Check for mandatory when using option

pkgs/args/CHANGELOG.md

@@ -1,10 +1,11 @@
-## 2.6.1-wip
+## 2.7.0
 
 * Remove sorting of the `allowedHelp` argument in usage output. Ordering will
   depend on key order for the passed `Map`.
 * Fix the repository URL in `pubspec.yaml`.
 * Added option `hideNegatedUsage` to `ArgParser.flag()` allowing a flag to be
   `negatable` without showing it in the usage text.
+* Fixed #101, adding check for mandatory when using `.option()`.
 
 ## 2.6.0
 

pkgs/args/lib/src/arg_results.dart

@@ -81,9 +81,9 @@ class ArgResults {
   ///
   /// [name] must be a valid flag name in the parser.
   bool flag(String name) {
-    var option = _parser.options[name];
+    final option = _parser.options[name];
     if (option == null) {
-      throw ArgumentError('Could not find an option named "--$name".');
+      throw ArgumentError('Could not find a flag named "--$name".');
     }
     if (!option.isFlag) {
       throw ArgumentError('"$name" is not a flag.');
@@ -95,13 +95,16 @@ class ArgResults {
   ///
   /// [name] must be a valid option name in the parser.
   String? option(String name) {
-    var option = _parser.options[name];
+    final option = _parser.options[name];
     if (option == null) {
       throw ArgumentError('Could not find an option named "--$name".');
     }
     if (!option.isSingle) {
       throw ArgumentError('"$name" is a multi-option.');
     }
+    if (option.mandatory && !_parsed.containsKey(name)) {
+      throw ArgumentError('Option $name is mandatory.');
+    }
     return option.valueOrDefault(_parsed[name]) as String?;
   }
 

pkgs/args/pubspec.yaml

@@ -1,5 +1,5 @@
 name: args
-version: 2.6.1-wip
+version: 2.7.0
 description: >-
   Library for defining parsers for parsing raw command-line arguments into a set
   of options and values using GNU and POSIX style options.

pkgs/args/test/parse_test.dart

@@ -621,6 +621,7 @@ void main() {
           var results = parser.parse(['-h']);
           expect(results['help'], true);
           expect(() => results['test'], throwsA(isA<ArgumentError>()));
+          expect(() => results.option('test'), throwsA(isA<ArgumentError>()));
         });
       });
     });