Remove hidden dependencies on the default LocalPlatform (#147342)

This is part 13 of a broken down version of the #140101 refactor.

This only makes one dependency explicit. Further PRs will do the same
for other dependencies, until these APIs have no hidden dependencies.

Author: Hixie

packages/flutter_goldens/lib/flutter_goldens.dart

@@ -59,15 +59,15 @@ Future<void> testExecutable(FutureOr<void> Function() testMain, {String? namePre
   if (FlutterPostSubmitFileComparator.isForEnvironment(platform)) {
     goldenFileComparator = await FlutterPostSubmitFileComparator.fromLocalFileComparator(
       localFileComparator: goldenFileComparator as LocalFileComparator,
-      platform,
+      platform: platform,
       namePrefix: namePrefix,
       log: print,
       fs: fs,
     );
   } else if (FlutterPreSubmitFileComparator.isForEnvironment(platform)) {
     goldenFileComparator = await FlutterPreSubmitFileComparator.fromLocalFileComparator(
       localFileComparator: goldenFileComparator as LocalFileComparator,
-      platform,
+      platform: platform,
       namePrefix: namePrefix,
       log: print,
       fs: fs,
@@ -78,14 +78,15 @@ Future<void> testExecutable(FutureOr<void> Function() testMain, {String? namePre
       'Golden file testing is not executed on Cirrus, or LUCI environments '
       'outside of flutter/flutter, or in test shards that are not configured '
       'for using goldctl.',
+      platform: platform,
       namePrefix: namePrefix,
       log: print,
       fs: fs,
     );
   } else {
     goldenFileComparator = await FlutterLocalFileComparator.fromLocalFileComparator(
       localFileComparator: goldenFileComparator as LocalFileComparator,
-      platform,
+      platform: platform,
       log: print,
       fs: fs,
     );
@@ -133,15 +134,12 @@ abstract class FlutterGoldenFileComparator extends GoldenFileComparator {
   /// information and files for interacting with the [skiaClient]. When testing
   /// locally, the [basedir] will also contain any diffs from failed tests, or
   /// goldens generated from newly introduced tests.
-  ///
-  /// The [platform] parameter is useful in tests, where the default
-  /// platform can be replaced by a mock instance.
   @visibleForTesting
   FlutterGoldenFileComparator(
     this.basedir,
     this.skiaClient, {
     required this.fs,
-    this.platform = const LocalPlatform(),
+    required this.platform,
     this.namePrefix,
     required this.log,
   });
@@ -157,8 +155,8 @@ abstract class FlutterGoldenFileComparator extends GoldenFileComparator {
   /// The file system used to perform file access.
   final FileSystem fs;
 
-  /// A wrapper for the [dart:io.Platform] API.
-  @visibleForTesting
+  /// The environment (current working directory, identity of the OS,
+  /// environment variables, etc).
   final Platform platform;
 
   /// The prefix that is added to all golden names.
@@ -186,8 +184,8 @@ abstract class FlutterGoldenFileComparator extends GoldenFileComparator {
   @protected
   @visibleForTesting
   static Directory getBaseDirectory(
-    LocalFileComparator defaultComparator,
-    Platform platform, {
+    LocalFileComparator defaultComparator, {
+    required Platform platform,
     String? suffix,
     required FileSystem fs,
   }) {
@@ -260,13 +258,13 @@ class FlutterPostSubmitFileComparator extends FlutterGoldenFileComparator {
   /// Creates a [FlutterPostSubmitFileComparator] that will test golden file
   /// images against Skia Gold.
   ///
-  /// The [fs] and [platform] parameters are useful in tests, where the default
-  /// file system and platform can be replaced by mock instances.
+  /// The [fs] parameter is useful in tests, where the default
+  /// file system can be replaced by mock instances.
   FlutterPostSubmitFileComparator(
     super.basedir,
     super.skiaClient, {
     required super.fs,
-    super.platform,
+    required super.platform,
     super.namePrefix,
     required super.log,
   });
@@ -275,27 +273,32 @@ class FlutterPostSubmitFileComparator extends FlutterGoldenFileComparator {
   /// path resolution of the provided `localFileComparator`.
   ///
   /// The [goldens] parameter is visible for testing purposes only.
-  static Future<FlutterPostSubmitFileComparator> fromLocalFileComparator(
-    final Platform platform, {
+  static Future<FlutterPostSubmitFileComparator> fromLocalFileComparator({
     SkiaGoldClient? goldens,
     required LocalFileComparator localFileComparator,
+    required Platform platform,
     String? namePrefix,
     required LogCallback log,
     required FileSystem fs,
   }) async {
     final Directory baseDirectory = FlutterGoldenFileComparator.getBaseDirectory(
       localFileComparator,
-      platform,
+      platform: platform,
       suffix: 'flutter_goldens_postsubmit.',
       fs: fs,
     );
     baseDirectory.createSync(recursive: true);
 
