Fixed a bug in argument handling

2 files changed, 12 insertions, 1 deletions

diff --git a/click/core.py b/click/core.py
index c0a17f4..e64e57c 100644
--- a/click/core.py
+++ b/click/core.py
@@ -1173,7 +1173,7 @@ class Argument(Parameter):
             if attrs.get('default') is not None:
                 required = False
             else:
-                required = attrs.get('nargs', 0) > 0
+                required = attrs.get('nargs', 1) > 0
         Parameter.__init__(self, param_decls, required=required, **attrs)
 
     def make_metavar(self):
diff --git a/tests/test_arguments.py b/tests/test_arguments.py
index 681c5b9..3f936ed 100644
--- a/tests/test_arguments.py
+++ b/tests/test_arguments.py
@@ -145,6 +145,17 @@ def test_empty_nargs(runner):
     assert 'Missing argument "arg"' in result.output
 
 
+def test_missing_arg(runner):
+    @click.command()
+    @click.argument('arg')
+    def cmd(arg):
+        click.echo('arg:' + arg)
+
+    result = runner.invoke(cmd, [])
+    assert result.exit_code == 2
+    assert 'Missing argument "arg".' in result.output
+
+
 def test_implicit_non_required(runner):
     @click.command()
     @click.argument('f', default='test')