show_default and default_map don't play nice together

[ewjoachim]

#!/usr/bin/env python
import click

@click.command(context_settings={
    "show_default": True, "default_map": {"a": "b"}
})
@click.option("-a", default="c")
def func(a):
    print(a)

if __name__ == "__main__":
    func()

$ # This is expected
$ ./cli.py
b
$ # This is not (default should be b)
$ ./cli.py --help
Usage: cli.py [OPTIONS]

Options:
  -a TEXT  [default: c]
  --help   Show this message and exit.  [default: False]

Expected Behavior

I expect the default shown to be identical to the one being used.

Actual Behavior

The default shown was the value provided as default, without taking the default_map into account

Environment

• Python version: 3.7
• Click version: click==7.1.2

[ewjoachim]

I may be able to make a failing test or a PR if you point me to the right direction. Would calling lookup_default instead of .default in this line be enough ?

click/src/click/core.py

Line 1936 in bce4ea4

default_string = self.default

[davidism]

Seems plausible, happy to review a PR.

[ewjoachim]

Ok, I'll try to remember to communicate here whether it happens or not. If I have neither said nor committed anything by May 17th, assume I have forgotten about it and you're free to go :)

[ewjoachim]

Yay, done :)