Task flag --shell <shell> not working without -- separator

[deevus]

Problem

The specific combination of --shell <shell> as a task flag doesn't work unless I use --. Other flag names work fine.

Repro

Task with --shell flag (doesn't work):

#!/usr/bin/env bash

#USAGE flag "--shell <shell>"

if [[ -n "$usage_shell" ]]; then
    echo "Selected shell: $usage_shell"
else
    echo "No shell selected (usage_shell is empty)"
fi

Running mise run test --shell bash outputs nothing.

Running mise run test -- --shell bash works and outputs "Selected shell: bash".

What works

If I rename the flag to something else (e.g., --sh <sh> or --exec <exec>), it works without the -- separator.

Environment

• mise version: 2025.8.8 macos-arm64 (2025-08-11)
• OS: macOS 15.5 on Apple M1 Pro

Notes

Seems like --shell might be conflicting with a mise internal flag? Not sure how to debug this further.

Could be something specific to my environment - would be good to know if others can reproduce this.

[docwhat]

This is a duplicate of #285