[package:args] Added offset argument when throwing a ArgParserException.

pkgs/args/CHANGELOG.md

@@ -1,6 +1,7 @@
 ## 2.6.1-wip
 
 * Fix the reporitory URL in `pubspec.yaml`.
+* Added offset argument when throwing a `ArgParserException`.
 
 ## 2.6.0
 

pkgs/args/lib/src/allow_anything_parser.dart

@@ -2,8 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-import 'dart:collection';
-
 import 'arg_parser.dart';
 import 'arg_results.dart';
 import 'option.dart';
@@ -83,7 +81,7 @@ class AllowAnythingParser implements ArgParser {
 
   @override
   ArgResults parse(Iterable<String> args) =>
-      Parser(null, this, Queue.of(args)).parse();
+      Parser(null, this, ArgsQueue(args)).parse();
 
   @override
   String get usage => '';

pkgs/args/lib/src/arg_parser.dart

@@ -331,7 +331,7 @@ class ArgParser {
   /// Parses [args], a list of command-line arguments, matches them against the
   /// flags and options defined by this parser, and returns the result.
   ArgResults parse(Iterable<String> args) =>
-      Parser(null, this, Queue.of(args)).parse();
+      Parser(null, this, ArgsQueue(args)).parse();
 
   /// Generates a string displaying usage information for the defined options.
   ///

pkgs/args/lib/src/arg_parser_exception.dart

@@ -19,4 +19,10 @@ class ArgParserException extends FormatException {
       super.source,
       super.offset])
       : commands = commands == null ? const [] : List.unmodifiable(commands);
+
+  /// Returns a string representation of this exception.
+  @override
+  String toString() {
+    return 'FormatException: $message';
+  }
 }

pkgs/args/lib/src/parser.dart

@@ -2,13 +2,54 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-import 'dart:collection';
-
 import 'arg_parser.dart';
 import 'arg_parser_exception.dart';
 import 'arg_results.dart';
 import 'option.dart';
 
+/// A queue of arguments that can be removed from the front.
+/// This is used to keep track of the arguments that have been parsed.
+class ArgsQueue<T> {
+  /// The arguments to be parsed.
+  final Iterable<T> _args;
+
+  /// The index of the next argument to be parsed.
+  int _index = 0;
+
+  /// Creates a new queue of arguments.
+  ArgsQueue(this._args);
+
+  /// The source of the arguments.
+  Iterable<T> get args => _args;
+
+  /// The current index of the queue.
+  int get index => _index;
+
+  /// The number of arguments in the queue.
+  bool get isEmpty => _index >= _args.length;
+
+  /// The number of arguments in the queue.
+  bool get isNotEmpty => _index < _args.length;
+
+  /// The first argument in the queue.
+  T get first => _args.elementAt(_index);
+
+  /// Removes the first argument from the queue.
+  T removeFirst() {
+    return _args.elementAt(_index++);
+  }
+
+  /// Returns the remaining arguments in the queue.
+  List<T> toList() {
+    return _args.skip(_index).toList();
+  }
+
+  /// Clears the queue.
+  void clear() {
+    _index = _args.length;
+  }
+}
+
 /// The actual argument parsing class.
 ///
 /// Unlike [ArgParser] which is really more an "arg grammar", this is the class
@@ -26,7 +67,7 @@ class Parser {
   final ArgParser _grammar;
 
   /// The arguments being parsed.
-  final Queue<String> _args;
+  final ArgsQueue<String> _args;
 
   /// The remaining non-option, non-command arguments.
   final List<String> _rest;
@@ -114,7 +155,7 @@ class Parser {
     });
 
     // Add in the leftover arguments we didn't parse to the innermost command.
-    _rest.addAll(_args);
+    _rest.addAll(_args.toList());
     _args.clear();
     return newArgResults(
         _grammar, _results, _commandName, commandResults, _rest, arguments);
@@ -274,17 +315,19 @@ class Parser {
   bool _handleLongOption(String name, String? value) {
     var option = _grammar.findByNameOrAlias(name);
     if (option != null) {
-      _args.removeFirst();
       if (option.isFlag) {
         _validate(value == null,
             'Flag option "--$name" should not be given a value.', '--$name');
 
