From: Junio C Hamano <gitster@pobox.com>
Date: Mon, 11 May 2015 22:39:46 GMT
Subject: Re: [PATCH v4 3/3] cat-file: add --follow-symlinks to --batch
Message-ID: <xmqqtwvi20y5.fsf@gitster.dls.corp.google.com>
In-Reply-To: <1431383471.15048.9.camel@ubuntu>

David Turner <dturner@twopensource.com> writes:

> I'll send something like this when I re-roll:
>
> Follow symlinks inside the repository when requesting objects with
> extended SHA-1 expressions of the form tree-ish:path-in-tree. Instead of
> providing output about the link itself, provide output about the
> linked-to object.  This option requires --batch or	--batch-check.  In
> the event of a symlink loop (or more than 40 symlinks in a symlink
> resolution chain), the file will be treated as missing.  If a symlink
> points outside the tree-ish (e.g. a link to /foo or a root-level link
> to ../foo), the portion of the link which is outside the tree will be
> printed. Follow-symlinks will be silently turned off if <object>
> specifies an object in the index rather than one in the object database.

Very understandable. I like it.

>
> I could also provide some examples, if you think this would be useful.

That may not be a bad idea.

>> > +symlink SP <size> LF <symlink> LF
>> > +------------
>> 
>> A symlink contain LF, obviously, and we should use some quoting
>> convention.  Perhaps quote_c_style() on a string that needs it is
>> sufficient---most sane people do not put LF or literally '\' 'n' or
>> '"' in their symbolic links, so the ugly output is not visible for
>> them, and it is far better to be able to say "If you have funny
>> characters in your symlinks, they will be quoted" than "If you have
>> funny characters in your symlinks, you are SOL".
>> 
> There is no need for quoting because <size> is sufficient to
> disambiguate the parsing (just as is the case for blobs, which might
> contain arbitrary characters).

OK.  That is a very sensible way to think about it.

I briefly wondered if trailing LF is a healthy thing, but blob
output also gives an extra LF after <contents> (i.e. the reader of
"<name> SP blob SP <size> LF <contents> LF" must skip (size + 1)
bytes to get to the next record), so it is consistent.

Thanks.