From ddca3181d18541db4cc281d671850c3b64c05c23 Mon Sep 17 00:00:00 2001
From: Ann Mossman <233583+mossmana@users.noreply.github.com>
Date: Tue, 17 Dec 2024 16:58:26 -0800
Subject: [PATCH] skip processing files if the license already exists

---
 tool/lib/license_utils.dart       | 24 ++++++++++++++--
 tool/test/license_utils_test.dart | 48 ++++++++++++++-----------------
 2 files changed, 42 insertions(+), 30 deletions(-)

diff --git a/tool/lib/license_utils.dart b/tool/lib/license_utils.dart
index cf2ad3ac20b..c63338fe906 100644
--- a/tool/lib/license_utils.dart
+++ b/tool/lib/license_utils.dart
@@ -303,19 +303,37 @@ class LicenseHeader {
           // skip if add index doesn't exist for extension
           continue;
         }
+        final fileLength = file.lengthSync();
+        const bufferSize = 20;
         final replacementLicenseText = config.addLicenses[addIndex];
+        final byteCount = min(
+          bufferSize + replacementLicenseText.length,
+          fileLength,
+        );
+        var replacementInfo = await getReplacementInfo(
+          file: file,
+          existingLicenseText: replacementLicenseText,
+          replacementLicenseText: replacementLicenseText,
+          byteCount: byteCount as int,
+        );
+        if (replacementInfo.existingHeader.isNotEmpty &&
+            replacementInfo.replacementHeader.isNotEmpty &&
+            replacementInfo.existingHeader ==
+                replacementInfo.replacementHeader) {
+          // Do nothing if the replacement header is the same as the
+          // existing header
+          continue;
+        }
         final removeIndices = config.getRemoveIndicesForExtension(extension);
         for (final removeIndex in removeIndices) {
           final existingLicenseText = config.removeLicenses[removeIndex];
-          final fileLength = file.lengthSync();
-          const bufferSize = 20;
           // Assume that the license text will be near the start of the file,
           // but add in some buffer.
           final byteCount = min(
             bufferSize + existingLicenseText.length,
             fileLength,
           );
-          final replacementInfo = await getReplacementInfo(
+          replacementInfo = await getReplacementInfo(
             file: file,
             existingLicenseText: existingLicenseText,
             replacementLicenseText: replacementLicenseText,
diff --git a/tool/test/license_utils_test.dart b/tool/test/license_utils_test.dart
index 8eb0e731034..a149cade759 100644
--- a/tool/test/license_utils_test.dart
+++ b/tool/test/license_utils_test.dart
@@ -52,7 +52,8 @@ late File testFile9;
 late File testFile10;
 late File excludeFile1;
 late File excludeFile2;
-late File skippedFile;
+late File skipFile;
+late File doNothingFile;
 
 void main() {
   group('config file tests', () {
@@ -257,27 +258,6 @@ text that should be added to the file. */''',
       }
     });
 
-    test('update skipped if license text not found', () async {
-      var errorMessage = '';
-      final header = LicenseHeader();
-      try {
-        await header.getReplacementInfo(
-          file: testFile9,
-          existingLicenseText: 'test',
-          replacementLicenseText: 'test',
-          byteCount: 50,
-        );
-      } on StateError catch (e) {
-        errorMessage = e.toString();
-      }
-      expect(
-        errorMessage,
-        equals(
-          'Bad state: License header expected in ${testFile9.path}, but not found!',
-        ),
-      );
-    });
-
     test("update skipped if file can't be read", () async {
       var errorMessage = '';
       final header = LicenseHeader();
@@ -363,7 +343,7 @@ text that should be added to the file. */''',
 
       final includedPaths = results.includedPaths;
       expect(includedPaths, isNotNull);
-      expect(includedPaths.length, equals(8));
+      expect(includedPaths.length, equals(9));
       // Order is not guaranteed
       expect(includedPaths.contains(testFile1.path), true);
       expect(contentsBeforeUpdate, isNot(equals(contentsAfterUpdate)));
@@ -373,7 +353,8 @@ text that should be added to the file. */''',
       expect(includedPaths.contains(testFile8.path), true);
       expect(includedPaths.contains(testFile9.path), true);
       expect(includedPaths.contains(testFile10.path), true);
-      expect(includedPaths.contains(skippedFile.path), true);
+      expect(includedPaths.contains(skipFile.path), true);
+      expect(includedPaths.contains(doNothingFile.path), true);
 
       final updatedPaths = results.updatedPaths;
       expect(updatedPaths, isNotNull);
@@ -386,7 +367,8 @@ text that should be added to the file. */''',
       expect(updatedPaths.contains(testFile8.path), true);
       expect(updatedPaths.contains(testFile9.path), true);
       expect(updatedPaths.contains(testFile10.path), true);
-      expect(updatedPaths.contains(skippedFile.path), false);
+      expect(updatedPaths.contains(skipFile.path), false);
+      expect(updatedPaths.contains(doNothingFile.path), false);
     });
 
     test('license headers bulk update can be dry run', () async {
@@ -544,6 +526,10 @@ update_paths:
     ext2:
       remove:
         - 2
+      add: 1
+    ext3:
+      remove:
+        - 3
       add: 1''';
 
   configFile.writeAsStringSync(contents, flush: true);
@@ -588,9 +574,17 @@ Future<void> _setupTestDirectoryStructure() async {
     ..createSync(recursive: true);
   testFile2.writeAsStringSync(licenseText3 + extraText, flush: true);
 
-  skippedFile = File(p.join(repoRoot.path, 'test.skip'))
+  final licenseText = '''
+# This is other 2001 multiline license
+# text that should be added to the file.
+''';
+  doNothingFile = File(p.join(repoRoot.path, 'doNothingFile.ext3'))
+    ..createSync(recursive: true);
+  doNothingFile.writeAsStringSync(licenseText + extraText, flush: true);
+
+  skipFile = File(p.join(repoRoot.path, 'test.skip'))
     ..createSync(recursive: true);
-  skippedFile.writeAsStringSync(extraText, flush: true);
+  skipFile.writeAsStringSync(extraText, flush: true);
 
   // Setup /repo_root/.hidden directory structure
   Directory(p.join(repoRoot.path, '.hidden')).createSync(recursive: true);