[coverage] Expose filterIgnored function (#2123)

liamappelbe · web-flow · commit 1500539bc290 · 2025-07-09T09:53:37.000+10:00
diff --git a/pkgs/coverage/CHANGELOG.md b/pkgs/coverage/CHANGELOG.md
@@ -1,3 +1,9 @@
+## 1.15.0
+
+- Expose `filterIgnored` function, which filters the coverage data according to
+  `// coverage:ignore-...` comments. Previously this filtering functionality
+  was only available when loading coverage data from json using `parseJson` etc.
+
 ## 1.14.1
 
 - Remove dependency on `package:pubspec_parse`.
diff --git a/pkgs/coverage/lib/src/hitmap.dart b/pkgs/coverage/lib/src/hitmap.dart
@@ -59,8 +59,6 @@ class HitMap {
     required Map<String, List<List<int>>?> ignoredLinesInFilesCache,
     required Resolver resolver,
   }) {
-    final loader = Loader();
-
     // Map of source file to map of line to hit count for that line.
     final globalHitMap = <String, HitMap>{};
 
@@ -71,66 +69,6 @@ class HitMap {
         continue;
       }
 
-      var ignoredLinesList = <List<int>>[];
-
-      if (checkIgnoredLines) {
-        if (ignoredLinesInFilesCache.containsKey(source)) {
-          final cacheHit = ignoredLinesInFilesCache[source];
-          if (cacheHit == null) {
-            // Null-entry indicates that the whole file was ignored.
-            continue;
-          }
-          ignoredLinesList = cacheHit;
-        } else {
-          final path = resolver.resolve(source);
-          if (path != null) {
-            final lines = loader.loadSync(path) ?? [];
-            ignoredLinesList = getIgnoredLines(path, lines);
-
-            // Ignore the whole file.
-            if (ignoredLinesList.length == 1 &&
-                ignoredLinesList[0][0] == 0 &&
-                ignoredLinesList[0][1] == lines.length) {
-              // Null-entry indicates that the whole file was ignored.
-              ignoredLinesInFilesCache[source] = null;
-              continue;
-            }
-            ignoredLinesInFilesCache[source] = ignoredLinesList;
-          } else {
-            // Couldn't resolve source. Allow cache to answer next time
-            // anyway.
-            ignoredLinesInFilesCache[source] = ignoredLinesList;
-          }
-        }
-      }
-
-      // Move to the first ignore range.
-      final ignoredLines = ignoredLinesList.iterator;
-      var hasCurrent = ignoredLines.moveNext();
-
-      bool shouldIgnoreLine(Iterator<List<int>> ignoredRanges, int line) {
-        if (!hasCurrent || ignoredRanges.current.isEmpty) {
-          return false;
-        }
-
-        if (line < ignoredRanges.current[0]) return false;
-
-        while (hasCurrent &&
-            ignoredRanges.current.isNotEmpty &&
-            ignoredRanges.current[1] < line) {
-          hasCurrent = ignoredRanges.moveNext();
-        }
-
-        if (hasCurrent &&
-            ignoredRanges.current.isNotEmpty &&
-            ignoredRanges.current[0] <= line &&
-            line <= ignoredRanges.current[1]) {
-          return true;
-        }
-
-        return false;
-      }
-
       void addToMap(Map<int, int> map, int line, int count) {
         final oldCount = map.putIfAbsent(line, () => 0);
         map[line] = count + oldCount;
@@ -147,17 +85,13 @@ class HitMap {
           final k = hits[i];
           if (k is int) {
             // Single line.
-            if (shouldIgnoreLine(ignoredLines, k)) continue;
-
             addToMap(hitMap, k, hits[i + 1] as int);
           } else if (k is String) {
             // Linerange. We expand line ranges to actual lines at this point.
             final splitPos = k.indexOf('-');
             final start = int.parse(k.substring(0, splitPos));
             final end = int.parse(k.substring(splitPos + 1));
             for (var j = start; j <= end; j++) {
-              if (shouldIgnoreLine(ignoredLines, j)) continue;
-
               addToMap(hitMap, j, hits[i + 1] as int);
             }
           } else {
@@ -185,7 +119,12 @@ class HitMap {
         fillHitMap(e['branchHits'] as List, sourceHitMap.branchHits!);
       }
     }
-    return globalHitMap;
+    return checkIgnoredLines
+        ? globalHitMap.filterIgnored(
+            ignoredLinesInFilesCache: ignoredLinesInFilesCache,
+            resolver: resolver,
+          )
+        : globalHitMap;
   }
 
