crdt_sync_dart: latest stable + exact pins, 100% coverage, CI for both crdt_sync packages

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

.github/workflows/crdt-sync-dart-tests.yml

@@ -0,0 +1,48 @@
+name: crdt_sync_dart tests
+
+on:
+  push:
+    branches: [main]
+    paths: ['crdt_sync_dart/**']
+  pull_request:
+    branches: [main]
+    paths: ['crdt_sync_dart/**']
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    defaults:
+      run:
+        working-directory: crdt_sync_dart
+
+    steps:
+      - uses: actions/checkout@v4
+
+      # Pure Dart, no Flutter dependency -- so setup-dart, not flutter-action.
+      - name: Set up Dart
+        uses: dart-lang/setup-dart@v1
+        with:
+          sdk: stable
+
+      - name: Install dependencies
+        run: dart pub get
+
+      - name: Analyze
+        run: dart analyze --fatal-infos
+
+      - name: Run tests with coverage
+        run: dart test --coverage=coverage
+
+      # Unlike `flutter test --coverage`, `dart test --coverage` emits raw VM
+      # JSON and no lcov. Skipping this step leaves a stale lcov.info on disk
+      # that the gate below happily "passes" -- which is exactly how this
+      # package drifted to 96% while believing it was at 100%.
+      - name: Convert coverage to lcov
+        run: |
+          dart pub global activate coverage
+          dart pub global run coverage:format_coverage \
+            --lcov --in=coverage/test --out=coverage/lcov.info \
+            --report-on=lib --packages=.dart_tool/package_config.json
+
+      - name: Enforce 100% line coverage
+        run: scripts/check_coverage.sh coverage/lcov.info 100

.github/workflows/crdt-sync-flutter-tests.yml

@@ -0,0 +1,36 @@
+name: crdt_sync_flutter tests
+
+on:
+  push:
+    branches: [main]
+    paths: ['crdt_sync_flutter/**', 'crdt_sync_dart/**']
+  pull_request:
+    branches: [main]
+    paths: ['crdt_sync_flutter/**', 'crdt_sync_dart/**']
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    defaults:
+      run:
+        working-directory: crdt_sync_flutter
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Set up Flutter
+        uses: subosito/flutter-action@v2
+        with:
+          channel: stable
+
+      - name: Install dependencies
+        run: flutter pub get
+
+      - name: Analyze
+        run: flutter analyze
+
+      - name: Run tests with coverage
+        run: flutter test --coverage
+
+      - name: Enforce 100% line coverage
+        run: scripts/check_coverage.sh coverage/lcov.info 100

crdt_sync_dart/pubspec.yaml

@@ -9,9 +9,9 @@ environment:
   sdk: ^3.12.2
 
 dependencies:
-  crypto: ^3.0.7
-  http: ^1.6.0
+  crypto: 3.0.7
+  http: 1.6.0
 
 dev_dependencies:
-  lints: ^5.0.0
-  test: ^1.25.0
+  lints: 6.1.0
+  test: 1.31.2

crdt_sync_dart/scripts/check_coverage.sh

@@ -0,0 +1,32 @@
+#!/bin/bash
+
+# ============================================================================
+# Fail if lcov line coverage drops below a threshold.
+#
+# Thin delegate to the shared gate in ~/utils/scripts, which owns the parsing
+# and the threshold comparison. This file used to be a byte-identical copy of
+# that logic; three such copies existed, which is how one package's idea of
+# "covered" drifts from every other package's.
+#
+# Usage: check_coverage.sh <lcov.info> <min_percent>
+# ============================================================================
+
+set -euo pipefail
+
+# Repo-relative, resolved from this script's own location: an absolute
+# /home/... path exits 127 on an Actions runner.
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+readonly SCRIPT_DIR
+readonly SHARED_GATE="${SCRIPT_DIR}/../../scripts/check_coverage.sh"
+
+main() {
+    if [[ ! -f "$SHARED_GATE" ]]; then
+        echo "Error: shared coverage gate not found at $SHARED_GATE" >&2
+        echo "       It lives in the utils repo at scripts/check_coverage.sh." >&2
+        exit 1
+    fi
+
+    exec bash "$SHARED_GATE" "$@"
+}
+
+main "$@"

