Re: [PATCH v2] send-email: try to get fqdn by running hostname --fqdn on Linux and macOS

[Junio C Hamano <gitster@pobox.com>]

Aditya Garg <gargaditya08@live.com> writes:

> `hostname` is a popular command available on both Linux and macOS. As
> per the man-page[1], `hostname --fqdn` command returns the fully
> qualified domain name (FQDN) of the system. The current Net::Domain
> perl module being used in the script for the same has been quite
> unrealiable in many cases. Thankfully, we now have a better check for
> valid_fqdn, which does reject the invalid FQDNs given by this module
> properly, but at the same time, it will result in a fallback to
> 'localhost.localdomain' being used. `hostname --fqdn` has been quite
> reliable (probably even more reliable than the Net::Domain module) and
> before falling back to 'localhost.localdomain', we should try to use it.
> Interestingly, the `hostname` command is actually used by perl modules
> like Net::Domain[2] and Sys::Hostname[3] to get the hostname. So, lets
> give `hostname --fqdn` a chance as well!
>
> [1]: https://man7.org/linux/man-pages/man1/hostname.1.html
> [2]: https://github.com/Perl/perl5/blob/blead/cpan/libnet/lib/Net/Domain.pm#L88
> [3]: https://github.com/Perl/perl5/blob/blead/ext/Sys-Hostname/Hostname.pm#L93
>
> Signed-off-by: Aditya Garg <gargaditya08@live.com>
> ---
> v2: Avoid chomping $domain and assigning it to $maildomain if the command fails.
>
>  git-send-email.perl | 16 +++++++++++++++-
>  1 file changed, 15 insertions(+), 1 deletion(-)

Looks sensible. Will queue. Thanks.

> diff --git a/git-send-email.perl b/git-send-email.perl
> index 55b7e00d29..511f627ba6 100755
> --- a/git-send-email.perl
> +++ b/git-send-email.perl
> @@ -1393,8 +1393,22 @@ sub maildomain_mta {
>  	return $maildomain;
>  }
>  
> +sub maildomain_hostname_command {
> +	my $maildomain;
> +
> +	if ($^O eq 'linux' || $^O eq 'darwin') {
> +		my $domain = `(hostname --fqdn) 2>/dev/null`;
> +		if (!$?) {
> +			chomp($domain);
> +			$maildomain = $domain if valid_fqdn($domain);
> +		}
> +	}
> +	return $maildomain;
> +}
> +
>  sub maildomain {
> -	return maildomain_net() || maildomain_mta() || 'localhost.localdomain';
> +	return maildomain_net() || maildomain_mta() ||
> +		maildomain_hostname_command || 'localhost.localdomain';
>  }
>  
>  sub smtp_host_string {