Use the VM's "platform-const" feature to achieve tree-shaking.

.github/workflows/test-package.yml

@@ -47,7 +47,7 @@ jobs:
       matrix:
         # Add macos-latest and/or windows-latest if relevant for this package.
         os: [ubuntu-latest, windows-latest, macos-latest]
-        sdk: [2.18.0, dev]
+        sdk: [3.0.0, dev]
     steps:
       - uses: actions/checkout@c85c95e3d7251135ab7dc9ce3241c5835cc595a9
       - uses: dart-lang/setup-dart@d6a63dab3335f427404425de0fbfed4686d93c4f

CHANGELOG.md

@@ -1,6 +1,7 @@
 ## 2.0.2-dev
 
-- Require Dart 2.18
+- Require Dart 3.0
+- Make work with VM's platform-constants.
 
 ## 2.0.1
 

analysis_options.yaml

@@ -14,42 +14,55 @@ linter:
   - avoid_catching_errors
   - avoid_classes_with_only_static_members
   - avoid_dynamic_calls
+  - avoid_empty_else
   - avoid_private_typedef_functions
   - avoid_redundant_argument_values
-  - avoid_returning_null_for_future
+  - avoid_relative_lib_imports
   - avoid_returning_this
+  - avoid_shadowing_type_parameters
+  - avoid_types_as_parameter_names
   - avoid_unused_constructor_parameters
   - avoid_void_async
-  - cancel_subscriptions
+  - await_only_futures
+  - camel_case_extensions
+  - collection_methods_unrelated_type
   - comment_references
+  - curly_braces_in_flow_control_structures
   - directives_ordering
-  - join_return_with_assignment
+  - empty_catches
+  - file_names
+  - hash_and_equals
   - lines_longer_than_80_chars
   - literal_only_boolean_expressions
   - missing_whitespace_between_adjacent_strings
   - no_adjacent_strings_in_list
+  - no_duplicate_case_values
   - no_runtimeType_toString
   - omit_local_variable_types
   - only_throw_errors
   - package_api_docs
   - prefer_asserts_in_initializer_lists
-  - prefer_const_constructors
   - prefer_const_declarations
-  - prefer_expression_function_bodies
-  - prefer_final_locals
+  - prefer_generic_function_type_aliases
+  - prefer_is_empty
+  - prefer_is_not_empty
+  - prefer_iterable_whereType
   - prefer_relative_imports
   - prefer_single_quotes
+  - prefer_typing_uninitialized_variables
+  - provide_deprecation_message
   - sort_pub_dependencies
   - test_types_in_equals
   - throw_in_finally
   - type_annotate_public_apis
   - unawaited_futures
-  - unnecessary_await_in_return
   - unnecessary_lambdas
+  - unnecessary_overrides
   - unnecessary_parenthesis
-  - unnecessary_raw_strings
   - unnecessary_statements
-  - use_if_null_to_convert_nulls_to_bools
+  - unrelated_type_equality_checks
+  - use_is_even_rather_than_modulo
+  - void_checks
   - use_raw_strings
-  - use_string_buffers
-  - use_super_parameters
+
+

bin/os_detect.dart

@@ -0,0 +1,40 @@
+// Copyright (c) 2023, 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.
+
+/// Prints the operating system detected by the current compilation environment.
+library pkg.os_detect.run;
+
+import 'package:os_detect/os_detect.dart' as os_detect;
+
+void main() {
+  final knownName = knownOSName();
+  print('OS name    : ${os_detect.operatingSystem} '
+      '${knownName != null ? '($knownName)' : ''}');
+  print('OS version : ${os_detect.operatingSystemVersion}');
+}
+
+String? knownOSName() {
+  if (os_detect.isAndroid) {
+    return 'Android';
+  }
+  if (os_detect.isBrowser) {
+    return 'Browser';
+  }
+  if (os_detect.isFuchsia) {
+    return 'Fuchsia';
+  }
+  if (os_detect.isIOS) {
+    return 'iOS';
+  }
+  if (os_detect.isLinux) {
+    return 'Linux';
+  }
+  if (os_detect.isMacOS) {
+    return 'MacOS';
+  }
+  if (os_detect.isWindows) {
+    return 'Windows';
+  }
+  return null;
+}

example/example.dart

@@ -6,7 +6,21 @@ import 'package:os_detect/os_detect.dart' as os_detect;
 
