[flutter_tools] experiment with skipping process resolution (#74447)

packages/flutter_tools/lib/src/base/error_handling_io.dart

@@ -575,6 +575,70 @@ T _runSync<T>(T Function() op, {
   }
 }
 
+class _ProcessDelegate {
+  const _ProcessDelegate();
+
+  Future<io.Process> start(
+    List<String> command, {
+    String workingDirectory,
+    Map<String, String> environment,
+    bool includeParentEnvironment = true,
+    bool runInShell = false,
+    io.ProcessStartMode mode = io.ProcessStartMode.normal,
+  }) {
+    return io.Process.start(
+      command[0],
+      command.skip(1).toList(),
+      workingDirectory: workingDirectory,
+      environment: environment,
+      includeParentEnvironment: includeParentEnvironment,
+      runInShell: runInShell,
+    );
+  }
+
+  Future<io.ProcessResult> run(
+    List<String> command, {
+    String workingDirectory,
+    Map<String, String> environment,
+    bool includeParentEnvironment = true,
+    bool runInShell = false,
+    Encoding stdoutEncoding = io.systemEncoding,
+    Encoding stderrEncoding = io.systemEncoding,
+  }) {
+    return io.Process.run(
+      command[0],
+      command.skip(1).toList(),
+      workingDirectory: workingDirectory,
+      environment: environment,
+      includeParentEnvironment: includeParentEnvironment,
+      runInShell: runInShell,
+      stdoutEncoding: stdoutEncoding,
+      stderrEncoding: stderrEncoding,
+    );
+  }
+
+  io.ProcessResult runSync(
+    List<String> command, {
+    String workingDirectory,
+    Map<String, String> environment,
+    bool includeParentEnvironment = true,
+    bool runInShell = false,
+    Encoding stdoutEncoding = io.systemEncoding,
+    Encoding stderrEncoding = io.systemEncoding,
+  }) {
+    return io.Process.runSync(
+      command[0],
+      command.skip(1).toList(),
+      workingDirectory: workingDirectory,
+      environment: environment,
+      includeParentEnvironment: includeParentEnvironment,
+      runInShell: runInShell,
+      stdoutEncoding: stdoutEncoding,
+      stderrEncoding: stderrEncoding,
+    );
+  }
+}
+
 /// A [ProcessManager] that throws a [ToolExit] on certain errors.
 ///
 /// If a [ProcessException] is not caused by the Flutter tool, and can only be
@@ -592,6 +656,21 @@ class ErrorHandlingProcessManager extends ProcessManager {
 
   final ProcessManager _delegate;
   final Platform _platform;
+  static const _ProcessDelegate _processDelegate = _ProcessDelegate();
+  static bool _skipCommandLookup = false;
+
+  /// Bypass package:process command lookup for all functions in this block.
+  ///
+  /// This required that the fully resolved executable path is provided.
+  static Future<T> skipCommandLookup<T>(Future<T> Function() operation) async {
+    final bool previousValue = ErrorHandlingProcessManager._skipCommandLookup;
+    try {
+      ErrorHandlingProcessManager._skipCommandLookup = true;
+      return await operation();
+    } finally {
+      ErrorHandlingProcessManager._skipCommandLookup = previousValue;
+    }
+  }
 
   @override
   bool canRun(dynamic executable, {String workingDirectory}) {
@@ -619,7 +698,19 @@ class ErrorHandlingProcessManager extends ProcessManager {
     Encoding stdoutEncoding = io.systemEncoding,
     Encoding stderrEncoding = io.systemEncoding,
   }) {
-    return _run(() => _delegate.run(
+    return _run(() {
+      if (_skipCommandLookup && _delegate is LocalProcessManager) {
+       return _processDelegate.run(
+          command.cast<String>(),
+          workingDirectory: workingDirectory,
+          environment: environment,
+          includeParentEnvironment: includeParentEnvironment,
+          runInShell: runInShell,
+          stdoutEncoding: stdoutEncoding,
+          stderrEncoding: stderrEncoding,
+        );
+      }
+      return _delegate.run(
         command,
         workingDirectory: workingDirectory,
         environment: environment,
@@ -627,7 +718,8 @@ class ErrorHandlingProcessManager extends ProcessManager {
         runInShell: runInShell,
         stdoutEncoding: stdoutEncoding,
         stderrEncoding: stderrEncoding,
-    ), platform: _platform);
+      );
+    }, platform: _platform);
   }
 
