[pigeon] Recursively create output target files (#4458)

Recursively creates output target files before trying to write to it.

closes #[128820](https://github.com/flutter/flutter/issues/128820)

packages/pigeon/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 10.1.6
+
+* Fixes generation failures when an output file is in a directory that doesn't already exist.
+
 ## 10.1.5
 
 * Fixes import in generated Dart test output when overriding package name.

packages/pigeon/lib/generator_tools.dart

@@ -13,7 +13,7 @@ import 'ast.dart';
 /// The current version of pigeon.
 ///
 /// This must match the version in pubspec.yaml.
-const String pigeonVersion = '10.1.5';
+const String pigeonVersion = '10.1.6';
 
 /// Read all the content from [stdin] to a String.
 String readStdin() {

packages/pigeon/lib/pigeon_lib.dart

@@ -389,6 +389,7 @@ IOSink? _openSink(String? output, {String basePath = ''}) {
     sink = stdout;
   } else {
     file = File(path.posix.join(basePath, output));
+    file.createSync(recursive: true);
     sink = file.openWrite();
   }
   return sink;

packages/pigeon/pubspec.yaml

@@ -2,7 +2,7 @@ name: pigeon
 description: Code generator tool to make communication between Flutter and the host platform type-safe and easier.
 repository: https://github.com/flutter/packages/tree/main/packages/pigeon
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3Apigeon
-version: 10.1.5 # This must match the version in lib/generator_tools.dart
+version: 10.1.6 # This must match the version in lib/generator_tools.dart
 
 environment:
   sdk: ">=2.19.0 <4.0.0"

packages/pigeon/tool/shared/test_suites.dart

@@ -366,6 +366,13 @@ Future<int> _runCommandLineTests() async {
       '--ast_out',
       tempOutput
     ],
+    // Test writing a file in a directory that doesn't exist.
+    <String>[
+      '--input',
+      'pigeons/message.dart',
+      '--dart_out',
+      '$tempDir/subdirectory/does/not/exist/message.g.dart',
+    ],
   ];
 
   int exitCode = 0;