 void main() {
   print('''
-        OS: ${os_detect.operatingSystem}
-OS Version: ${os_detect.operatingSystemVersion}
-''');
+     OS ID: ${os_detect.operatingSystem}
+OS Version: ${os_detect.operatingSystemVersion}''');
+  if (os_detect.isAndroid) {
+    print('   OS Type: Android');
+  } else if (os_detect.isBrowser) {
+    print('   OS Type: Browser');
+  } else if (os_detect.isFuchsia) {
+    print('   OS Type: Fuchsia');
+  } else if (os_detect.isIOS) {
+    print('   OS Type: iOS');
+  } else if (os_detect.isLinux) {
+    print('   OS Type: Linux');
+  } else if (os_detect.isMacOS) {
+    print('   OS Type: MacOS');
+  } else if (os_detect.isWindows) {
+    print('   OS Type: Windows');
+  }
 }

example/tree_shaking.dart

@@ -0,0 +1,29 @@
+// Copyright (c) 2023, 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.
+
+// Try compiling this example with (if on Linux):
+//
+//   dart compile exe --target-os=linux tree_shaking.dart
+//
+// then check that "SOMETHING ELSE" does not occur in the
+// output `tree_shaking.exe` program, e.g.:
+//
+//   strings tree_shaking.exe | grep SOMETHING
+//
+// which shows no matches.
+
+import 'package:os_detect/os_detect.dart' as platform;
+
+void main() {
+  if (platform.isLinux) {
+    print('Is Linux');
+  } else {
+    print('SOMETHING ELSE');
+  }
+  if (platform.operatingSystem == 'linux') {
+    print('Is Linux');
+  } else {
+    print('SOMETHING ELSE');
+  }
+}

lib/os_detect.dart

@@ -5,11 +5,19 @@
 /// Information about the current operating system.
 library pkg.os_detect;
 
-import 'override.dart';
+import 'src/os_override.dart';
 
 /// Identification of the current operating system or platform.
 ///
-/// Specific known operating systems are reported by a unique string.
+/// Specific known operating systems are reported by a unique known string,
+/// and all the `is<Name>` values are computed by comparing the
+/// [operatingSystem] string against those known strings.
+/// That means that *at most* one of those value can be `true`,
+/// and usually precisely one will be `true`.
+///
+/// **Notice:** Programs running in a browser will report their
+/// operating system as `"browser"`, not the operating system
+/// that browser is running on. See [isBrowser].
 String get operatingSystem => OperatingSystem.current.id;
 
 /// Representation of the version of the current operating system or platform.
@@ -24,37 +32,59 @@ String get operatingSystemVersion => OperatingSystem.current.version;
 ///
 /// This value is `false` if the operating system is a specialized
 /// version of Linux that identifies itself by a different name,
-/// for example Android (see [isAndroid]).
+/// for example Android (see [isAndroid]),
+/// or if the code is running inside a browser (see [isBrowser]).
+@pragma('vm:prefer-inline')
 bool get isLinux => OperatingSystem.current.isLinux;
 
 /// Whether the current operating system is a version of
 /// [macOS](https://en.wikipedia.org/wiki/MacOS).
 ///
 /// Identified by [operatingSystem] being the string `macos`.
+///
+/// The value is `false` if the code is running inside a browser,
+/// even if that browser is running on MacOS (see [isBrowser]).
+@pragma('vm:prefer-inline')
 bool get isMacOS => OperatingSystem.current.isMacOS;
 
 /// Whether the current operating system is a version of
 /// [Microsoft Windows](https://en.wikipedia.org/wiki/Microsoft_Windows).
 ///
 /// Identified by [operatingSystem] being the string `windows`.
+///
+/// The value is `false` if the code is running inside a browser,
+/// even if that browser is running on Windows (see [isBrowser]).
+@pragma('vm:prefer-inline')
 bool get isWindows => OperatingSystem.current.isWindows;
 
 /// Whether the current operating system is a version of
 /// [Android](https://en.wikipedia.org/wiki/Android_%28operating_system%29).
 ///
 /// Identified by [operatingSystem] being the string `android`.
+///
+/// The value is `false` if the code is running inside a browser,
+/// even if that browser is running on Android (see [isBrowser]).
+@pragma('vm:prefer-inline')
 bool get isAndroid => OperatingSystem.current.isAndroid;
 
 /// Whether the current operating system is a version of
 /// [iOS](https://en.wikipedia.org/wiki/IOS).
 ///
 /// Identified by [operatingSystem] being the string `ios`.
+///
+/// The value is `false` if the code is running inside a browser,
+/// even if that browser is running on iOS (see [isBrowser]).
+@pragma('vm:prefer-inline')
 bool get isIOS => OperatingSystem.current.isIOS;
 
 /// Whether the current operating system is a version of
 /// [Fuchsia](https://en.wikipedia.org/wiki/Google_Fuchsia).
 ///
 /// Identified by [operatingSystem] being the string `fuchsia`.
+///
+/// The value is `false` if the code is running inside a browser,
+/// even if that browser is running on Fuchsia (see [isBrowser]).
+@pragma('vm:prefer-inline')
 bool get isFuchsia => OperatingSystem.current.isFuchsia;
 
