Re: Concurrent fetch commands

[Taylor Blau <me@ttaylorr.com>]

On Wed, Jan 03, 2024 at 02:10:56PM -0800, Junio C Hamano wrote:
> Taylor Blau <me@ttaylorr.com> writes:
>
> > ... I suppose the answer is that they expect
> > concurrent fetches to be tolerated, but that the contents of FETCH_HEAD
> > (and of course the remote references) are consistent at the end of all
> > of the fetches.
>
> What does it mean to be "consistent" in this case, though?  For the
> controlled form of multiple fetches performed by "git fetch --all",
> the answer is probably "as if we fetched sequentially from these
> remotes, one by one, and concatenated what these individual fetch
> invocations left in FETCH_HEAD".  But for an uncontrolled background
> fetch IDE and others perform behind user's back, it is unclear what
> it means, or for that matter, it is dubious if there is a reasonable
> definition for the word.

Yeah, on thinking on it more I tend to agree here.

> Nobody brought up the latter so far on this discussion thread, but
> mucking with the remote-tracking branches behind user's back means
> completely breaking the end-user expectation that --force-with-lease
> would do something useful even when it is not given the commit the
> user expects to see at the remote.  Perhaps those third-party tools
> that want to run "git fetch" in the background can learn from how
> "prefetch" task works to avoid the breakage they are inflicting on
> their users?

Probably so.

Thanks,
Taylor