCheckCommand extends PluginCommand {
 
     for (final File file in files) {
       print('Checking ${file.path}');
-      if (!file.readAsStringSync().contains(_fullBsdLicenseText)) {
+      // On Windows, git may auto-convert line endings on checkout; this should
+      // still pass since they will be converted back on commit.
+      final String contents = file.readAsStringSync().replaceAll('\r\n', '\n');
+      if (!contents.contains(_fullBsdLicenseText)) {
         incorrectLicenseFiles.add(file);
       }
     }

script/tool/test/license_check_command_test.dart

@@ -48,12 +48,14 @@ void main() {
         'Use of this source code is governed by a BSD-style license that can be',
         'found in the LICENSE file.',
       ],
+      bool useCrlf = false,
     }) {
       final List<String> lines = <String>['$prefix$comment$copyright'];
       for (final String line in license) {
         lines.add('$comment$line');
       }
-      file.writeAsStringSync(lines.join('\n') + suffix + '\n');
+      final String newline = useCrlf ? '\r\n' : '\n';
+      file.writeAsStringSync(lines.join(newline) + suffix + newline);
     }
 
     test('looks at only expected extensions', () async {
@@ -140,6 +142,23 @@ void main() {
           ]));
     });
 
+    test('passes correct license blocks on Windows', () async {
+      final File checked = root.childFile('checked.cc');
+      checked.createSync();
+      _writeLicense(checked, useCrlf: true);
+
+      final List<String> output =
+          await runCapturingPrint(runner, <String>['license-check']);
+
+      // Sanity check that the test did actually check a file.
+      expect(
+          output,
+          containsAllInOrder(<Matcher>[
+            contains('Checking checked.cc'),
+            contains('All files passed validation!'),
+          ]));
+    });
+
     test('handles the comment styles for all supported languages', () async {
       final File fileA = root.childFile('file_a.cc');
       fileA.createSync();
@@ -406,6 +425,24 @@ void main() {
           ]));
     });
 
+    test('passes correct LICENSE files on Windows', () async {
+      final File license = root.childFile('LICENSE');
+      license.createSync();
+      license
+          .writeAsStringSync(_correctLicenseFileText.replaceAll('\n', '\r\n'));
+
+      final List<String> output =
+          await runCapturingPrint(runner, <String>['license-check']);
+
+      // Sanity check that the test did actually check the file.
+      expect(
+          output,
+          containsAllInOrder(<Matcher>[
+            contains('Checking LICENSE'),
+            contains('All files passed validation!'),
+          ]));
+    });
+
     test('fails if any first-party LICENSE files are incorrectly formatted',
         () async {
       final File license = root.childFile('LICENSE');