Subject: Re: Lift --stdout restriction for using reachability bitmap in pack-objects?

From: Jeff King <[email-masked]>
Date: Tue, 17 Feb 2015 05:13:44 -0500

On Tue, Feb 17, 2015 at 05:07:36PM +0700, Duy Nguyen wrote:

> Commit 6b8fda2 (pack-objects: use bitmaps when packing objects -
> 2013-12-21) turns off reachability bitmap optimization if --stdout is
> not specified. I wonder if we could lift this restriction?

I'm not sure what else would break if we did. For instance, would
bitmaps kick in when doing the "Counting objects" phase of "git repack
-ad". And if so, what would the resulting pack look like?

So I'm not opposed to it in principle, but I suspect there's some
cleanup work to be done. But...

> My use case is debugging pack-objects in gdb (repeatedly) where this
> optimization could really save time. But specifying --stdout would
> clutter gdb interface.. I don't know this code well enough to judge,
> but I think the worst thing is we don't write .idx file out (maybe
> because it would involve a lot more work).

If the only reason is for gdb, then perhaps:

  set args pack-objects --stdout </dev/null >/dev/null

in gdb would help?

-Peff