   /// Creates a single hitmap from a raw json object.
@@ -268,6 +207,39 @@ extension FileHitMaps on Map<String, HitMap> {
       }
     });
   }
+
+  /// Filters out lines that are ignored by ignore comments.
+  Map<String, HitMap> filterIgnored({
+    required Map<String, List<List<int>>?> ignoredLinesInFilesCache,
+    required Resolver resolver,
+  }) {
+    final loader = Loader();
+    final newHitMaps = <String, HitMap>{};
+    for (final MapEntry(key: source, value: hitMap) in entries) {
+      final ignoredLinesList = ignoredLinesInFilesCache.putIfAbsent(source, () {
+        final path = resolver.resolve(source);
+        if (path == null) return <List<int>>[];
+        return getIgnoredLines(path, loader.loadSync(path));
+      });
+      // Null here means that the whole file is ignored.
+      if (ignoredLinesList == null) continue;
+
+      Map<int, int>? filterHits(Map<int, int>? hits) => hits == null
+          ? null
+          : {
+              for (final MapEntry(key: line, value: count) in hits.entries)
+                if (!ignoredLinesList.ignoredContains(line)) line: count,
+            };
+
+      newHitMaps[source] = HitMap(
+        filterHits(hitMap.lineHits),
+        filterHits(hitMap.funcHits),
+        hitMap.funcNames,
+        filterHits(hitMap.branchHits),
+      );
+    }
+    return newHitMaps;
+  }
 }
 
 /// Class containing information about a coverage hit.
diff --git a/pkgs/coverage/lib/src/util.dart b/pkgs/coverage/lib/src/util.dart
@@ -59,16 +59,16 @@ Uri? extractVMServiceUri(String str) {
   return null;
 }
 
-final muliLineIgnoreStart = RegExp(r'//\s*coverage:ignore-start[\w\d\s]*$');
-final muliLineIgnoreEnd = RegExp(r'//\s*coverage:ignore-end[\w\d\s]*$');
+final multiLineIgnoreStart = RegExp(r'//\s*coverage:ignore-start[\w\d\s]*$');
+final multiLineIgnoreEnd = RegExp(r'//\s*coverage:ignore-end[\w\d\s]*$');
 final singleLineIgnore = RegExp(r'//\s*coverage:ignore-line[\w\d\s]*$');
 final ignoreFile = RegExp(r'//\s*coverage:ignore-file[\w\d\s]*$');
 
-/// Return list containing inclusive range of lines to be ignored by coverage.
+/// Return list containing inclusive ranges of lines to be ignored by coverage.
 /// If there is a error in balancing the statements it will throw a
 /// [FormatException],
 /// unless `coverage:ignore-file` is found.
-/// Return [0, lines.length] if the whole file is ignored.
+/// Return null if the whole file is ignored.
 ///
 /// ```
 /// 1.  final str = ''; // coverage:ignore-line
@@ -86,42 +86,39 @@ final ignoreFile = RegExp(r'//\s*coverage:ignore-file[\w\d\s]*$');
 /// ]
 /// ```
 ///
-List<List<int>> getIgnoredLines(String filePath, List<String>? lines) {
+/// The returned ranges are in sorted order, and never overlap.
+List<List<int>>? getIgnoredLines(String filePath, List<String>? lines) {
   final ignoredLines = <List<int>>[];
   if (lines == null) return ignoredLines;
 
-  final allLines = [
-    [0, lines.length]
-  ];
-
   FormatException? err;
   var i = 0;
   while (i < lines.length) {
-    if (lines[i].contains(ignoreFile)) return allLines;
+    if (lines[i].contains(ignoreFile)) return null;
 
-    if (lines[i].contains(muliLineIgnoreEnd)) {
+    if (lines[i].contains(multiLineIgnoreEnd)) {
       err ??= FormatException(
         'unmatched coverage:ignore-end found at $filePath:${i + 1}',
       );
     }
 
     if (lines[i].contains(singleLineIgnore)) ignoredLines.add([i + 1, i + 1]);
 
-    if (lines[i].contains(muliLineIgnoreStart)) {
+    if (lines[i].contains(multiLineIgnoreStart)) {
       final start = i;
       var isUnmatched = true;
       ++i;
       while (i < lines.length) {
-        if (lines[i].contains(ignoreFile)) return allLines;
-        if (lines[i].contains(muliLineIgnoreStart)) {
+        if (lines[i].contains(ignoreFile)) return null;
+        if (lines[i].contains(multiLineIgnoreStart)) {
           err ??= FormatException(
             'coverage:ignore-start found at $filePath:${i + 1}'
             ' before previous coverage:ignore-start ended',
           );
           break;
         }
 
-        if (lines[i].contains(muliLineIgnoreEnd)) {
+        if (lines[i].contains(multiLineIgnoreEnd)) {
           ignoredLines.add([start + 1, i + 1]);
           isUnmatched = false;
           break;
@@ -146,6 +143,26 @@ List<List<int>> getIgnoredLines(String filePath, List<String>? lines) {
   throw err;
 }
 
