Re: [PATCH v2 5/5] refs/debug: trim trailing LF from reflog message

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

Han-Wen Nienhuys <hanwen@google.com> writes:

> On Fri, Nov 26, 2021 at 9:16 AM Junio C Hamano <gitster@pobox.com> wrote:
>>
>> The API promises to have only LF, not CRLF, at the end, so
>> strbuf_trim_trailing_newline() is a bit overkill (and if payload
>> happened to end with CR, we would lose it).
>
> it would be best if there was a way to escape characters (ie. "\n" =>
> "\\n"). Do we have a function for that?

Mere escaping would not work in a backward compatible way, without a
trick.  It was envisioned that we probably could encode *and* signal
the fact that the message is encoded by appending a trailing SP at
the end of the message.  See the log message of 523fa69c (reflog:
cleanse messages in the refs.c layer, 2020-07-10) for details.

Having said that, that is about introducing a whole new reflog
message format (whose use is signalled by the trailing SP), and I
would prefer it to happen

 (1) after we integrate with reftable, and

 (2) implemented as an option in the normalize_reflog_message()
     function, so that no ref backends has to worry about it.

outside this topic.

> I beg to differ - despite this being fewer lines of code, I think
> pointer arithmetic is best avoided if possible.

I think repeated allocation and deallocation is best avoided, and
that is why I recommended it.  I do not see anything to fear in
poiter arithmetic, as long as it is done clearly (e.g. in a narrow
scope) and correctly.

If trace_printf() does not allow counted bytes "%.*s", the whole
discussion is moot; I didn't go back to check.