[flutter_tools] catch StdinException when setting terminal to SingleCharMode (#136283)

Fixes https://github.com/flutter/flutter/issues/129198

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

@@ -314,13 +314,19 @@ class AnsiTerminal implements Terminal {
       return;
     }
     final io.Stdin stdin = _stdio.stdin as io.Stdin;
-    // The order of setting lineMode and echoMode is important on Windows.
-    if (value) {
-      stdin.echoMode = false;
-      stdin.lineMode = false;
-    } else {
-      stdin.lineMode = true;
-      stdin.echoMode = true;
+
+    try {
+      // The order of setting lineMode and echoMode is important on Windows.
+      if (value) {
+        stdin.echoMode = false;
+        stdin.lineMode = false;
+      } else {
+        stdin.lineMode = true;
+        stdin.echoMode = true;
+      }
+    } on io.StdinException {
+      // If the pipe to STDIN has been closed it's probably because the
+      // terminal has been closed, and there is nothing actionable to do here.
     }
   }
 

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

@@ -9,6 +9,7 @@ import 'package:flutter_tools/src/base/terminal.dart';
 import 'package:test/fake.dart';
 
 import '../../src/common.dart';
+import '../../src/fakes.dart';
 
 void main() {
   group('output preferences', () {
@@ -253,6 +254,16 @@ void main() {
     expect(AnsiTerminal(stdio: stdio, platform: const LocalPlatform(), now: DateTime(2018, 1, 10, 23)).preferredStyle, 2);
     expect(AnsiTerminal(stdio: stdio, platform: const LocalPlatform(), now: DateTime(2018, 1, 11, 23)).preferredStyle, 3);
   });
+
+  testWithoutContext('set singleCharMode resilient to StdinException', () async {
+    final FakeStdio stdio = FakeStdio();
+    final AnsiTerminal terminal = AnsiTerminal(stdio: stdio, platform: const LocalPlatform());
+    stdio.stdinHasTerminal = true;
+    stdio._stdin = FakeStdin()..echoModeCallback = (bool _) => throw const StdinException(
+      'Error setting terminal echo mode, OS Error: The handle is invalid.',
+    );
+    terminal.singleCharMode = true;
+  });
 }
 
 late Stream<String> mockStdInStream;
@@ -269,14 +280,36 @@ class TestTerminal extends AnsiTerminal {
     return mockStdInStream;
   }
 
+  bool _singleCharMode = false;
+
   @override
-  bool singleCharMode = false;
+  bool get singleCharMode => _singleCharMode;
+
+  void Function(bool newMode)? _singleCharModeCallback;
+
+  @override
+  set singleCharMode(bool newMode) {
+    _singleCharMode = newMode;
+    if (_singleCharModeCallback != null) {
+      _singleCharModeCallback!(newMode);
+    }
+  }
 
   @override
   int get preferredStyle => 0;
 }
 
 class FakeStdio extends Fake implements Stdio {
+  Stream<List<int>>? _stdin;
+
+  @override
+  Stream<List<int>> get stdin {
+    if (_stdin != null) {
+      return _stdin!;
+    }
+    throw UnimplementedError('stdin');
+  }
+
   @override
   bool stdinHasTerminal = false;
 }

packages/flutter_tools/test/src/fakes.dart

@@ -253,8 +253,20 @@ class FakeStdio extends Stdio {
 class FakeStdin extends Fake implements Stdin {
   final StreamController<List<int>> controller = StreamController<List<int>>();
 
+  void Function(bool mode)? echoModeCallback;
+
+  bool _echoMode = true;
+
   @override
-  bool echoMode = true;
+  bool get echoMode => _echoMode;
+
+  @override
+  set echoMode(bool mode) {
+    _echoMode = mode;
+    if (echoModeCallback != null) {
+      echoModeCallback!(mode);
+    }
+  }
 
   @override
   bool lineMode = true;