crdt_sync_dart/test/default_client_and_io_test.dart

@@ -0,0 +1,132 @@
+import 'dart:convert';
+import 'dart:io';
+
+import 'package:crdt_sync/crdt_sync.dart';
+import 'package:crdt_sync/crdt_sync_io.dart';
+import 'package:http/http.dart' as http;
+import 'package:http/testing.dart' as http_testing;
+import 'package:test/test.dart';
+
+/// An in-memory [LogPersistence] so store tests need no filesystem.
+class _MemoryPersistence implements LogPersistence {
+  _MemoryPersistence([this._contents]);
+
+  String? _contents;
+
+  @override
+  Future<String?> read() async => _contents;
+
+  @override
+  Future<void> write(String contents) async => _contents = contents;
+}
+
+void main() {
+  group('default http client', () {
+    // These constructors fall back to a real http.Client() when none is
+    // injected. Nothing here issues a request -- the point is only that the
+    // default branch is taken and the resulting client closes cleanly.
+    test('GitHubClient builds one when none is injected', () {
+      final client = GitHubClient(owner: 'o', repo: 'r', token: 't');
+      addTearDown(client.close);
+      expect(client.owner, 'o');
+      expect(client.repo, 'r');
+    });
+
+    test('GitHubClient.close is safe to call', () {
+      GitHubClient(owner: 'o', repo: 'r', token: 't').close();
+    });
+
+    test('accountFromWrapper builds and closes its own client', () async {
+      // Nothing listens on this port, so the GET throws and the `on Exception`
+      // path returns null -- while the `finally` still closes the client the
+      // function created for itself.
+      final account = await accountFromWrapper(
+        Uri.parse('http://127.0.0.1:1'),
+      );
+      expect(account, isNull);
+    });
+
+    test('accountFromWrapper leaves an injected client open', () async {
+      final mock = http_testing.MockClient(
+        (_) async => http.Response(jsonEncode({}), 404),
+      );
+      expect(await accountFromWrapper(Uri.parse('http://x'), client: mock),
+          isNull);
+      // Still usable: the function must not close a client it did not create.
+      expect((await mock.get(Uri.parse('http://x'))).statusCode, 404);
+    });
+  });
+
+  group('RemoteNotFoundError', () {
+    test('carries its message and is a RemoteSyncError', () {
+      final error = RemoteNotFoundError('nothing synced yet');
+      expect(error, isA<RemoteSyncError>());
+      expect(error.toString(), contains('nothing synced yet'));
+    });
+  });
+
+  group('LogStore tombstone clock tracking', () {
+    test('a loaded tombstone advances the clock past its deletedHlc', () async {
+      // deletedHlc is far ahead of any field clock, so the next local write
+      // can only outrank it if load() fed the tombstone's clock in too.
+      final deletedHlc = Hlc(
+        wallTimeMs: DateTime.utc(2030).millisecondsSinceEpoch,
+        counter: 7,
+        nodeId: 'node-remote',
+      );
+      final log = {
+        'r1': Record(
+          id: 'r1',
+          fields: {
+            'title': ('old', Hlc(wallTimeMs: 1, counter: 0, nodeId: 'node-a')),
+          },
+          deleted: true,
+          deletedHlc: deletedHlc,
+        ),
+      };
+      final store = LogStore(
+        persistence: _MemoryPersistence(logToJson(log)),
+        nodeId: 'node-a',
+      );
+      addTearDown(store.close);
+      await store.load();
+
+      expect(store.nextHlc() > deletedHlc, isTrue);
+    });
+  });
+
+  group('FileLogPersistence', () {
+    late Directory dir;
+
+    setUp(() => dir = Directory.systemTemp.createTempSync('crdt_sync_test'));
+    tearDown(() => dir.deleteSync(recursive: true));
+
+    test('read returns null when the file does not exist', () async {
+      final store = FileLogPersistence(File('${dir.path}/absent.json'));
+      expect(await store.read(), isNull);
+    });
+
+    test('read returns null when the file cannot be read', () async {
+      // A mode-000 file still passes existsSync, so the guard does not fire
+      // and readAsString throws PathAccessException (a FileSystemException).
+      // A directory would NOT work here: File.existsSync() is false for one,
+      // so read() would return early down the guard path instead.
+      final file = File('${dir.path}/unreadable.json')..writeAsStringSync('{}');
+      final chmod = Process.runSync('chmod', ['000', file.path]);
+      expect(chmod.exitCode, 0);
+      addTearDown(() => Process.runSync('chmod', ['644', file.path]));
+
+      expect(await FileLogPersistence(file).read(), isNull);
+    },
+        // root ignores the permission bits, so the exception never fires.
+        skip: Platform.environment['USER'] == 'root'
+            ? 'permission bits do not apply to root'
+            : null);
+
+    test('round-trips what it wrote', () async {
+      final store = FileLogPersistence(File('${dir.path}/log.json'));
+      await store.write('{"hello":"world"}');
+      expect(await store.read(), '{"hello":"world"}');
+    });
+  });
+}