-    goldens ??= SkiaGoldClient(baseDirectory, log: log);
+    goldens ??= SkiaGoldClient(
+      baseDirectory,
+      log: log,
+      platform: platform,
+    );
     await goldens.auth();
     return FlutterPostSubmitFileComparator(
       baseDirectory.uri,
       goldens,
+      platform: platform,
       namePrefix: namePrefix,
       log: log,
       fs: fs,
@@ -342,13 +345,13 @@ class FlutterPreSubmitFileComparator extends FlutterGoldenFileComparator {
   /// Creates a [FlutterPreSubmitFileComparator] that will test golden file
   /// images against baselines requested from Flutter Gold.
   ///
-  /// The [fs] and [platform] parameters are useful in tests, where the default
-  /// file system and platform can be replaced by mock instances.
+  /// The [fs] parameter is useful in tests, where the default
+  /// file system can be replaced by mock instances.
   FlutterPreSubmitFileComparator(
     super.basedir,
     super.skiaClient, {
     required super.fs,
-    super.platform,
+    required super.platform,
     super.namePrefix,
     required super.log,
   });
@@ -357,18 +360,18 @@ class FlutterPreSubmitFileComparator extends FlutterGoldenFileComparator {
   /// relative path resolution of the default [goldenFileComparator].
   ///
   /// The [goldens] parameter is visible for testing purposes only.
-  static Future<FlutterGoldenFileComparator> fromLocalFileComparator(
-    final Platform platform, {
+  static Future<FlutterGoldenFileComparator> fromLocalFileComparator({
     SkiaGoldClient? goldens,
     required LocalFileComparator localFileComparator,
+    required Platform platform,
     Directory? testBasedir,
     String? namePrefix,
     required LogCallback log,
     required FileSystem fs,
   }) async {
     final Directory baseDirectory = testBasedir ?? FlutterGoldenFileComparator.getBaseDirectory(
       localFileComparator,
-      platform,
+      platform: platform,
       suffix: 'flutter_goldens_presubmit.',
       fs: fs,
     );
@@ -377,12 +380,17 @@ class FlutterPreSubmitFileComparator extends FlutterGoldenFileComparator {
       baseDirectory.createSync(recursive: true);
     }
 
-    goldens ??= SkiaGoldClient(baseDirectory, log: log);
+    goldens ??= SkiaGoldClient(
+      baseDirectory,
+      platform: platform,
+      log: log,
+    );
 
