Re: [RFC 4/4] Add cat-blob report pipe from fast-import to remote-helper.

From: Jeff King <peff@peff.net>
Date: Jun 5, 2012, 09:07 UTC
Message-ID: <20120605090702.GA27376@sigill.intra.peff.net>
In-Reply-To: <4FCDC894.7000905@viscovery.net>

On Tue, Jun 05, 2012 at 10:51:32AM +0200, Johannes Sixt wrote:

Show 5 quoted lines

> > Note that preexec_cb does not work at all on Windows, as it assumes a
> [... a very nice explanation of the pipe issues ...]
> 
> IOW: Everything that uses --cat-blob-fd or a similar facility cannot work
> on Windows without considerable additional effort.

Thanks, Johannes, that makes sense to me.

Florian, does that mean that making the svn helper start to use --cat-blob-fd at all is a potential regression for Windows? The fast-import documentation says that the cat-blob output will go to stdout now. Does it even work at all now? I don't really know or understand all of the reasons for cat-blob-fd to exist in the first place.

I expect one answer might be "well, the svn remote helper does not work at all on Windows already, so there's no regression". But this affects _all_ fast-import calls that git's transport-helper makes. Are there other ones that use import, and would they be affected by this?

For that matter, isn't this a backwards-incompatible change for other third-party helpers? Won't they need to respect the new GIT_REPORT_FILENO environment variable? Do we need the helper to specify "yes, I am ready to handle cat-blob-fd" in its capabilities list?

-Peff