crdt_sync_dart/test/hlc_value_test.dart

@@ -0,0 +1,89 @@
+import 'package:crdt_sync/crdt_sync.dart';
+import 'package:test/test.dart';
+
+Hlc _make(int wallTimeMs, {int counter = 0, String nodeId = 'node-a'}) =>
+    Hlc(wallTimeMs: wallTimeMs, counter: counter, nodeId: nodeId);
+
+void main() {
+  group('comparison operators', () {
+    // compareTo is exercised elsewhere; these cover the four operators that
+    // wrap it, each of which has its own boundary at "exactly equal".
+    test('> is false for equal clocks', () {
+      expect(_make(100) > _make(100), isFalse);
+    });
+
+    test('>= is true for equal clocks', () {
+      expect(_make(100) >= _make(100), isTrue);
+    });
+
+    test('>= is true for a greater clock', () {
+      expect(_make(200) >= _make(100), isTrue);
+    });
+
+    test('>= is false for a lesser clock', () {
+      expect(_make(100) >= _make(200), isFalse);
+    });
+
+    test('< is false for equal clocks', () {
+      expect(_make(100) < _make(100), isFalse);
+    });
+
+    test('< is true for a lesser clock', () {
+      expect(_make(100) < _make(200), isTrue);
+    });
+
+    test('<= is true for equal clocks', () {
+      expect(_make(100) <= _make(100), isTrue);
+    });
+
+    test('<= is false for a greater clock', () {
+      expect(_make(200) <= _make(100), isFalse);
+    });
+  });
+
+  group('equality', () {
+    test('a non-Hlc is never equal', () {
+      // ignore: unrelated_type_equality_checks
+      expect(_make(100) == 'not an hlc', isFalse);
+    });
+
+    test('differing wall time is not equal', () {
+      expect(_make(100), isNot(equals(_make(200))));
+    });
+
+    test('differing counter is not equal', () {
+      expect(_make(100), isNot(equals(_make(100, counter: 1))));
+    });
+
+    test('differing node id is not equal', () {
+      expect(_make(100), isNot(equals(_make(100, nodeId: 'node-b'))));
+    });
+  });
+
+  group('hashCode', () {
+    test('equal clocks hash equally', () {
+      expect(_make(100, counter: 2).hashCode, _make(100, counter: 2).hashCode);
+    });
+
+    test('a differing field changes the hash', () {
+      expect(
+        _make(100, counter: 2).hashCode,
+        isNot(_make(100, counter: 3).hashCode),
+      );
+    });
+
+    test('clocks survive a round trip through a Set', () {
+      final set = {_make(100), _make(100), _make(200)};
+      expect(set, hasLength(2));
+    });
+  });
+
+  group('toString', () {
+    test('names every field so a failed expect is readable', () {
+      expect(
+        _make(100, counter: 2, nodeId: 'node-z').toString(),
+        'Hlc(wallTimeMs: 100, counter: 2, nodeId: node-z)',
+      );
+    });
+  });
+}

