Re: [PREVIEW v3 8/9] checkout-index: there are only two line terminators

From: Junio C Hamano <gitster@pobox.com>
Date: Jan 14, 2016, 17:13 UTC
Message-ID: <xmqq8u3skrsd.fsf@gitster.mtv.corp.google.com>
In-Reply-To: <20160114101830.GC30772@sigill.intra.peff.net>

Jeff King <peff@peff.net> writes:

> I see that we switch the line termination on the fly in option_parse_z.
> But I'm having trouble seeing how we could actually have mixed inputs.
> We don't actually look at the line-terminator until after all of the
> options are parsed.

I do not think we are aiming for mixed inputs. What I meant by "mixed" in my description was a possible future option to allow input and output using different line termination (e.g. via "-Z" you would control output line termination, while "-z" only affects the input line termination).

After this step, there is still one call that is more natural to have line_termination that is either '\0' or '\n' and that is on the output side, which calls write_name_quoted_relative() to report the names of the temporary files that received the file contents to the standard output.

Of course there is nothing wrong to do

        write_name_quoted_relative(name, prefix, stdout,
				   nul_term_lines ? '\0' : '\n');

though.

And I tend to think that it might even be a good idea to do so. If somebody in the future really wants to introduce '-Z', then they can add a separate "output_line_termination" variable back (and it would likely be set to '\0' or '\n' via "-z" when "-Z" is not given), but until then, I agree that a simple bool for "-z" would be better.

> I'm also not sure how "unset" would trigger here. If we have a long
> option, we can use "--no-foo". But there isn't a long option for "-z".
> Is there a way to negate short options?

I do not think there is. It merely future-proofs against those who try to add "--nul" as a longer synonym. They would complain after they add "--nul" in builtin_checkout_index_options[] as a synonym if they see "--no-nul" does not negate the effect of an earlier "-z".