GeezerVison

Since #355, _mk_option_line expands %(default)s in the help text first and only then checks whether the text already mentions a default. Once the placeholder has become its value, the word "default" is usually gone, so the extension appends its own (default: ...) and the value shows up twice.

parser.add_argument("--format", default="text", help="output format [%(default)s]")
parser.add_argument("--jobs", type=int, default=4, help="run %(default)s jobs in parallel")

1.24.2, text builder:

* **"--format"** "FORMAT" - output format [text] (default: "text")
* **"--jobs"** "JOBS" - run 4 jobs in parallel (default: "4")

--help prints output format [text] and run 4 jobs in parallel, which is what the page should say too. #355's own message says pages that already spell out the default should lose the duplicate; the existing test only passed because its help happens to contain the literal word (count (default: %(default)s)).

argparse's ArgumentDefaultsHelpFormatter makes this decision on the raw help ('%(default)' not in action.help), so the condition now checks the raw help as well as the expanded text.

roots/test-help-format-specifiers/parser.py gains --fmt with help="format [%(default)s]" and the expected output in test_help_format_specifiers shows it without a suffix. Changelog fragment included.

Verified in a python:3.12 container with the test dependency group:

• this branch: 75 passed
• the updated test against main's src: test_help_format_specifiers fails with the duplicated (default: "text")