From: R David Murray <rdmurray@bitdance.com>
Date: Sat, 8 Sep 2012 16:15:25 +0000 (-0400)
Subject: #15847: allow args to be a tuple in parse_args
X-Git-Tag: v2.7.5~109^2~331
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=a99c7dedcb9310d80f2cf29a747e05fdde2716bc;p=python

#15847: allow args to be a tuple in parse_args

This fixes a regression introduced by the fix for issue #13922.  Although args
is not documented as being allowed to be a tuple, previously this worked and
so naturally there are programs in the field that depend on it.

Patch by Zbyszek Jędrzejewski-Szmek.
---

diff --git a/Lib/argparse.py b/Lib/argparse.py
index a73845594f..ab8ff2faec 100644
--- a/Lib/argparse.py
+++ b/Lib/argparse.py
@@ -1692,9 +1692,12 @@ class ArgumentParser(_AttributeHolder, _ActionsContainer):
         return args
 
     def parse_known_args(self, args=None, namespace=None):
-        # args default to the system args
         if args is None:
+            # args default to the system args
             args = _sys.argv[1:]
+        else:
+            # make sure that args are mutable
+            args = list(args)
 
         # default Namespace built from parser defaults
         if namespace is None:
diff --git a/Lib/test/test_argparse.py b/Lib/test/test_argparse.py
index 77f5aca21e..99c1babb4a 100644
--- a/Lib/test/test_argparse.py
+++ b/Lib/test/test_argparse.py
@@ -4486,6 +4486,24 @@ class TestTypeFunctionCallWithNonStringDefault(TestCase):
 
 class TestParseKnownArgs(TestCase):
 
+    def test_arguments_tuple(self):
+        parser = argparse.ArgumentParser()
+        parser.parse_args(())
+
+    def test_arguments_list(self):
+        parser = argparse.ArgumentParser()
+        parser.parse_args([])
+
+    def test_arguments_tuple_positional(self):
+        parser = argparse.ArgumentParser()
+        parser.add_argument('x')
+        parser.parse_args(('x',))
+
+    def test_arguments_list_positional(self):
+        parser = argparse.ArgumentParser()
+        parser.add_argument('x')
+        parser.parse_args(['x'])
+
     def test_optionals(self):
         parser = argparse.ArgumentParser()
         parser.add_argument('--foo')