argparse guesses

Print the possible (nearest) value of the argument. If options are specified with thechoices argument.

Pitch

argparse are end user oriented.
Such a message will make the program interface more user-friendly.

defmain():arg_parser=argparse.ArgumentParser()arg_parser.add_argument('family',type=str.casefold,help='Font family',choices=get_all_family_names(FAMILY_FILES))args=arg_parser.parse_args(['S200Flora'])

Now outputs this:

error: argument family: invalid choice: 's200flora' (choose from 'a431', ..., 's200flor', ... 'wingdings 3')

I suggest making the output look like this:

error: argument family: invalid choice: 's200flora',maybe you meant 's200flor'? (choose from 'a431', ..., 's200flor', ... 'wingdings 3')

It doesn't have to look exactly like this. I'm not talking about the implementation, perhaps the assumptions should always be (if there are matches) in the presence of thechoices argument, perhaps only in some certain conditions.
These questions are decided by those who will implement it, as they see fit.

Previous discussion

Add “maybe you meant” in argparsechoices argumenton discuss.python.org

Linked PRs

• gh-99749: Add closest choice if exists in Argparser if wrong choice picked #99773
• gh-99749: Suggest closest choice in argparser, if wrong choice is picked #99831
• GH-99749: Add optional feature to suggest correct names (ArgumentParser) #124456
• GH-99749: Add What's New entry for #124456 #125671