crdt_sync_dart/test/record_value_test.dart

@@ -0,0 +1,130 @@
+import 'package:crdt_sync/crdt_sync.dart';
+import 'package:test/test.dart';
+
+Hlc _make(int wallTimeMs, {int counter = 0, String nodeId = 'node-a'}) =>
+    Hlc(wallTimeMs: wallTimeMs, counter: counter, nodeId: nodeId);
+
+Record _record({
+  String id = 'r1',
+  Map<String, Field>? fields,
+  bool deleted = false,
+  Hlc? deletedHlc,
+}) => Record(
+  id: id,
+  fields: fields ?? {'title': ('hello', _make(100))},
+  deleted: deleted,
+  deletedHlc: deletedHlc,
+);
+
+void main() {
+  group('equality', () {
+    test('a non-Record is never equal', () {
+      // ignore: unrelated_type_equality_checks
+      expect(_record() == 'not a record', isFalse);
+    });
+
+    test('same id, fields and tombstone are equal', () {
+      expect(_record(), equals(_record()));
+    });
+
+    test('a differing id is not equal', () {
+      expect(_record(), isNot(equals(_record(id: 'r2'))));
+    });
+
+    test('a differing tombstone is not equal', () {
+      expect(_record(), isNot(equals(_record(deleted: true))));
+    });
+
+    test('a differing deletedHlc is not equal', () {
+      expect(
+        _record(deleted: true, deletedHlc: _make(100)),
+        isNot(equals(_record(deleted: true, deletedHlc: _make(200)))),
+      );
+    });
+  });
+
+  group('field comparison', () {
+    // _fieldsEqual is the one part of == that cannot short-circuit on a
+    // scalar, so each of its exits gets its own case.
+    test('a differing field count is not equal', () {
+      expect(
+        _record(),
+        isNot(
+          equals(
+            _record(
+              fields: {'title': ('hello', _make(100)), 'body': ('x', _make(1))},
+            ),
+          ),
+        ),
+      );
+    });
+
+    test('a differing field value is not equal', () {
+      expect(
+        _record(),
+        isNot(equals(_record(fields: {'title': ('goodbye', _make(100))}))),
+      );
+    });
+
+    test('a differing field clock is not equal', () {
+      expect(
+        _record(),
+        isNot(equals(_record(fields: {'title': ('hello', _make(200))}))),
+      );
+    });
+
+    test('a renamed field of the same count is not equal', () {
+      expect(
+        _record(),
+        isNot(equals(_record(fields: {'heading': ('hello', _make(100))}))),
+      );
+    });
+
+    test('field order does not affect equality', () {
+      final a = _record(
+        fields: {'a': ('1', _make(100)), 'b': ('2', _make(200))},
+      );
+      final b = _record(
+        fields: {'b': ('2', _make(200)), 'a': ('1', _make(100))},
+      );
+      expect(a, equals(b));
+    });
+
+    test('an empty field map equals another empty one', () {
+      expect(_record(fields: {}), equals(_record(fields: {})));
+    });
+  });
+
+  group('hashCode', () {
+    test('equal records hash equally', () {
+      expect(_record().hashCode, _record().hashCode);
+    });
+
+    test('a differing id changes the hash', () {
+      expect(_record().hashCode, isNot(_record(id: 'r2').hashCode));
+    });
+
+    test('hashing does not depend on field order', () {
+      final a = _record(
+        fields: {'a': ('1', _make(100)), 'b': ('2', _make(200))},
+      );
+      final b = _record(
+        fields: {'b': ('2', _make(200)), 'a': ('1', _make(100))},
+      );
+      expect(a.hashCode, b.hashCode);
+    });
+
+    test('records survive a round trip through a Set', () {
+      expect({_record(), _record(), _record(id: 'r2')}, hasLength(2));
+    });
+  });
+
+  group('toString', () {
+    test('names every field so a failed expect is readable', () {
+      expect(
+        _record(fields: {}).toString(),
+        'Record(id: r1, fields: {}, deleted: false, deletedHlc: null)',
+      );
+    });
+  });
+}

crdt_sync_flutter/scripts/check_coverage.sh

@@ -0,0 +1,32 @@
+#!/bin/bash
+
+# ============================================================================
+# Fail if lcov line coverage drops below a threshold.
+#
+# Thin delegate to the shared gate in ~/utils/scripts, which owns the parsing
+# and the threshold comparison. This file used to be a byte-identical copy of
+# that logic; three such copies existed, which is how one package's idea of
+# "covered" drifts from every other package's.
+#
+# Usage: check_coverage.sh <lcov.info> <min_percent>
+# ============================================================================
+
+set -euo pipefail
+
+# Repo-relative, resolved from this script's own location: an absolute
+# /home/... path exits 127 on an Actions runner.
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+readonly SCRIPT_DIR
+readonly SHARED_GATE="${SCRIPT_DIR}/../../scripts/check_coverage.sh"
+
+main() {
+    if [[ ! -f "$SHARED_GATE" ]]; then
+        echo "Error: shared coverage gate not found at $SHARED_GATE" >&2
+        echo "       It lives in the utils repo at scripts/check_coverage.sh." >&2
+        exit 1
+    fi
+
+    exec bash "$SHARED_GATE" "$@"
+}
+
+main "$@"

crdt_sync_flutter/test/descriptor_value_test.dart

@@ -0,0 +1,54 @@
+import 'package:crdt_sync/crdt_sync.dart';
+import 'package:crdt_sync_flutter/crdt_sync_flutter.dart';
+import 'package:flutter_test/flutter_test.dart';
+
+/// Built at runtime, not as a top-level `const`.
+///
+/// Other suites describe their app with a compile-time `const SyncApp(...)`,
+/// which the VM folds into a constant before any test body runs -- so the
+/// constructors never register as executed and read as uncovered. These
+/// helpers force real invocation.
+SyncApp _app({WrapperRoutes? routes}) => SyncApp(
+  project: const FirebaseProject(
+    apiKey: 'test-key',
+    databaseUrl: 'https://example-rtdb.europe-west1.firebasedatabase.app',
+  ),
+  expectedUid: 'uid-123',
+  routes: routes,
+);
+
+void main() {
+  group('SyncApp', () {
+    test('keeps the project and uid it was built with', () {
+      final app = _app();
+      expect(app.project.apiKey, 'test-key');
+      expect(app.expectedUid, 'uid-123');
+    });
+
+    test('routes default to null for an app with no desktop wrapper', () {
+      expect(_app().routes, isNull);
+    });
+
+    test('keeps the routes it was given', () {
+      final routes = WrapperRoutes(credentialsPath: '/sync-credentials');
+      expect(_app(routes: routes).routes, same(routes));
+    });
+  });
+
+  group('WrapperRoutes', () {
+    test('accountPath defaults to null', () {
+      final routes = WrapperRoutes(credentialsPath: '/sync-credentials');
+      expect(routes.credentialsPath, '/sync-credentials');
+      expect(routes.accountPath, isNull);
+    });
+
+    test('keeps both paths when the legacy one is supplied', () {
+      final routes = WrapperRoutes(
+        credentialsPath: '/sync-credentials',
+        accountPath: '/sync-account',
+      );
+      expect(routes.credentialsPath, '/sync-credentials');
+      expect(routes.accountPath, '/sync-account');
+    });
+  });
+}

design_system/scripts/check_coverage.sh

@@ -3,61 +3,30 @@
 # ============================================================================
 # Fail if lcov line coverage drops below a threshold.
 #
-# No Dart package in this repo has coverage enforced in CI yet -- crdt_sync_dart
-# sits at 100% by discipline, not a gate. This script is that gate for
-# sync_settings_ui, which ships as a 100%-covered shared UI package by
-# requirement, not by convention.
+# Thin delegate to the shared gate in ~/utils/scripts, which owns the parsing
+# and the threshold comparison. This file used to be a byte-identical copy of
+# that logic; three such copies existed, which is how one package's idea of
+# "covered" drifts from every other package's.
 #
 # Usage: check_coverage.sh <lcov.info> <min_percent>
 # ============================================================================
 
 set -euo pipefail
 
-SCRIPT_NAME="$(basename "$0")"
-readonly SCRIPT_NAME
+# Repo-relative, resolved from this script's own location: an absolute
+# /home/... path exits 127 on an Actions runner.
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+readonly SCRIPT_DIR
+readonly SHARED_GATE="${SCRIPT_DIR}/../../scripts/check_coverage.sh"
 
