RE: [PATCH v3 0/2] Add hostname condition to includeIf

[<rsbecker@nexbridge.com>]

On Tuesday, March 19, 2024 5:37 PM, Dirk Gouders wrote:
>Junio C Hamano <gitster@pobox.com> writes:
>
>> Eric Sunshine <sunshine@sunshineco.com> writes:
>>
>>> Peff felt that adding `git config --show-hostname-for-includes` was
>>> probably overkill, but I'd argue that it is necessary to enable users
>>> to deterministically figure out the value to use in their
>>> configuration rather than having to grope around in the dark via
>>> guesswork and trial-and-error to figure out exactly what works.
>>>
>>> And the option name doesn't necessarily have to be so verbose; a
>>> shorter name, such as `git config --show-hostname` may be good enough.
>>> Implementing this option would also obviate the need to implement
>>> `test-tool xgethostname` (though, I agree with Junio that `test-tool
>>> gethostname` would have been a better, less implementation-revealing
>>> name).
>>
>> Yeah, I like that show-hostname thing (which I do not know if "config"
>> is a good home for, though).
>
>A thought when I was reading this: wouldn't it be enough to document that
`uname -n` can be used to get the hostname that should
>be used?
>
>As far as I know this should be POSIX-compliant and uses gethostname(2).

As previously pointed out, uname -n and gethostname(2) are not equivalent.
uname -n does not (depending on implementation) go to DNS while
gethostname(2) goes to DNS first (although apparently glibc may not). This
is particularly important in a multi-home situation where more than one IP
adapter has a different IP address on the same host, and where DNS does not
consider the different addresses to be equivalent (which otherwise could
cause problems for reverse lookups).
--Randall