Re: [PATCH] fsck: do not crash on tag objects which do not contain an empty line

From: Junio C Hamano <gitster@pobox.com>
Date: Jun 8, 2007, 05:17 UTC
Message-ID: <7vmyzbm3cx.fsf@assigned-by-dhcp.cox.net>
In-Reply-To: <Pine.LNX.4.64.0706072338260.4046@racer.site>

Johannes Schindelin <Johannes.Schindelin@gmx.de> writes:

Show 9 quoted lines

> The first empty line in a tag object separates the header from the
> message. If the tag object has no empty line, do not crash, but
> complain loudly instead.
>
> Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
> ---
>
> 	I have no idea how this tag crept into one of my repos, but it is 
> 	no good to crash for git-fsck.

Absolutely. git-fsck is to find suspicious data and should not crash on them.

Thanks.

But it _does_ make me wonder how.  Recent git-tag does this

    ( printf 'object %s\ntype %s\ntag %s\ntagger %s\n\n' \
	"$object" "$type" "$name" "$tagger";
      cat "$GIT_DIR"/TAG_FINALMSG ) >"$GIT_DIR"/TAG_TMP

so even if TAG_FINALMSG (which is -m or edited message after filtering out the comments and git-stripspace) is empty, you would have the two LFs at the end of the header. Ancient "git-tag-script" did this, which is a moral equivalent with echo and has the same effect:

  ( echo -e "object $object\ntype $type\ntag $name\ntagger $tagger\n";
    cat .tagmsg ) > .tmp-t

Did this tag come from cvsimport (or svnimport) perhaps? We are in the process of updating its use of git-mktag to git-tag, but they use git-mktag and do not leave a blank line after the header (and they do not add any body).

I notice that gitk creates lightweight tag by hand (it directly goes to the filesystem) It should probably use git-tag as well.

I agree with you that if something does not have body, we should not require an empty trailing line after the header.