-usage() {
-    echo "Usage: $SCRIPT_NAME <lcov.info> <min_percent>"
-    echo "  Fails when line coverage in lcov.info is below min_percent."
-    exit 0
+main() {
+    if [[ ! -f "$SHARED_GATE" ]]; then
+        echo "Error: shared coverage gate not found at $SHARED_GATE" >&2
+        echo "       It lives in the utils repo at scripts/check_coverage.sh." >&2
+        exit 1
+    fi
+
+    exec bash "$SHARED_GATE" "$@"
 }
 
-if [[ "${1:-}" == "-h" || "${1:-}" == "--help" ]]; then
-    usage
-fi
-
-if [[ $# -ne 2 ]]; then
-    usage
-fi
-
-lcov_file="$1"
-min_percent="$2"
-
-if [[ ! -f "$lcov_file" ]]; then
-    echo "Error: $lcov_file not found. Run 'flutter test --coverage' first." >&2
-    exit 1
-fi
-
-# Sum LH (lines hit) and LF (lines found) across every SF (source file)
-# block rather than trusting a single top-level total -- lcov.info has no
-# such total line, only per-file LH/LF pairs.
-read -r hit found <<< "$(awk '
-    /^LH:/ { hit += substr($0, 4) }
-    /^LF:/ { found += substr($0, 4) }
-    END { print hit, found }
-' "$lcov_file")"
-
-if [[ "$found" -eq 0 ]]; then
-    echo "Error: $lcov_file reports zero coverable lines." >&2
-    exit 1
-fi
-
-percent=$(awk -v h="$hit" -v f="$found" 'BEGIN { printf "%.2f", (h / f) * 100 }')
-meets_threshold=$(awk -v p="$percent" -v m="$min_percent" 'BEGIN { print (p + 0 >= m + 0) ? 1 : 0 }')
-
-echo "Line coverage: $hit/$found ($percent%), threshold: $min_percent%"
-
-if [[ "$meets_threshold" -ne 1 ]]; then
-    echo "Error: coverage $percent% is below the required $min_percent%." >&2
-    exit 1
-fi
+main "$@"

github_device_auth/scripts/check_coverage.sh

@@ -3,61 +3,30 @@
 # ============================================================================
 # Fail if lcov line coverage drops below a threshold.
 #
-# No Dart package in this repo has coverage enforced in CI yet -- crdt_sync_dart
-# sits at 100% by discipline, not a gate. This script is that gate for
-# sync_settings_ui, which ships as a 100%-covered shared UI package by
-# requirement, not by convention.
+# Thin delegate to the shared gate in ~/utils/scripts, which owns the parsing
+# and the threshold comparison. This file used to be a byte-identical copy of
+# that logic; three such copies existed, which is how one package's idea of
+# "covered" drifts from every other package's.
 #
 # Usage: check_coverage.sh <lcov.info> <min_percent>
 # ============================================================================
 
 set -euo pipefail
 
-SCRIPT_NAME="$(basename "$0")"
-readonly SCRIPT_NAME
+# Repo-relative, resolved from this script's own location: an absolute
+# /home/... path exits 127 on an Actions runner.
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+readonly SCRIPT_DIR
+readonly SHARED_GATE="${SCRIPT_DIR}/../../scripts/check_coverage.sh"
 
