[ VM / CLI ] Fix issue where VM flags would be parsed from the option

list for a script.

Fixes #43487

Change-Id: I6f0860e0a43055aaab775a28baa660d60fb1c47e
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/169782
Reviewed-by: Ryan Macnak <[email protected]>
Commit-Queue: Ben Konyi <[email protected]>

Author: bkonyi

pkg/dartdev/lib/dartdev.dart

@@ -89,14 +89,16 @@ Future<void> runDartdev(List<String> args, SendPort port) async {
       args = List.from(args)..remove('--disable-dartdev-analytics');
     }
 
-    // These flags have a format that can't be handled by package:args, so while
-    // they are valid flags we'll assume the VM has verified them by this point.
-    args = args
-        .where(
-          (element) => !(element.contains('--observe') ||
-              element.contains('--enable-vm-service')),
-        )
-        .toList();
+    if (args.contains('run')) {
+      // These flags have a format that can't be handled by package:args, so while
+      // they are valid flags we'll assume the VM has verified them by this point.
+      args = args
+          .where(
+            (element) => !(element.contains('--observe') ||
+                element.contains('--enable-vm-service')),
+          )
+          .toList();
+    }
 
     // If ... help pub ... is in the args list, remove 'help', and add '--help'
     // to the end of the list. This will make it possible to use the help

pkg/dartdev/test/commands/run_test.dart

@@ -221,4 +221,18 @@ void run() {
     expect(result.stderr, contains('Unhandled exception'));
     expect(result.exitCode, 255);
   });
+
+  test('does not interpret VM flags provided after script', () async {
+    p = project(mainSrc: 'void main() { assert(false); }');
+
+    // Any VM flags passed after the script shouldn't be interpreted by the VM.
+    ProcessResult result = p.runSync('run', [
+      p.relativeFilePath,
+      '--enable-asserts',
+    ]);
+
+    expect(result.stdout, isEmpty);
+    expect(result.stderr, isEmpty);
+    expect(result.exitCode, 0);
+  });
 }

runtime/bin/main_options.cc

@@ -599,7 +599,18 @@ int Options::ParseArguments(int argc,
   // dartdev command (e.g., --enable-vm-service, --observe, etc).
   if (!run_script) {
     int tmp_i = i;
+    // We only run the CLI implicitly if the service is enabled and the user
+    // didn't run with the 'run' command. If they did provide a command, we need
+    // to skip it here to continue parsing VM flags.
+    if (!implicitly_use_dart_dev) {
+      tmp_i++;
+    }
     while (tmp_i < argc) {
+      // Check if this flag is a potentially valid VM flag. If not, we've likely
+      // hit a script name and are done parsing VM flags.
+      if (!OptionProcessor::IsValidFlag(argv[tmp_i], kPrefix, kPrefixLen)) {
+        break;
+      }
       OptionProcessor::TryProcess(argv[tmp_i], vm_options);
       tmp_i++;
     }