   @override
@@ -639,13 +731,24 @@ class ErrorHandlingProcessManager extends ProcessManager {
     bool runInShell = false,
     io.ProcessStartMode mode = io.ProcessStartMode.normal,
   }) {
-    return _run(() => _delegate.start(
+    return _run(() {
+      if (_skipCommandLookup && _delegate is LocalProcessManager) {
+        return _processDelegate.start(
+          command.cast<String>(),
+          workingDirectory: workingDirectory,
+          environment: environment,
+          includeParentEnvironment: includeParentEnvironment,
+          runInShell: runInShell,
+        );
+      }
+      return _delegate.start(
         command,
         workingDirectory: workingDirectory,
         environment: environment,
         includeParentEnvironment: includeParentEnvironment,
         runInShell: runInShell,
-    ), platform: _platform);
+      );
+    }, platform: _platform);
   }
 
   @override
@@ -658,7 +761,19 @@ class ErrorHandlingProcessManager extends ProcessManager {
     Encoding stdoutEncoding = io.systemEncoding,
     Encoding stderrEncoding = io.systemEncoding,
   }) {
-    return _runSync(() => _delegate.runSync(
+    return _runSync(() {
+      if (_skipCommandLookup && _delegate is LocalProcessManager) {
+        return _processDelegate.runSync(
+          command.cast<String>(),
+          workingDirectory: workingDirectory,
+          environment: environment,
+          includeParentEnvironment: includeParentEnvironment,
+          runInShell: runInShell,
+          stdoutEncoding: stdoutEncoding,
+          stderrEncoding: stderrEncoding,
+        );
+      }
+      return _delegate.runSync(
         command,
         workingDirectory: workingDirectory,
         environment: environment,
@@ -666,7 +781,8 @@ class ErrorHandlingProcessManager extends ProcessManager {
         runInShell: runInShell,
         stdoutEncoding: stdoutEncoding,
         stderrEncoding: stderrEncoding,
-    ), platform: _platform);
+      );
+    }, platform: _platform);
   }
 }
 

packages/flutter_tools/lib/src/dart/pub.dart

@@ -4,7 +4,6 @@
 
 // @dart = 2.8
 
-
 import 'package:meta/meta.dart';
 import 'package:package_config/package_config.dart';
 import 'package:process/process.dart';
@@ -12,6 +11,7 @@ import 'package:process/process.dart';
 import '../base/bot_detector.dart';
 import '../base/common.dart';
 import '../base/context.dart';
+import '../base/error_handling_io.dart';
 import '../base/file_system.dart';
 import '../base/io.dart' as io;
 import '../base/logger.dart';
@@ -333,11 +333,14 @@ class _DefaultPub implements Pub {
     bool touchesPackageConfig = false,
     bool generateSyntheticPackage = false,
   }) async {
-    final io.Process process = await _processUtils.start(
+    // Fully resolved pub or pub.bat is calculated based on current platform.
+    final io.Process process = await ErrorHandlingProcessManager.skipCommandLookup(() async {
+      return _processUtils.start(
         _pubCommand(arguments),
         workingDirectory: directory,
         environment: await _createPubEnvironment(PubContext.interactive),
       );
+    });
 
     // Pipe the Flutter tool stdin to the pub stdin.
     unawaited(process.stdin.addStream(stdio.stdin)

packages/flutter_tools/test/general.shard/base/error_handling_io_test.dart

@@ -15,6 +15,7 @@ import 'package:flutter_tools/src/globals.dart' as globals show flutterUsage;
 import 'package:flutter_tools/src/reporting/reporting.dart';
 import 'package:mockito/mockito.dart';
 import 'package:path/path.dart' as path; // ignore: package_path_import
+import 'package:process/process.dart';
 
 import '../../src/common.dart';
 import '../../src/context.dart';
@@ -669,6 +670,25 @@ void main() {
     });
   });
 
+  test('skipCommandLookup invokes Process calls directly', () async {
+    final ErrorHandlingProcessManager processManager = ErrorHandlingProcessManager(
+      delegate: const LocalProcessManager(),
+      platform: windowsPlatform,
+    );
+
+    // Throws an argument error because package:process fails to locate the executable.
+    expect(() => processManager.runSync(<String>['foo']), throwsArgumentError);
+    expect(() => processManager.run(<String>['foo']), throwsArgumentError);
+    expect(() => processManager.start(<String>['foo']), throwsArgumentError);
+
+    // Throws process exception because the executable does not exist.
+    await ErrorHandlingProcessManager.skipCommandLookup<void>(() async {
+      expect(() => processManager.runSync(<String>['foo']), throwsA(isA<ProcessException>()));
+      expect(() => processManager.run(<String>['foo']), throwsA(isA<ProcessException>()));
+      expect(() => processManager.start(<String>['foo']), throwsA(isA<ProcessException>()));
+    });
+  });
+
   group('ProcessManager on windows throws tool exit', () {
     const int kDeviceFull = 112;
     const int kUserMappedSectionOpened = 1224;