Revert "[pkg/dart2native] upgrade dart2native to null safe"

This reverts commit b6fad9c4f3.

Reason for revert: Seeing failures in google3.

Original change's description:
> [pkg/dart2native] upgrade dart2native to null safe
>
> Change-Id: Ieef99b982bab14425a4df9f84a40d8ae1ba2bd79
> Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/202402
> Reviewed-by: Ben Konyi <bkonyi@google.com>
> Commit-Queue: Devon Carew <devoncarew@google.com>

TBR=devoncarew@google.com,bkonyi@google.com

Change-Id: Idff233978847be421f7b59ab93d04da99c02cbf5
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/202722
Reviewed-by: Devon Carew <devoncarew@google.com>
Commit-Queue: Devon Carew <devoncarew@google.com>

.dart_tool/package_config.json

@@ -214,7 +214,7 @@
       "name": "dart2native",
       "rootUri": "../pkg/dart2native",
       "packageUri": "lib/",
-      "languageVersion": "2.12"
+      "languageVersion": "2.7"
     },
     {
       "name": "dart_internal",

pkg/dart2native/analysis_options.yaml

@@ -1,4 +1,10 @@
-include: package:lints/recommended.yaml
+include: package:pedantic/analysis_options.1.8.0.yaml
+
+analyzer:
+  errors:
+    # Increase the severity of several hints.
+    prefer_single_quotes: warning
+    unused_import: warning
 
 linter:
   rules:

pkg/dart2native/bin/dart2native.dart

@@ -21,12 +21,10 @@ Generates an executable or an AOT snapshot from <main-dart-file>.
 
 Future<void> main(List<String> args) async {
   // If we're outputting to a terminal, wrap usage text to that width.
-  int? outputLineWidth;
+  int outputLineWidth;
   try {
     outputLineWidth = stdout.terminalColumns;
-  } catch (_) {
-    /* Ignore. */
-  }
+  } catch (_) {/* Ignore. */}
 
   final ArgParser parser = ArgParser(usageLineLength: outputLineWidth)
     ..addMultiOption('define', abbr: 'D', valueHelp: 'key=value', help: '''
@@ -105,7 +103,7 @@ Sets the verbosity level used for filtering messages during compilation.
   final String sourceFile = parsedArgs.rest[0];
   if (!FileSystemEntity.isFileSync(sourceFile)) {
     stderr.writeln(
-        '"$sourceFile" is not a file. See \'--help\' for more information.');
+        '"${sourceFile}" is not a file. See \'--help\' for more information.');
     await stderr.flush();
     exit(1);
   }
@@ -117,7 +115,7 @@ Sets the verbosity level used for filtering messages during compilation.
         outputFile: parsedArgs['output'],
         debugFile: parsedArgs['save-debugging-info'],
         packages: parsedArgs['packages'],
-        defines: parsedArgs['define'] ?? [],
+        defines: parsedArgs['define'],
         enableExperiment: parsedArgs['enable-experiment'],
         enableAsserts: parsedArgs['enable-asserts'],
         soundNullSafety: parsedArgs['sound-null-safety'],

pkg/dart2native/lib/dart2native.dart

@@ -44,7 +44,7 @@ Future<ProcessResult> generateAotKernel(
     String platformDill,
     String sourceFile,
     String kernelFile,
-    String? packages,
+    String packages,
     List<String> defines,
     {String enableExperiment = '',
     List<String> extraGenKernelOptions = const []}) {
@@ -52,10 +52,10 @@ Future<ProcessResult> generateAotKernel(
     genKernel,
     '--platform',
     platformDill,
-    if (enableExperiment.isNotEmpty) '--enable-experiment=$enableExperiment',
+    if (enableExperiment.isNotEmpty) '--enable-experiment=${enableExperiment}',
     '--aot',
     '-Ddart.vm.product=true',
-    ...(defines.map((d) => '-D$d')),
+    ...(defines.map((d) => '-D${d}')),
     if (packages != null) ...['--packages', packages],
     '-o',
     kernelFile,
@@ -65,16 +65,15 @@ Future<ProcessResult> generateAotKernel(
 }
 
