Re: "disabling bitmap writing, as some objects are not being packed"?

[Jeff King <peff@peff.net>]

On Fri, Dec 16, 2016 at 01:28:00PM -0800, Junio C Hamano wrote:

> > 2. I don't understand what would cause that message.  That is, what bad
> > thing am I doing that I should stop doing?  I've briefly skimmed the
> > code and commit message, but the answer isn't leaping out at me.
> 
> Enabling bitmap generation for incremental packing that does not
> cram everything into a single pack is triggering it, I would
> presume.  Perhaps we should ignore -b option in most of the cases
> and enable it only for "repack -a -d -f" codepath?  Or detect that
> we are being run from "gc --auto" and automatically disable -b?  I
> have a feeling that an approach along that line is closer to the
> real solution than tweaking report_last_gc_error() and trying to
> deduce if we are making any progress.

Ah, indeed. I was thinking in my other response that "git gc" would
always kick off an all-into-one repack. But "gc --auto" will not in
certain cases. And yes, in those cases you definitely would want
--no-write-bitmap-index. I think it would be reasonable for "git repack"
to disable bitmap-writing automatically when not doing an all-into-one
repack.

-Peff