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

[ZheNing Hu <adlternative@gmail.com>]

Taylor Blau <me@ttaylorr.com> 于2023年4月9日周日 10:26写道：
>
> On Sat, Apr 08, 2023 at 10:19:52PM -0400, Taylor Blau wrote:
> > 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'
>

This looks like a mistake. Try passing a tree oid to git rev-list:

git rev-list --objects --stdin --no-walk --filter='object:type=blob'
<<< HEAD^{tree}
27f9fa75c6d8cdae7834f38006b631522c6a5ac3
4860bebd32f8d3f34c2382f097ac50c0b972d3a0 .cirrus.yml
c592dda681fecfaa6bf64fb3f539eafaf4123ed8 .clang-format
f9d819623d832113014dd5d5366e8ee44ac9666a .editorconfig
b0044cf272fec9b987e99c600d6a95bc357261c3 .gitattributes
...

> 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