     await goldens.auth();
     return FlutterPreSubmitFileComparator(
       baseDirectory.uri,
-      goldens, platform: platform,
+      goldens,
+      platform: platform,
       namePrefix: namePrefix,
       log: log,
       fs: fs,
@@ -439,6 +447,7 @@ class FlutterSkippingFileComparator extends FlutterGoldenFileComparator {
     super.skiaClient,
     this.reason, {
     super.namePrefix,
+    required super.platform,
     required super.log,
     required super.fs,
   });
@@ -452,16 +461,22 @@ class FlutterSkippingFileComparator extends FlutterGoldenFileComparator {
     String reason, {
     required LocalFileComparator localFileComparator,
     String? namePrefix,
+    required Platform platform,
     required LogCallback log,
     required FileSystem fs,
   }) {
     final Uri basedir = localFileComparator.basedir;
-    final SkiaGoldClient skiaClient = SkiaGoldClient(fs.directory(basedir), log: log);
+    final SkiaGoldClient skiaClient = SkiaGoldClient(
+      fs.directory(basedir),
+      platform: platform,
+      log: log,
+    );
     return FlutterSkippingFileComparator(
       basedir,
       skiaClient,
       reason,
       namePrefix: namePrefix,
+      platform: platform,
       log: log,
       fs: fs,
     );
@@ -519,13 +534,13 @@ class FlutterLocalFileComparator extends FlutterGoldenFileComparator with LocalC
   /// Creates a [FlutterLocalFileComparator] that will test golden file
   /// images against baselines requested from Flutter Gold.
   ///
-  /// The [fs] and [platform] parameters are useful in tests, where the default
-  /// file system and platform can be replaced by mock instances.
+  /// The [fs] parameter is useful in tests, where the default
+  /// file system can be replaced by mock instances.
   FlutterLocalFileComparator(
     super.basedir,
     super.skiaClient, {
     required super.fs,
-    super.platform,
+    required super.platform,
     required super.log,
   });
 
@@ -534,25 +549,29 @@ class FlutterLocalFileComparator extends FlutterGoldenFileComparator with LocalC
   ///
   /// The [goldens] and [baseDirectory] parameters are
   /// visible for testing purposes only.
-  static Future<FlutterGoldenFileComparator> fromLocalFileComparator(
-    final Platform platform, {
+  static Future<FlutterGoldenFileComparator> fromLocalFileComparator({
     SkiaGoldClient? goldens,
     required LocalFileComparator localFileComparator,
+    required Platform platform,
     Directory? baseDirectory,
     required LogCallback log,
     required FileSystem fs,
   }) async {
     baseDirectory ??= FlutterGoldenFileComparator.getBaseDirectory(
       localFileComparator,
-      platform,
+      platform: platform,
       fs: fs,
     );
 
     if (!baseDirectory.existsSync()) {
       baseDirectory.createSync(recursive: true);
     }
 
-    goldens ??= SkiaGoldClient(baseDirectory, log: log);
+    goldens ??= SkiaGoldClient(
+      baseDirectory,
+      platform: platform,
+      log: log,
+    );
     try {
       // Check if we can reach Gold.
       await goldens.getExpectationForTest('');
@@ -562,6 +581,7 @@ class FlutterLocalFileComparator extends FlutterGoldenFileComparator with LocalC
         goldens,
         'OSError occurred, could not reach Gold. '
         'Switching to FlutterSkippingGoldenFileComparator.',
+        platform: platform,
         log: log,
         fs: fs,
       );
@@ -571,6 +591,7 @@ class FlutterLocalFileComparator extends FlutterGoldenFileComparator with LocalC
         goldens,
         'SocketException occurred, could not reach Gold. '
         'Switching to FlutterSkippingGoldenFileComparator.',
+        platform: platform,
         log: log,
         fs: fs,
       );
@@ -580,6 +601,7 @@ class FlutterLocalFileComparator extends FlutterGoldenFileComparator with LocalC
         goldens,
         'FormatException occurred, could not reach Gold. '
         'Switching to FlutterSkippingGoldenFileComparator.',
+        platform: platform,
         log: log,
         fs: fs,
       );
@@ -588,6 +610,7 @@ class FlutterLocalFileComparator extends FlutterGoldenFileComparator with LocalC
     return FlutterLocalFileComparator(
       baseDirectory.uri,
       goldens,
+      platform: platform,
       log: log,
       fs: fs,
     );

