Bug: OptionHighlighter incorrectly captures all text between '<' and '>' as a metavar in help strings

[batidiane]

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Example Code

import typer

app = typer.Typer(rich_markup_mode="rich")

@app.command()
def explore(
    filter: str = typer.Option(
        None, 
        help="Filter data. Operators: <= (less/equal) and > (greater). E.g. cost>100"
    )
):
    pass

if __name__ == "__main__":
    app()

Description

When using rich_markup_mode="rich" in a Typer application, any help text that contains both a < and a > character causes all text between them to be highlighted as a metavar (typically yellow), even if they are just being used as mathematical operators or standard punctuation.

This happens because typer.rich_utils.OptionHighlighter includes the following regex in its highlights list:
r"(?P<metavar>\<[^\>]+\>)"

If a user writes a help string like: Operators include <= and >, the regex captures "= and " as a metavar, bleeding the yellow highlight across the text.

Operating System

Linux / macOS / Windows

Operating System Details

Irrelevant, applies to all OS environments.

Typer Version

0.12.0 (or whatever your current version is)

Python Version

3.10+

Steps to Reproduce

Run the following minimal reproducible example. Notice how the text between < and > is highlighted yellow in the terminal, breaking the intended formatting.

import typer

app = typer.Typer(rich_markup_mode="rich")

@app.command()
def explore(
    filter: str = typer.Option(
        None, 
        help="Filter data. Operators: <= (less/equal) and > (greater). E.g. cost>100"
    )
):
    pass

if __name__ == "__main__":
    app()

Proposed Solution

Currently, the only way to bypass this without altering the help text is to monkey-patch the OptionHighlighter before initializing the app:

import typer.rich_utils

# Monkey-patch to remove the aggressive metavar regex
typer.rich_utils.OptionHighlighter.highlights = [
    r for r in typer.rich_utils.OptionHighlighter.highlights
    if r"(?P<metavar>\<[^\>]+\>)" not in r
]

Potential fixes:

1. Scope the Regex: Restrict the metavar regex so it doesn't span across whitespace or punctuation, preventing it from swallowing entire sentences.
2. Opt-out Mechanism: Provide a configuration option in typer.Typer() or typer.Option() to disable the automatic OptionHighlighter on specific help strings where raw mathematical operators are required.
3. Rich Escaping Support: Ensure that standard Rich escaping (e.g., \< and \>) correctly bypasses the Typer-specific regex highlighter.

Operating System

macOS

Operating System Details

MacOS M4

Typer Version

0.24.0

Python Version

3.13.12

Additional Context

No response

[svlandeg]

Thanks for the PR! Do you want to submit a PR with the fix?