On Tue, Aug 14, 2018 at 10:28:13AM -0700, Matthew DeVore wrote:
> The name "tree:0" allows later filtering based on depth, i.e. "tree:1"
> would filter out all but the root tree and blobs. In order to avoid
> confusion between 0 and capital O, the documentation was worded in a
> somewhat round-about way that also hints at this future improvement to
> the feature.
I'm OK with this as a name, since we're explicitly not supporting deeper
depths. But I'd note that "depth" is actually a tricky characteristic,
as it's not a property of the object itself, but rather who refers to
it. So:
- it's expensive to compute, because you have to actually walk all of
the possible commits and trees that could refer to it. This
prohibits a lot of other optimizations like reachability bitmaps
(though with some complexity you could cache the depths, too).
- you have to define it as something like "the minimum depth at which
this object is found", since there may be multiple depths
I think you can read that second definition between the lines of:
> +The form '--filter=tree:<depth>' omits all blobs and trees deeper than
> +<depth> from the root tree. Currently, only <depth>=0 is supported.
But I wonder if we should be more precise. It doesn't matter now, but it
may help set expectations if the feature does come later.
-Peff