packages/flutter_goldens/lib/skia_client.dart

@@ -44,15 +44,15 @@ class SkiaException implements Exception {
 /// A client for uploading image tests and making baseline requests to the
 /// Flutter Gold Dashboard.
 class SkiaGoldClient {
-  /// Creates a [SkiaGoldClient] with the given [workDirectory].
+  /// Creates a [SkiaGoldClient] with the given [workDirectory] and [Platform].
   ///
   /// All other parameters are optional. They may be provided in tests to
-  /// override the defaults for [fs], [process], [platform], and [httpClient].
+  /// override the defaults for [fs], [process], and [httpClient].
   SkiaGoldClient(
     this.workDirectory, {
     this.fs = const LocalFileSystem(),
     this.process = const LocalProcessManager(),
-    this.platform = const LocalPlatform(),
+    required this.platform,
     Abi? abi,
     io.HttpClient? httpClient,
     required this.log,
@@ -65,10 +65,8 @@ class SkiaGoldClient {
   /// replaced by a memory file system.
   final FileSystem fs;
 
-  /// A wrapper for the [dart:io.Platform] API.
-  ///
-  /// This is useful in tests, where the system platform (the default) can be
-  /// replaced by a mock platform instance.
+  /// The environment (current working directory, identity of the OS,
+  /// environment variables, etc).
   final Platform platform;
 
   /// A controller for launching sub-processes.

packages/flutter_goldens/test/flutter_goldens_test.dart

@@ -716,7 +716,7 @@ void main() {
       defaultComparator.basedir = flutterRoot.childDirectory('baz').uri;
       final Directory basedir = FlutterGoldenFileComparator.getBaseDirectory(
         defaultComparator,
-        platform,
+        platform: platform,
         fs: fs,
       );
       expect(
@@ -854,7 +854,7 @@ void main() {
         expect(fakeSkiaClient.initCalls, 0);
         FlutterPostSubmitFileComparator.fromLocalFileComparator(
           localFileComparator: LocalFileComparator(Uri.parse('/test'), pathStyle: path.Style.posix),
-          platform,
+          platform: platform,
           goldens: fakeSkiaClient,
           log: (String message) => fail('skia gold client printed unexpected output: "$message"'),
           fs: fs,
@@ -940,7 +940,7 @@ void main() {
         expect(fakeSkiaClient.tryInitCalls, 0);
         FlutterPostSubmitFileComparator.fromLocalFileComparator(
           localFileComparator: LocalFileComparator(Uri.parse('/test'), pathStyle: path.Style.posix),
-          platform,
+          platform: platform,
           goldens: fakeSkiaClient,
           log: (String message) => fail('skia gold client printed unexpected output: "$message"'),
           fs: fs,
@@ -1042,7 +1042,7 @@ void main() {
         fakeSkiaClient.getExpectationForTestThrowable = const OSError("Can't reach Gold");
         final FlutterGoldenFileComparator comparator1 = await FlutterLocalFileComparator.fromLocalFileComparator(
           localFileComparator: LocalFileComparator(Uri.parse('/test'), pathStyle: path.Style.posix),
-          platform,
+          platform: platform,
           goldens: fakeSkiaClient,
           baseDirectory: fakeDirectory,
           log: (String message) => fail('skia gold client printed unexpected output: "$message"'),
@@ -1053,7 +1053,7 @@ void main() {
         fakeSkiaClient.getExpectationForTestThrowable =  const SocketException("Can't reach Gold");
         final FlutterGoldenFileComparator comparator2 = await FlutterLocalFileComparator.fromLocalFileComparator(
           localFileComparator: LocalFileComparator(Uri.parse('/test'), pathStyle: path.Style.posix),
-          platform,
+          platform: platform,
           goldens: fakeSkiaClient,
           baseDirectory: fakeDirectory,
           log: (String message) => fail('skia gold client printed unexpected output: "$message"'),
@@ -1064,7 +1064,7 @@ void main() {
         fakeSkiaClient.getExpectationForTestThrowable =  const FormatException("Can't reach Gold");
         final FlutterGoldenFileComparator comparator3 = await FlutterLocalFileComparator.fromLocalFileComparator(
           localFileComparator: LocalFileComparator(Uri.parse('/test'), pathStyle: path.Style.posix),
-          platform,
+          platform: platform,
           goldens: fakeSkiaClient,
           baseDirectory: fakeDirectory,
           log: (String message) => fail('skia gold client printed unexpected output: "$message"'),