Fix short flag parsing to strip equals sign from value

pkgs/args/lib/src/parser.dart

@@ -207,6 +207,11 @@ class Parser {
       // The first character is a non-flag option, so the rest must be the
       // value.
       var value = '${lettersAndDigits.substring(1)}$rest';
+      // If the value starts with '=' (like in -o=value), strip it to match
+      // the behavior of long options (--option=value).
+      if (value.startsWith('=')) {
+        value = value.substring(1);
+      }
       _setOption(_results, first, value, '-$c');
     } else {
       // If we got some non-flag characters, then it must be a value, but

pkgs/args/test/short_flag_equals_test.dart

@@ -0,0 +1,64 @@
+import 'package:args/args.dart';
+import 'package:test/test.dart';
+
+void main() {
+  group('Short flag with equals syntax', () {
+    test('should parse value correctly without including equals sign', () {
+      final parser = ArgParser();
+      parser.addOption('option', abbr: 'o');
+
+      // Test long flag with equals
+      final result1 = parser.parse(['--option=value']);
+      expect(result1['option'], equals('value'));
+
+      // Test short flag with equals - currently fails
+      final result2 = parser.parse(['-o=value']);
+      expect(result2['option'], equals('value')); // Currently gets '=value'
+
+      // Test short flag with space (this works correctly)
+      final result3 = parser.parse(['-o', 'value']);
+      expect(result3['option'], equals('value'));
+
+      // All three should produce the same result
+      expect(result1['option'], equals(result2['option']));
+      expect(result2['option'], equals(result3['option']));
+    });
+
+    test('should handle complex values with equals', () {
+      final parser = ArgParser();
+      parser.addOption('config', abbr: 'c');
+
+      final result1 = parser.parse(['--config=key=value']);
+      final result2 = parser.parse(['-c=key=value']);
+
+      expect(result1['config'], equals('key=value'));
+      expect(result2['config'],
+          equals('key=value')); // Currently gets '=key=value'
+    });
+
+    test('should handle empty value after equals', () {
+      final parser = ArgParser();
+      parser.addOption('value', abbr: 'v');
+
+      final result1 = parser.parse(['--value=']);
+      final result2 = parser.parse(['-v=']);
+
+      expect(result1['value'], equals(''));
+      expect(result2['value'], equals('')); // Currently gets '='
+    });
+
+    test('should work with real-world example (bundle ID)', () {
+      final parser = ArgParser();
+      parser.addOption('ios-bundle-id', abbr: 'i');
+
+      final bundleId = 'com.example.app';
+
+      final result1 = parser.parse(['--ios-bundle-id=$bundleId']);
+      final result2 = parser.parse(['-i=$bundleId']);
+
+      expect(result1['ios-bundle-id'], equals(bundleId));
+      expect(result2['ios-bundle-id'],
+          equals(bundleId)); // Currently gets '=com.example.app'
+    });
+  });
+}