 Future generateAotSnapshot(
-  String genSnapshot,
-  String kernelFile,
-  String snapshotFile,
-  bool enableAsserts,
-  List<String> extraGenSnapshotOptions, {
-  String? debugFile,
-}) {
+    String genSnapshot,
+    String kernelFile,
+    String snapshotFile,
+    String debugFile,
+    bool enableAsserts,
+    List<String> extraGenSnapshotOptions) {
   return Process.run(genSnapshot, [
     '--snapshot-kind=app-aot-elf',
-    '--elf=$snapshotFile',
+    '--elf=${snapshotFile}',
     if (debugFile != null) '--save-debugging-info=$debugFile',
     if (debugFile != null) '--dwarf-stack-traces',
     if (debugFile != null) '--strip',

pkg/dart2native/lib/generate.dart

@@ -3,32 +3,30 @@
 // BSD-style license that can be found in the LICENSE file.
 
 import 'dart:io';
-
 import 'package:path/path.dart' as path;
-
 import 'dart2native.dart';
 
 final Directory binDir = File(Platform.resolvedExecutable).parent;
 final String executableSuffix = Platform.isWindows ? '.exe' : '';
 final String dartaotruntime =
-    path.join(binDir.path, 'dartaotruntime$executableSuffix');
+    path.join(binDir.path, 'dartaotruntime${executableSuffix}');
 final String genKernel =
     path.join(binDir.path, 'snapshots', 'gen_kernel.dart.snapshot');
 final String genSnapshot =
-    path.join(binDir.path, 'utils', 'gen_snapshot$executableSuffix');
+    path.join(binDir.path, 'utils', 'gen_snapshot${executableSuffix}');
 final String productPlatformDill = path.join(
     binDir.parent.path, 'lib', '_internal', 'vm_platform_strong_product.dill');
 
 Future<void> generateNative({
   String kind = 'exe',
-  required String sourceFile,
-  String? outputFile,
-  String? debugFile,
-  String? packages,
-  required List<String> defines,
+  String sourceFile,
+  String outputFile,
+  String debugFile,
+  String packages,
+  List<String> defines,
   String enableExperiment = '',
   bool enableAsserts = false,
-  bool? soundNullSafety,
+  bool soundNullSafety,
   bool verbose = false,
   String verbosity = 'all',
   List<String> extraOptions = const [],
@@ -39,13 +37,17 @@ Future<void> generateNative({
     if (packages != null) {
       packages = path.canonicalize(path.normalize(packages));
     }
-    final Kind outputKind = {'aot': Kind.aot, 'exe': Kind.exe}[kind]!;
+    final Kind outputKind = {
+      'aot': Kind.aot,
+      'exe': Kind.exe,
+    }[kind];
     final sourceWithoutDart = sourcePath.replaceFirst(RegExp(r'\.dart$'), '');
-    final outputPath = path.canonicalize(path.normalize(outputFile ??
-        {
-          Kind.aot: '$sourceWithoutDart.aot',
-          Kind.exe: '$sourceWithoutDart.exe',
-        }[outputKind]!));
+    final outputPath = path.canonicalize(path.normalize(outputFile != null
+        ? outputFile
+        : {
+            Kind.aot: '${sourceWithoutDart}.aot',
+            Kind.exe: '${sourceWithoutDart}.exe',
+          }[outputKind]));
     final debugPath =
         debugFile != null ? path.canonicalize(path.normalize(debugFile)) : null;
 
@@ -88,14 +90,8 @@ Future<void> generateNative({
     final String snapshotFile = (outputKind == Kind.aot
         ? outputPath
         : path.join(tempDir.path, 'snapshot.aot'));
-    final snapshotResult = await generateAotSnapshot(
-      genSnapshot,
-      kernelFile,
-      snapshotFile,
-      enableAsserts,
-      extraOptions,
-      debugFile: debugPath,
-    );
+    final snapshotResult = await generateAotSnapshot(genSnapshot, kernelFile,
+        snapshotFile, debugPath, enableAsserts, extraOptions);
     if (snapshotResult.exitCode != 0) {
       stderr.writeln(snapshotResult.stdout);
       stderr.writeln(snapshotResult.stderr);
@@ -117,7 +113,7 @@ Future<void> generateNative({
       }
     }
 
-    print('Generated: $outputPath');
+    print('Generated: ${outputPath}');
   } finally {
     tempDir.deleteSync(recursive: true);
   }

pkg/dart2native/pubspec.yaml

@@ -3,7 +3,7 @@ name: dart2native
 publish_to: none
 
 environment:
-  sdk: '>=2.12.0 <3.0.0'
+  sdk: "^2.7.0"
 
 # Add the bin/dart2native.dart script to the scripts pub installs.
 executables:
@@ -16,4 +16,3 @@ dependencies:
      path: ../front_end
 
 dev_dependencies:
-  lints: ^1.0.0