-usage() {
-    echo "Usage: $SCRIPT_NAME <lcov.info> <min_percent>"
-    echo "  Fails when line coverage in lcov.info is below min_percent."
-    exit 0
+main() {
+    if [[ ! -f "$SHARED_GATE" ]]; then
+        echo "Error: shared coverage gate not found at $SHARED_GATE" >&2
+        echo "       It lives in the utils repo at scripts/check_coverage.sh." >&2
+        exit 1
+    fi
+
+    exec bash "$SHARED_GATE" "$@"
 }
 
-if [[ "${1:-}" == "-h" || "${1:-}" == "--help" ]]; then
-    usage
-fi
-
-if [[ $# -ne 2 ]]; then
-    usage
-fi
-
-lcov_file="$1"
-min_percent="$2"
-
-if [[ ! -f "$lcov_file" ]]; then
-    echo "Error: $lcov_file not found. Run 'flutter test --coverage' first." >&2
-    exit 1
-fi
-
-# Sum LH (lines hit) and LF (lines found) across every SF (source file)
-# block rather than trusting a single top-level total -- lcov.info has no
-# such total line, only per-file LH/LF pairs.
-read -r hit found <<< "$(awk '
-    /^LH:/ { hit += substr($0, 4) }
-    /^LF:/ { found += substr($0, 4) }
-    END { print hit, found }
-' "$lcov_file")"
-
-if [[ "$found" -eq 0 ]]; then
-    echo "Error: $lcov_file reports zero coverable lines." >&2
-    exit 1
-fi
-
-percent=$(awk -v h="$hit" -v f="$found" 'BEGIN { printf "%.2f", (h / f) * 100 }')
-meets_threshold=$(awk -v p="$percent" -v m="$min_percent" 'BEGIN { print (p + 0 >= m + 0) ? 1 : 0 }')
-
-echo "Line coverage: $hit/$found ($percent%), threshold: $min_percent%"
-
-if [[ "$meets_threshold" -ne 1 ]]; then
-    echo "Error: coverage $percent% is below the required $min_percent%." >&2
-    exit 1
-fi
+main "$@"

scripts/check_coverage.sh

@@ -0,0 +1,70 @@
+#!/bin/bash
+
+# ============================================================================
+# Fail if lcov line coverage drops below a threshold.
+#
+# THE shared coverage gate for every package in this repo. Three byte-identical
+# copies of this file used to live under design_system/, github_device_auth/
+# and sync_settings_ui/scripts/ -- each claiming in its own header to exist for
+# one particular package. Those are now thin delegates to this file, for the
+# same reason check_file_length.sh is shared: a per-package copy is how one
+# package's idea of "covered" drifts from every other package's.
+#
+# Note for pure-Dart packages: `dart test --coverage` writes raw VM JSON, NOT
+# lcov. Run coverage:format_coverage before this gate, or it will happily pass
+# against a stale lcov.info from a previous run. crdt_sync_dart really did sit
+# at 96% for three weeks that way while believing it was at 100%.
+#
+# Usage: check_coverage.sh <lcov.info> <min_percent>
+# ============================================================================
+
+set -euo pipefail
+
+SCRIPT_NAME="$(basename "$0")"
+readonly SCRIPT_NAME
+
+usage() {
+    echo "Usage: $SCRIPT_NAME <lcov.info> <min_percent>"
+    echo "  Fails when line coverage in lcov.info is below min_percent."
+    exit 0
+}
+
+if [[ "${1:-}" == "-h" || "${1:-}" == "--help" ]]; then
+    usage
+fi
+
+if [[ $# -ne 2 ]]; then
+    usage
+fi
+
+lcov_file="$1"
+min_percent="$2"
+
+if [[ ! -f "$lcov_file" ]]; then
+    echo "Error: $lcov_file not found. Run 'flutter test --coverage' first." >&2
+    exit 1
+fi
+
+# Sum LH (lines hit) and LF (lines found) across every SF (source file)
+# block rather than trusting a single top-level total -- lcov.info has no
+# such total line, only per-file LH/LF pairs.
+read -r hit found <<< "$(awk '
+    /^LH:/ { hit += substr($0, 4) }
+    /^LF:/ { found += substr($0, 4) }
+    END { print hit, found }
+' "$lcov_file")"
+
+if [[ "$found" -eq 0 ]]; then
+    echo "Error: $lcov_file reports zero coverable lines." >&2
+    exit 1
+fi
+
+percent=$(awk -v h="$hit" -v f="$found" 'BEGIN { printf "%.2f", (h / f) * 100 }')
+meets_threshold=$(awk -v p="$percent" -v m="$min_percent" 'BEGIN { print (p + 0 >= m + 0) ? 1 : 0 }')
+
+echo "Line coverage: $hit/$found ($percent%), threshold: $min_percent%"
+
+if [[ "$meets_threshold" -ne 1 ]]; then
+    echo "Error: coverage $percent% is below the required $min_percent%." >&2
+    exit 1
+fi

