click-option-names.md

Understanding option names in Click

I hit a bug today where I had defined a Click option called open but in doing so I replaced the Python bulit-in open() function:

@click.command()
# ...
@click.option("-o", "--open", is_flag=True, help="Open Datasette in your web browser")
def my_command(open):
    # Now open() is no longer available

This inspired me to finally figure out how Click function argument names work. It's documented here: https://click.palletsprojects.com/en/7.x/options/#name-your-options

Short version: you can do this:

@click.command()
# ...
@click.option("-o", "--open", "open_browser", is_flag=True, help="Open Datasette in your web browser")
def my_command(open_browser):
    # Now open() can be used safely

Click will use the positional argument without any hyphen prefixes as the name of the argument. If none is provided it will use the first -- one. If that's not defined it will use the -o one - all with the hypens stripped.