Re: [PATCH] config: option transfer.ipversion to set transport protocol version for network fetches

[Alex Riesen <alexander.riesen@cetitec.com>]

Junio C Hamano, Fri, Sep 18, 2020 00:31:58 +0200:
> Alex Riesen <alexander.riesen@cetitec.com> writes:
> 
> > If the configuration variable is allowed to be set to that "lack of
> > preference" value, we kind of have a command line option for it:
> >
> >     git -c transfer.protocolFamily=any fetch ...
> 
> Yes.
> 
> But we typically do not count that as being able to override from
> the command line.  If "git fetch --ipv4" will defeat the configured
> "transfer.protoclFamily=ipv6", the users will expect there is some
> way to do the same and say they accept any protocol family to be
> used.

Makes sense. I even wondered myself why there is no way to override
an --ipv4/--ipv6 in command-line back to "any" with an option added
after it:

    $ cat my-fetch
    #!/bin/sh
    git fetch --ipv4 "$@"

    $ ./my-fetch --ipv46

But how about making the command-line and config option a list?
(renaming it to ipversion, as elsewhere in the discussion)

    git fetch --ipversions=ipv6,ipv8

Given multiple times, the last option wins, as usual:

    $ cat my-fetch
    #!/bin/sh
    git fetch --ipversions=ipv4 "$@"

    $ ./my-fetch --ipversions=all

BTW, transport.c already converts transport->family to bit-flags in
connect_setup.