Re: [Question] Can git cat-file have a type filtering option?

From: Taylor Blau <me@ttaylorr.com>
Date: Apr 9, 2023, 02:26 UTC
Message-ID: <ZDIiO1HMjej+rnMk@nand.local>
In-Reply-To: <ZDIgyKDQ2rJT2YEI@nand.local>

On Sat, Apr 08, 2023 at 10:19:52PM -0400, Taylor Blau wrote:

Show 12 quoted lines

> On Sat, Apr 08, 2023 at 09:28:28PM -0400, Taylor Blau wrote:
> > > I don't think so. While `git rev-list` traverses objects and performs
> > > filtering within a revision, `git cat-file --batch-all-objects` traverses
> > > all loose and packed objects. It might be difficult to perfectly
> > > extract the filtering from `git rev-list` and apply it to `git cat-file`.
> >
> > `rev-list`'s `--all` option does exactly the former: it looks at all
> > loose and packed objects instead of doing a traditional object walk.
>
> Sorry, this isn't right: --all pretends as if you passed all references
> to it over argv, not to just look at the individual loose and packed
> objects.

The right thing to do here if you wanted to get a listing of all blobs in your repository regardless of their reachability or whether they are loose or packed is:

    git cat-file --batch-check='%(objectname)' --batch-all-objects |
    git rev-list --objects --stdin --no-walk --filter='object:type=blob'

Or, if your filter is as straightforward as "is this object a blob or not", you could write something like:

    git cat-file --batch-check --batch-all-objects | awk '
      if ($2 == "blob") { print $0 }'

Or you could tighten up the AWK expression by doing something like:

    git cat-file --batch-check='%(objecttype) %(objectname)' \
      --batch-all-objects | awk '/^blob / { print $2 }'

Sorry for the brain fart.

Thanks, Taylor