sync_settings_ui/scripts/check_coverage.sh

@@ -3,61 +3,30 @@
 # ============================================================================
 # Fail if lcov line coverage drops below a threshold.
 #
-# No Dart package in this repo has coverage enforced in CI yet -- crdt_sync_dart
-# sits at 100% by discipline, not a gate. This script is that gate for
-# sync_settings_ui, which ships as a 100%-covered shared UI package by
-# requirement, not by convention.
+# Thin delegate to the shared gate in ~/utils/scripts, which owns the parsing
+# and the threshold comparison. This file used to be a byte-identical copy of
+# that logic; three such copies existed, which is how one package's idea of
+# "covered" drifts from every other package's.
 #
 # Usage: check_coverage.sh <lcov.info> <min_percent>
 # ============================================================================
 
 set -euo pipefail
 
-SCRIPT_NAME="$(basename "$0")"
-readonly SCRIPT_NAME
+# Repo-relative, resolved from this script's own location: an absolute
+# /home/... path exits 127 on an Actions runner.
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+readonly SCRIPT_DIR
+readonly SHARED_GATE="${SCRIPT_DIR}/../../scripts/check_coverage.sh"
 
-usage() {
-    echo "Usage: $SCRIPT_NAME <lcov.info> <min_percent>"
-    echo "  Fails when line coverage in lcov.info is below min_percent."
-    exit 0
+main() {
+    if [[ ! -f "$SHARED_GATE" ]]; then
+        echo "Error: shared coverage gate not found at $SHARED_GATE" >&2
+        echo "       It lives in the utils repo at scripts/check_coverage.sh." >&2
+        exit 1
+    fi
+
+    exec bash "$SHARED_GATE" "$@"
 }
 
-if [[ "${1:-}" == "-h" || "${1:-}" == "--help" ]]; then
-    usage
-fi
-
-if [[ $# -ne 2 ]]; then
-    usage
-fi
-
-lcov_file="$1"
-min_percent="$2"
-
-if [[ ! -f "$lcov_file" ]]; then
-    echo "Error: $lcov_file not found. Run 'flutter test --coverage' first." >&2
-    exit 1
-fi
-
-# Sum LH (lines hit) and LF (lines found) across every SF (source file)
-# block rather than trusting a single top-level total -- lcov.info has no
-# such total line, only per-file LH/LF pairs.
-read -r hit found <<< "$(awk '
-    /^LH:/ { hit += substr($0, 4) }
-    /^LF:/ { found += substr($0, 4) }
-    END { print hit, found }
-' "$lcov_file")"
-
-if [[ "$found" -eq 0 ]]; then
-    echo "Error: $lcov_file reports zero coverable lines." >&2
-    exit 1
-fi
-
-percent=$(awk -v h="$hit" -v f="$found" 'BEGIN { printf "%.2f", (h / f) * 100 }')
-meets_threshold=$(awk -v p="$percent" -v m="$min_percent" 'BEGIN { print (p + 0 >= m + 0) ? 1 : 0 }')
-
-echo "Line coverage: $hit/$found ($percent%), threshold: $min_percent%"
-
-if [[ "$meets_threshold" -ne 1 ]]; then
-    echo "Error: coverage $percent% is below the required $min_percent%." >&2
-    exit 1
-fi
+main "$@"