+        _args.removeFirst();
         _setFlag(_results, option, true);
       } else if (value != null) {
         // We have a value like --foo=bar.
+        _args.removeFirst();
         _setOption(_results, option, value, '--$name');
       } else {
         // Option like --foo, so look for the value as the next arg.
+        _args.removeFirst();
         _readNextArgAsValue(option, '--$name');
       }
     } else if (name.startsWith('no-')) {
@@ -318,10 +361,9 @@ class Parser {
   /// Called during parsing to validate the arguments.
   ///
   /// Throws an [ArgParserException] if [condition] is `false`.
-  void _validate(bool condition, String message,
-      [String? args, List<String>? source, int? offset]) {
+  void _validate(bool condition, String message, [String? args]) {
     if (!condition) {
-      throw ArgParserException(message, null, args, source, offset);
+      throw ArgParserException(message, null, args, _args.args, _args.index);
     }
   }
 

pkgs/args/test/parse_test.dart

@@ -771,18 +771,23 @@ void main() {
       test('throws exception for unknown option', () {
         var parser = ArgParser();
         throwsArgParserException(parser, ['--verbose'],
-            'Could not find an option named "--verbose".', [], '--verbose');
-        throwsArgParserException(
-            parser, ['-v'], 'Could not find an option or flag "-v".', [], '-v');
+            'Could not find an option named "--verbose".', [], '--verbose', 0);
+        throwsArgParserException(parser, ['-v'],
+            'Could not find an option or flag "-v".', [], '-v', 0);
       });
 
       test('throws exception for flag with value', () {
         var parser = ArgParser();
         parser.addFlag('flag', abbr: 'f');
-        throwsArgParserException(parser, ['--flag=1'],
-            'Flag option "--flag" should not be given a value.', [], '--flag');
+        throwsArgParserException(
+            parser,
+            ['--flag=1'],
+            'Flag option "--flag" should not be given a value.',
+            [],
+            '--flag',
+            0);
         throwsArgParserException(parser, ['-f=1'],
-            'Option "-f" is a flag and cannot handle value "=1".', [], '-f');
+            'Option "-f" is a flag and cannot handle value "=1".', [], '-f', 0);
       });
 
       test('throws exception after parsing multiple options', () {
@@ -794,14 +799,20 @@ void main() {
             ['--first', '1', '--second', '2', '--verbose', '3'],
             'Could not find an option named "--verbose".',
             [],
-            '--verbose');
+            '--verbose',
+            4);
       });
 
       test('throws exception for option with invalid value', () {
         var parser = ArgParser();
         parser.addOption('first', allowed: ['a', 'b']);
-        throwsArgParserException(parser, ['--first', 'c'],
-            '"c" is not an allowed value for option "--first".', [], '--first');
+        throwsArgParserException(
+            parser,
+            ['--first', 'c'],
+            '"c" is not an allowed value for option "--first".',
+            [],
+            '--first',
+            1);
       });
 
       test('throws exception after parsing command', () {
@@ -812,7 +823,8 @@ void main() {
             ['command', '--verbose'],
             'Could not find an option named "--verbose".',
             ['command'],
-            '--verbose');
+            '--verbose',
+            1);
       });
     });
   });

pkgs/args/test/test_utils.dart

@@ -349,14 +349,16 @@ void throwsFormat(ArgParser parser, List<String> args, {String? reason}) {
 }
 
 void throwsArgParserException(ArgParser parser, List<String> args,
-    String message, List<String> commands, String arg) {
+    String message, List<String> commands, String argumentName, int offset) {
   try {
     parser.parse(args);
     fail('Expected an ArgParserException');
   } on ArgParserException catch (e) {
     expect(e.message, message);
     expect(e.commands, commands);
-    expect(e.argumentName, arg);
+    expect(e.argumentName, argumentName);
+    expect(e.source, args);
+    expect(e.offset, offset);
   } catch (e) {
     fail('Expected an ArgParserException, but got $e');
   }