 /// Whether running in a web browser.
@@ -63,4 +93,12 @@ bool get isFuchsia => OperatingSystem.current.isFuchsia;
 ///
 /// If so, the [operatingSystemVersion] is the string made available
 /// through `window.navigator.appVersion`.
+///
+/// The value is `true` when the code is running inside a browser,
+/// no matter which operating system the browser is itself running on.
+/// No attempt is made to detect the underlying operating system.
+/// That information *may* be derived from [operatingSystemVersion],
+/// but browsers are able to lie in the app-version/user-agent
+/// string.
+@pragma('vm:prefer-inline')
 bool get isBrowser => OperatingSystem.current.isBrowser;

lib/override.dart

@@ -1,100 +1,8 @@
-// Copyright (c) 2020, the Dart project authors.  Please see the AUTHORS file
+// Copyright (c) 2023, 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.
 
 /// Functionality to override information about the current platform.
-library pkg.os_detect.override;
+library;
 
-import 'dart:async' show Zone, runZoned;
-
-import 'src/osid_unknown.dart'
-    if (dart.library.io) 'src/osid_io.dart'
-    if (dart.library.html) 'src/osid_html.dart';
-
-/// The name and version of an operating system.
-class OperatingSystem {
-  /// The current operating system ID.
-  ///
-  /// Defaults to what information is available
-  /// from known platform specific libraries,
-  /// but can be overridden using functionality from the
-  /// `osid_override.dart` library.
-  static OperatingSystem get current =>
-      Zone.current[#_os] as OperatingSystem? ?? platformOS;
-
-  /// A string representing the operating system or platform.
-  final String id;
-
-  /// A string representing the version of the operating system or platform.
-  ///
-  /// May be empty if no version is known or available.
-  final String version;
-
-  /// Creates an operating system ID with the provided values.
-  const OperatingSystem(this.id, this.version);
-}
-
-/// Convenience operations on [OperatingSystem].
-///
-/// Implemented as extensions to allow users to *implement* [OperatingSystem]
-/// without having to implement all of these getters.
-extension OperatingSystemGetters on OperatingSystem {
-  /// Whether the operating system is a version of
-  /// [Linux](https://en.wikipedia.org/wiki/Linux).
-  ///
-  /// Identified by [id] being the string `linux`.
-  ///
-  /// This value is `false` if the operating system is a specialized
-  /// version of Linux that identifies itself by a different name,
-  /// for example Android (see [isAndroid]).
-  bool get isLinux => 'linux' == id;
-
-  /// Whether the operating system is a version of
-  /// [macOS](https://en.wikipedia.org/wiki/MacOS).
-  ///
-  /// Identified by [id] being the string `macos`.
-  bool get isMacOS => 'macos' == id;
-
-  /// Whether the operating system is a version of
-  /// [Microsoft Windows](https://en.wikipedia.org/wiki/Microsoft_Windows).
-  ///
-  /// Identified by [id] being the string `windows`.
-  bool get isWindows => 'windows' == id;
-
-  /// Whether the operating system is a version of
-  /// [Android](https://en.wikipedia.org/wiki/Android_%28operating_system%29).
-  ///
-  /// Identified by [id] being the string `android`.
-  bool get isAndroid => 'android' == id;
-
-  /// Whether the operating system is a version of
-  /// [iOS](https://en.wikipedia.org/wiki/IOS).
-  ///
-  /// Identified by [id] being the string `ios`.
-  bool get isIOS => 'ios' == id;
-
-  /// Whether the operating system is a version of
-  /// [Fuchsia](https://en.wikipedia.org/wiki/Google_Fuchsia).
-  ///
-  /// Identified by [id] being the string `fuchsia`.
-  bool get isFuchsia => 'fuchsia' == id;
-
-  /// Whether running in a web browser.
-  ///
-  /// Identified by [id] being the string `browser`.
-  ///
-  /// If so, the [version] is the string made available
-  /// through `window.navigator.appVersion`.
-  bool get isBrowser => 'browser' == id;
-}
-
-/// Run [body] in a zone with platform overrides.
-///
-/// Overrides [OperatingSystem.current] with the supplied [operatingSystem]
-/// value while running in a new zone, and then runs [body] in that zone.
-///
-/// This override affects the `operatingSystem` and `version`
-/// exported by `package:osid/osid.dart`.
-R overrideOperatingSystem<R>(
-        OperatingSystem operatingSystem, R Function() body) =>
-    runZoned(body, zoneValues: {#_os: operatingSystem});
+export 'src/os_override.dart' show OperatingSystem, overrideOperatingSystem;