+extension IgnoredLinesContains on List<List<int>> {
+  /// Returns whether this list of line ranges contains the given line.
+  bool ignoredContains(int line) {
+    if (length == 0 || this[0][0] > line) return false;
+
+    // Binary search for the range with the largest start value that is <= line.
+    var lo = 0;
+    var hi = length;
+    while (lo < hi - 1) {
+      final mid = lo + (hi - lo) ~/ 2;
+      if (this[mid][0] <= line) {
+        lo = mid;
+      } else {
+        hi = mid;
+      }
+    }
+    return this[lo][1] >= line;
+  }
+}
+
 extension StandardOutExtension on Stream<List<int>> {
   Stream<String> lines() =>
       transform(const SystemEncoding().decoder).transform(const LineSplitter());
diff --git a/pkgs/coverage/pubspec.yaml b/pkgs/coverage/pubspec.yaml
@@ -1,5 +1,5 @@
 name: coverage
-version: 1.14.1
+version: 1.15.0
 description: Coverage data manipulation and formatting
 repository: https://github.com/dart-lang/tools/tree/main/pkgs/coverage
 issue_tracker: https://github.com/dart-lang/tools/issues?q=is%3Aissue+is%3Aopen+label%3Apackage%3Acoverage
diff --git a/pkgs/coverage/test/filter_ignored_test.dart b/pkgs/coverage/test/filter_ignored_test.dart
@@ -0,0 +1,103 @@
+// Copyright (c) 2025, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+import 'dart:io';
+
+import 'package:coverage/coverage.dart' show Resolver;
+import 'package:coverage/src/hitmap.dart';
+import 'package:test/test.dart';
+
+String fileUri(String relativePath) =>
+    Uri.file(File(relativePath).absolute.path).toString();
+
+void main() {
+  test('filter ignored', () async {
+    // The ignored lines come from the comments in the test dart files. But the
+    // hitmaps are fake, and don't have to correspond to real coverage data.
+    final hitmaps = {
+      fileUri('nonexistent_file.dart'): HitMap(
+        {1: 1, 2: 2, 3: 3},
+        {1: 1, 2: 2, 3: 3},
+        {1: 'abc', 2: 'def'},
+        {1: 1, 2: 2, 3: 3},
+      ),
+      fileUri('another_nonexistent_file.dart'): HitMap(
+        {1: 1, 2: 2, 3: 3},
+      ),
+      fileUri('test/test_files/test_app.dart'): HitMap(
+        {1: 1, 2: 2, 3: 3},
+        {1: 1, 2: 2, 3: 3},
+        {1: 'abc', 2: 'def'},
+        {1: 1, 2: 2, 3: 3},
+      ),
+      fileUri('test/test_files/test_app_isolate.dart'): HitMap(
+        {for (var i = 50; i < 100; ++i) i: i},
+        {for (var i = 50; i < 100; ++i) i: i},
+        {for (var i = 50; i < 100; ++i) i: '$i'},
+        {for (var i = 50; i < 100; ++i) i: i},
+      ),
+    };
+
+    // Lines ignored in test/test_files/test_app_isolate.dart.
+    const ignores = [
+      52,
+      54,
+      55,
+      56,
+      57,
+      58,
+      63,
+      64,
+      65,
+      66,
+      67,
+      68,
+      69,
+      70,
+      71,
+      72,
+      73,
+    ];
+
+    final expected = {
+      fileUri('nonexistent_file.dart'): HitMap(
+        {1: 1, 2: 2, 3: 3},
+        {1: 1, 2: 2, 3: 3},
+        {1: 'abc', 2: 'def'},
+        {1: 1, 2: 2, 3: 3},
+      ),
+      fileUri('another_nonexistent_file.dart'): HitMap(
+        {1: 1, 2: 2, 3: 3},
+      ),
+      fileUri('test/test_files/test_app_isolate.dart'): HitMap(
+        {
+          for (var i = 50; i < 100; ++i)
+            if (!ignores.contains(i)) i: i
+        },
+        {
+          for (var i = 50; i < 100; ++i)
+            if (!ignores.contains(i)) i: i
+        },
+        {for (var i = 50; i < 100; ++i) i: '$i'},
+        {
+          for (var i = 50; i < 100; ++i)
+            if (!ignores.contains(i)) i: i
+        },
+      ),
+    };
+
+    final resolver = await Resolver.create(packagePath: '.');
+
+    final actual =
+        hitmaps.filterIgnored(ignoredLinesInFilesCache: {}, resolver: resolver);
+
+    expect(actual.keys.toList(), expected.keys.toList());
+    for (final source in expected.keys) {
+      expect(actual[source]!.lineHits, expected[source]!.lineHits);
+      expect(actual[source]!.funcHits, expected[source]!.funcHits);
+      expect(actual[source]!.funcNames, expected[source]!.funcNames);
+      expect(actual[source]!.branchHits, expected[source]!.branchHits);
+    }
+  });
+}
diff --git a/pkgs/coverage/test/util_test.dart b/pkgs/coverage/test/util_test.dart
