refactor: update CrossFileMatch to use Sets for duplicates and optimi…

…ze hash grouping logic
solid-illiaaihistov · Aug 27, 2026 · Aug 21, 2026 · Aug 21, 2026 · Aug 21, 2026 · Aug 26, 2026
commit b3e29586caa7ddd20281ead5bf0bf54a3460d030
diff --git a/lib/src/lints/avoid_duplicate_code/models/cross_file_match.dart b/lib/src/lints/avoid_duplicate_code/models/cross_file_match.dart
@@ -1,3 +1,4 @@
+import 'package:collection/collection.dart';
 import 'package:solid_lints/src/lints/avoid_duplicate_code/models/duplicate_location.dart';
 import 'package:solid_lints/src/lints/avoid_duplicate_code/models/hash_entry.dart';
 
@@ -6,9 +7,9 @@ class CrossFileMatch {
   /// The hash entry in the current file.
   final HashEntry currentEntry;
 
-  /// The list of locations in other files where a duplicate of this entry
+  /// The set of locations in other files where a duplicate of this entry
   /// exists.
-  final List<DuplicateLocation> duplicates;
+  final Set<DuplicateLocation> duplicates;
 
   /// Creates a new [CrossFileMatch].
   const CrossFileMatch({
@@ -21,14 +22,8 @@ class CrossFileMatch {
 extension CrossFileMatchIterableExtension on Iterable<CrossFileMatch> {
   /// Converts this iterable of cross-file matches to a map of unique duplicates
   /// grouped by entry hash.
-  Map<int, List<DuplicateLocation>> toDuplicatesByHash() {
-    final result = <int, List<DuplicateLocation>>{};
-
-    for (final CrossFileMatch(:currentEntry, :duplicates) in this) {
-      final locations = result[currentEntry.hash] ??= [];
-      locations.addAll(duplicates.where((loc) => !locations.contains(loc)));
-    }
-
-    return result;
-  }
+  Map<int, Set<DuplicateLocation>> toDuplicatesByHash() => groupFoldBy(
+    (match) => match.currentEntry.hash,
+    (previous, match) => {...?previous, ...match.duplicates},
+  );
 }
diff --git a/lib/src/lints/avoid_duplicate_code/reporters/avoid_duplicate_code_reporter.dart b/lib/src/lints/avoid_duplicate_code/reporters/avoid_duplicate_code_reporter.dart
@@ -29,7 +29,7 @@ class AvoidDuplicateCodeReporter {
   void report({
     required String filePath,
     required List<DuplicateReportContext> contexts,
-    required Map<int, List<DuplicateLocation>> crossFileDuplicatesByHash,
+    required Map<int, Set<DuplicateLocation>> crossFileDuplicatesByHash,
   }) {
     final hashGroups = groupBy(contexts, (c) => c.entry.hash);
     final suppressedRanges = <(int, int)>[];
@@ -51,7 +51,7 @@ class AvoidDuplicateCodeReporter {
                 !suppressedRanges.anyContainsStrictly(c.entry.range),
           )
           .toList();
-      final externalPartners = crossFileDuplicatesByHash[hash] ?? const [];
+      final externalPartners = crossFileDuplicatesByHash[hash] ?? const {};
 
       if (internalPartners.isEmpty && externalPartners.isEmpty) continue;
 
@@ -71,7 +71,7 @@ class AvoidDuplicateCodeReporter {
     required String filePath,
     required DuplicateReportContext target,
     required List<DuplicateReportContext> internalPartners,
-    required List<DuplicateLocation> externalPartners,
+    required Set<DuplicateLocation> externalPartners,
   }) {
     final currentExactHash = target.entry.exactHash;
     final internalEntries = internalPartners.map((p) => p.entry).toList();
@@ -114,7 +114,7 @@ class AvoidDuplicateCodeReporter {
   }
 
   Iterable<List<LiteralInfo>> _loadExternalLiterals(
-    List<DuplicateLocation> locations,
+    Set<DuplicateLocation> locations,
   ) => locations
       .map(_literalsAnalyzer.loadExternalLiterals)
       .nonNulls
@@ -135,7 +135,7 @@ class AvoidDuplicateCodeReporter {
   List<DiagnosticMessage> _buildContextMessages({
     required String currentFilePath,
     required int currentExactHash,
-    required List<DuplicateLocation> externalPartners,
+    required Set<DuplicateLocation> externalPartners,
     required Iterable<HashEntry> internalPartners,
   }) {
     String messageFor(int exactHash) => exactHash == currentExactHash

diff --git a/lib/src/lints/avoid_duplicate_code/services/global_hash_registry.dart b/lib/src/lints/avoid_duplicate_code/services/global_hash_registry.dart
@@ -230,7 +230,7 @@ class GlobalHashRegistry {
     final fileStatusCache = <String, bool>{};
 
     for (final entry in currentEntries) {
-      final duplicates = <DuplicateLocation>[];
+      final duplicates = <DuplicateLocation>{};
       final locations = _hashToLocations[entry.hash];
 
       if (locations == null) continue;

diff --git a/lib/src/lints/avoid_duplicate_code/visitors/avoid_duplicate_code_visitor.dart b/lib/src/lints/avoid_duplicate_code/visitors/avoid_duplicate_code_visitor.dart
@@ -208,7 +208,7 @@ class AvoidDuplicateCodeVisitor extends RecursiveAstVisitor<void> {
   bool _isFileExcluded(String path) =>
       _analysisOptionsLoader?.isFileExcludedForFile(path) ?? false;
 
-  Map<int, List<DuplicateLocation>> _findAndSaveCrossFileMatches(
+  Map<int, Set<DuplicateLocation>> _findAndSaveCrossFileMatches(
     String filePath,
     List<HashEntry> hashEntries,
     String packageRoot,

diff --git a/test/src/lints/avoid_duplicate_code/global_hash_registry_test.dart b/test/src/lints/avoid_duplicate_code/global_hash_registry_test.dart
@@ -346,8 +346,10 @@ void main() {
         final expectedPathB = p.normalize(
           p.join(io.Directory.current.path, 'file_b.dart'),
         );
-        expect(matches.first.duplicates[0].filePath, equals(expectedPathA));
-        expect(matches.first.duplicates[1].filePath, equals(expectedPathB));
+        expect(
+          matches.first.duplicates.map((d) => d.filePath),
+          containsAll([expectedPathA, expectedPathB]),
+        );
       });
 
       test('findCrossFileMatches processes multiple candidates correctly', () {

diff --git a/test/src/lints/avoid_duplicate_code/models/cross_file_match_test.dart b/test/src/lints/avoid_duplicate_code/models/cross_file_match_test.dart
@@ -6,63 +6,61 @@ import 'package:test/test.dart';
 void main() {
   group('CrossFileMatchIterableExtension', () {
     test('toDuplicatesByHash groups matches by entry hash', () {
+      final locA = DuplicateLocation(
+        filePath: 'lib/a.dart',
+        entry: _TestFactory.entry(hash: 100, offset: 10),
+      );
+      final locB = DuplicateLocation(
+        filePath: 'lib/b.dart',
+        entry: _TestFactory.entry(hash: 200, offset: 20),
+      );
       final match1 = CrossFileMatch(
         currentEntry: _TestFactory.entry(hash: 100, offset: 0),
-        duplicates: [
-          DuplicateLocation(
-            filePath: 'lib/a.dart',
-            entry: _TestFactory.entry(hash: 100, offset: 10),
-          ),
-        ],
+        duplicates: {locA},
       );
       final match2 = CrossFileMatch(
         currentEntry: _TestFactory.entry(hash: 200, offset: 50),
-        duplicates: [
-          DuplicateLocation(
-            filePath: 'lib/b.dart',
-            entry: _TestFactory.entry(hash: 200, offset: 20),
-          ),
-        ],
+        duplicates: {locB},
       );
 
       final result = [match1, match2].toDuplicatesByHash();
 
-      expect(result.keys, containsAll([100, 200]));
-      expect(result[100], hasLength(1));
-      expect(result[100]!.first.filePath, 'lib/a.dart');
-      expect(result[200], hasLength(1));
-      expect(result[200]!.first.filePath, 'lib/b.dart');
+      expect(
+        result,
+        equals({
+          100: {locA},
+          200: {locB},
+        }),
+      );
     });
 
     test(
       'toDuplicatesByHash aggregates duplicates when matches share same hash',
       () {
+        final locA = DuplicateLocation(
+          filePath: 'lib/a.dart',
+          entry: _TestFactory.entry(hash: 100, offset: 10),
+        );
+        final locB = DuplicateLocation(
+          filePath: 'lib/b.dart',
+          entry: _TestFactory.entry(hash: 100, offset: 20),
+        );
         final match1 = CrossFileMatch(
           currentEntry: _TestFactory.entry(hash: 100, offset: 0),
-          duplicates: [
-            DuplicateLocation(
-              filePath: 'lib/a.dart',
-              entry: _TestFactory.entry(hash: 100, offset: 10),
-            ),
-          ],
+          duplicates: {locA},
         );
         final match2 = CrossFileMatch(
           currentEntry: _TestFactory.entry(hash: 100, offset: 100),
-          duplicates: [
-            DuplicateLocation(
-              filePath: 'lib/b.dart',
-              entry: _TestFactory.entry(hash: 100, offset: 20),
-            ),
-          ],
+          duplicates: {locB},
         );
 
         final result = [match1, match2].toDuplicatesByHash();
 
-        expect(result.keys, equals([100]));
-        expect(result[100], hasLength(2));
         expect(
-          result[100]!.map((d) => d.filePath),
-          containsAll(['lib/a.dart', 'lib/b.dart']),
+          result,
+          equals({
+            100: {locA, locB},
+          }),
         );
       },
     );
@@ -74,18 +72,21 @@ void main() {
       );
       final match1 = CrossFileMatch(
         currentEntry: _TestFactory.entry(hash: 100, offset: 0),
-        duplicates: [loc],
+        duplicates: {loc},
       );
       final match2 = CrossFileMatch(
         currentEntry: _TestFactory.entry(hash: 100, offset: 50),
-        duplicates: [loc],
+        duplicates: {loc},
       );
 
       final result = [match1, match2].toDuplicatesByHash();
 
-      expect(result.keys, equals([100]));
-      expect(result[100], hasLength(1));
-      expect(result[100]!.first.filePath, 'lib/a.dart');
+      expect(
+        result,
+        equals({
+          100: {loc},
+        }),
+      );
     });
   });
 }