From: Max Horn <max@quendi.de>
Date: Thu, 31 Oct 2013 19:29:02 GMT
Subject: Re: [PATCH v5 09/10] fast-export: add support to delete refs
Message-ID: <6F276334-DFDB-40B8-8B24-38FFB6DBED9B@quendi.de>
In-Reply-To: <1383212197-14259-8-git-send-email-felipe.contreras@gmail.com>

Actually, I just noticed one thing that I *do* have a question about:

On 31.10.2013, at 10:36, Felipe Contreras <felipe.contreras@gmail.com> wrote:

> Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>
> ---
> builtin/fast-export.c  | 14 ++++++++++++++
> t/t9350-fast-export.sh | 11 +++++++++++
> 2 files changed, 25 insertions(+)
> 
> diff --git a/builtin/fast-export.c b/builtin/fast-export.c
> index b6f623e..8ed41b4 100644
> --- a/builtin/fast-export.c
> +++ b/builtin/fast-export.c
> @@ -673,6 +673,19 @@ static void import_marks(char *input_file)
> 	fclose(f);
> }
> 
> +static void handle_deletes(void)
> +{
> +	int i;
> +	for (i = 0; i < refspecs_nr; i++) {
> +		struct refspec *refspec = &refspecs[i];
> +		if (*refspec->src)
> +			continue;
> +
> +		printf("reset %s\nfrom %s\n\n",
> +				refspec->dst, sha1_to_hex(null_sha1));

If I understand it right, this issues a "reset" command in the fast-import stream, resetting a ref to an all-zero SHA1. I had a look at the git-fast-import documentation, but I found that it does not explicitly cover this case. In particular, the "reset" command does not specify that an all-zero SHA1 should be treated as "delete this ref". On the other hand, the docs for "reset" seem to indicate that one can omit the "from" part, although I couldn't tell for sure what that would mean, either.

I have not yet tried to dive into the code to figure out what actually happens, but I assume Felipe did that resp. tested it, and so supposedly doing this works, at least for git resp. existing transport helpers. But I wonder if other implementers of the fast-import format would handle it properly?

In any case, it seems to me that this is a gap in the documentation, isn't it? Or am I just being dense?