Repository navigation
Cannot use format specifiers in argparse help #142950
Description
#141940 caused a regression where users cannot use format specifiers.
See this as an example
my_parser.add_argument(
"--foo",
type=int,
default=1234,
help=f"""0x%(default)x""",
)The above works in 3.14.2, but not in 3.15 alpha3. I apologize if my code is doing something incorrect.
The error I get is
Traceback (most recent call last):
File "[...]/3.15.0a3/lib/python3.15/argparse.py", line 1793, in _check_help
formatter._expand_help(action)
~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^
File "[...]/3.15.0a3/lib/python3.15/argparse.py", line 696, in _expand_help
return help_string % params
~~~~~~~~~~~~^~~~~~~~
TypeError: %x format: an integer is required, not strOriginally posted by @oyvindronningstad in #141940 (comment)
Linked PRs
Metadata
Metadata
Assignees
Labels
Projects
- Status
Activity
gitlostmyaccounttt commentedon Dec 18, 2025
%(default)xin help strings #142980 as a duplicate of this issueFix nightly tests (#176)
GH-142950: Process format specifiers before colourization in argparse…
pythonGH-142950: Process format specifiers before colourization in ar…