bpo-37150: Throw ValueError if FileType class object was passed in add_argument (GH-13805)
There is a possibility that someone (like me) accidentally will omit parentheses with `FileType` arguments after `FileType`, and parser will contain wrong file until someone will try to use it.
Example:
```python
parser = argparse.ArgumentParser()
parser.add_argument('-x', type=argparse.FileType)
```
https://bugs.python.org/issue37150
(cherry picked from commit 03d5831a2d62c68654ec223168e574cd546efbf6)
Co-authored-by: zygocephalus <grrrr@protonmail.com>diff --git a/Lib/argparse.py b/Lib/argparse.py
index ef888f0..9a67b41 100644
--- a/Lib/argparse.py
+++ b/Lib/argparse.py
@@ -1361,6 +1361,10 @@
if not callable(type_func):
raise ValueError('%r is not callable' % (type_func,))
+ if type_func is FileType:
+ raise ValueError('%r is a FileType class object, instance of it'
+ ' must be passed' % (type_func,))
+
# raise an error if the metavar does not match the type
if hasattr(self, "_get_formatter"):
try: