Re: [PATCH 2/2] rev-list: add --disk-usage option for calculating disk usage

From: Jeff King <peff@peff.net>
Date: Jan 27, 2021, 23:34 UTC
Message-ID: <YBH4b04kZL8V6GFe@coredump.intra.peff.net>
In-Reply-To: <YBHv0ZHZD4VMHLYR@nand.local>

On Wed, Jan 27, 2021 at 05:57:21PM -0500, Taylor Blau wrote:

Show 10 quoted lines

> > You can find that out by generating a list of objects, getting their
> > sizes from cat-file, and then summing them, like:
> >
> >     git rev-list --objects main..branch
> >     cut -d' ' -f1 |
> 
> I suspect that this is from the original commit message that you wrote a
> half-decade ago. Not that it really means much, but you could shave one
> process off of this example by passing '--no-object-names' to 'git
> rev-list'.

That, plus my muscle memory to do the cut. We should probably model the better form here, and use it in the test, though (not worth a re-roll on its own, but it looks like there are a few other minor bits).

Show 19 quoted lines

> >   - not counting up all reachable objects (i.e., requiring --objects for
> >     this output, and omitting it just counts up commits). This could be
> >     handled in the bitmap case with some extra code (OR-ing with the
> >     type bitmaps).
> >
> >     But after 5 years of this patch, I've never wanted that once. The
> >     disk usage of just some of the objects isn't really that useful (and
> >     of course you can still get it by piping to cat-file).
> 
> Yeah. I think it's trivial to support it, but I'm in favor of a simpler
> interface.
> 
> That said, I worry about painting ourselves into a corner if the default
> implies --objects. If we wanted to change that, I'm pretty sure you'd
> have to write a rule that says "imply objects, unless --tags, --blobs or
> etc. are specified, and then only do that".
> 
> Maybe we'll never have to address that, but it's worth thinking about
> before committing to implying '--objects'.

Yeah, the one thing that gives me pause is that it would be hard to undo later. I didn't write the code to handle it in the bitmap case, but I don't think it would be _too_ bad. It is slightly annoying for the all-objects case, because the existing code isn't set up well to iterate either a specific type, or all types.

> I have no comments on the patch itself, which looks fine to me (and I
> have seen over and over again as it seems to regularly cause conflicts
> when merging new releases into GitHub's fork :-)).

You are exposing my ulterior motive. :)

-Peff