Re: [RFC PATCH 00/18] Multi-pack index (MIDX)

[Jeff King <peff@peff.net>]

On Mon, Jan 08, 2018 at 02:43:00PM +0100, Johannes Schindelin wrote:

> Take the interactive rebase for example. It generates todo lists with
> abbreviated commit names, for readability (and it is *really* important to
> keep this readable). As we expect new objects to be introduced by the
> interactive rebase, we convert that todo list to unabbreviated commit
> names before executing the interactive rebase.
> 
> Your idea (to not care about unambiguous abbreviations) would break that.

I think that could be easily worked around for rebase by asking git to
check ambiguity during the conversion. Speed is much less of a problem
there, because we're doing a relatively small number of abbreviations
(compared to "git log --oneline --raw", which is abbreviating almost
every object in the repository).

But I agree it's a potential problem for other scripts that we might not
have control over. I hadn't really intended this to be the default
behavior (my patch was just trying to show the direction). But it does
make for a pretty awful interface if callers have to opt into it
manually ("git log --oneline --no-really-go-fast").

I am a bit curious if there's a bounded probability that people would
find acceptable for Git to give an ambiguous abbreviation. We already
accept 1 in 2^160, of course. But would, e.g., one in a million be OK?

-Peff