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

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

quoted

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