Re: [RFC PATCH 2/7] path-walk: support `tree:0` filter

[Derrick Stolee <stolee@gmail.com>]

On 5/3/2026 8:11 PM, Taylor Blau wrote:
> The `tree:0` object filter omits all trees and blobs from the result,
> keeping only commits and tags. Consequently, this filter type should
> has a fairly straightforward integration with path-walk, as the decision
> to include an object depends only on its type and does not depend on any
> path-sensitive state.

I agree that the implementation here is straight-forward. It's something
where I could easily see wanting to disable the path-walk API because it
is no longer contributing much value, but perhaps the caller wants a
consistent callback that provides all commits and tags in different
chunks.
> Non-zero tree-depth filters are not supported. Those depend on the depth
> at which a tree is visited, which is a path-walk concept the filter
> machinery doesn't currently share with the path-walk API. Reject them in
> `prepare_filters()` with a helpful error and let pack-objects fall back
> to the regular traversal, the same way it already does for unsupported
> filters.

I think that this could be remedied with some tweaks to the internal
methods and data within the path-walk API to track a depth. This could
be handled later, if there was enough demand for nonzero tree-depth.

The diff itself looks good.

Thanks,
-Stolee