Check for bad characters in path on Windows build (#107949)

* Check for bad characters in path on Windows build

* Doc comments

* Fix formatting

* Commenting/formatting

* Link to issue in comment

* Comments, formatting

* Global var rename

packages/flutter_tools/lib/src/windows/build_windows.dart

@@ -19,12 +19,29 @@ import '../globals.dart' as globals;
 import '../migrations/cmake_custom_command_migration.dart';
 import 'visual_studio.dart';
 
+// These characters appear to be fine: @%()-+_{}[]`~
+const String _kBadCharacters = r"'#!$^&*=|,;<>?";
+
 /// Builds the Windows project using msbuild.
 Future<void> buildWindows(WindowsProject windowsProject, BuildInfo buildInfo, {
   String? target,
   VisualStudio? visualStudioOverride,
   SizeAnalyzer? sizeAnalyzer,
 }) async {
+  // MSBuild files generated by CMake do not properly escape some characters
+  // In the directories. This check produces more meaningful error messages
+  // on failure as pertains to https://github.com/flutter/flutter/issues/104802
+  final String projectPath = windowsProject.parent.directory.absolute.path;
+  final bool badPath = _kBadCharacters.runes
+      .any((int i) => projectPath.contains(String.fromCharCode(i)));
+  if (badPath) {
+    throwToolExit(
+      'Path $projectPath contains invalid characters in "$_kBadCharacters". '
+      'Please rename your directory so as to not include any of these characters '
+      'and retry.',
+    );
+  }
+
   if (!windowsProject.cmakeFile.existsSync()) {
     throwToolExit(
       'No Windows desktop project configured. See '

packages/flutter_tools/test/commands.shard/hermetic/build_windows_test.dart

@@ -21,9 +21,11 @@ import '../../src/fakes.dart';
 import '../../src/test_flutter_command_runner.dart';
 
 const String flutterRoot = r'C:\flutter';
-const String buildFilePath = r'C:\windows\CMakeLists.txt';
+const String buildFilePath = r'windows\CMakeLists.txt';
-const String visualStudioPath = r'C:\Program Files (x86)\Microsoft Visual Studio\2017\Community';
+const String visualStudioPath =
-const String _cmakePath = visualStudioPath + r'\Common7\IDE\CommonExtensions\Microsoft\CMake\CMake\bin\cmake.exe';
+    r'C:\Program Files (x86)\Microsoft Visual Studio\2017\Community';
+const String _cmakePath = visualStudioPath +
+    r'\Common7\IDE\CommonExtensions\Microsoft\CMake\CMake\bin\cmake.exe';
 const String _defaultGenerator = 'Visual Studio 16 2019';
 
 final Platform windowsPlatform = FakePlatform(
@@ -80,7 +82,7 @@ void main() {
       command: <String>[
         _cmakePath,
         '-S',
-        fileSystem.path.dirname(buildFilePath),
+        fileSystem.path.absolute(fileSystem.path.dirname(buildFilePath)),
         '-B',
         r'build\windows',
         '-G',
@@ -933,6 +935,35 @@ if %errorlevel% neq 0 goto :VCEnd</Command>
     FileSystemUtils: () => FileSystemUtils(fileSystem: fileSystem, platform: windowsPlatform),
     Usage: () => usage,
   });
+
+  // Confirms that running for Windows in a directory with a
+  // bad character (' in this case) throws the desired error message
+  // If the issue https://github.com/flutter/flutter/issues/104802 ever
+  // is resolved on the VS side, we can allow these paths again
+  testUsingContext('Test bad path characters', () async {
+    final FakeVisualStudio fakeVisualStudio = FakeVisualStudio();
+    final BuildWindowsCommand command = BuildWindowsCommand()
+      ..visualStudioOverride = fakeVisualStudio;
+    fileSystem.currentDirectory = fileSystem.directory("test_'path")
+      ..createSync();
+    final String absPath = fileSystem.currentDirectory.absolute.path;
+    setUpMockCoreProjectFiles();
+
+    expect(
+        createTestCommandRunner(command).run(const <String>['windows', '--no-pub']),
+        throwsToolExit(
+          message:
+              'Path $absPath contains invalid characters in "\'#!\$^&*=|,;<>?". '
+              'Please rename your directory so as to not include any of these characters '
+              'and retry.',
+        ),
+    );
+  }, overrides: <Type, Generator>{
+    Platform: () => windowsPlatform,
+    FileSystem: () => fileSystem,
+    ProcessManager: () => FakeProcessManager.any(),
+    FeatureFlags: () => TestFeatureFlags(isWindowsEnabled: true),
+  });
 }
 
 class FakeVisualStudio extends Fake implements VisualStudio {