Re: [PATCH v4 4/5] MyFirstObjectWalk: fix description for counting omitted objects

From: Junio C Hamano <gitster@pobox.com>
Date: Mar 26, 2024, 17:00 UTC
Message-ID: <xmqqo7b1apx3.fsf@gitster.g>
In-Reply-To: <20240326130902.7111-5-dirk@gouders.net>

Dirk Gouders <dirk@gouders.net> writes:

Show 18 quoted lines

> diff --git a/Documentation/MyFirstObjectWalk.txt b/Documentation/MyFirstObjectWalk.txt
> index a06c712e46..6901561263 100644
> --- a/Documentation/MyFirstObjectWalk.txt
> +++ b/Documentation/MyFirstObjectWalk.txt
> @@ -754,10 +754,12 @@ points to the same tree object as its grandparent.)
>  === Counting Omitted Objects
>  
>  We also have the capability to enumerate all objects which were omitted by a
> -filter, like with `git log --filter=<spec> --filter-print-omitted`. Asking
> -`traverse_commit_list_filtered()` to populate the `omitted` list means that our
> -object walk does not perform any better than an unfiltered object walk; all
> -reachable objects are walked in order to populate the list.
> +filter, like with `git log --filter=<spec> --filter-print-omitted`. To do this,
> +change `traverse_commit_list()` to `traverse_commit_list_filtered()`, which is
> +able to populate an `omitted` list.  This list of filtered objects may have
> +performance implications, however, because despite filtering objects, the possibly
> +much larger set of all reachable objects must be processed in order to
> +populate that list.

It may be just me not reading what is obvious to everybody else clearly, in which case I am happy to take the above text as-is, but the updated text that says a "list" may have "performance implications" reads a bit odd. It would be understandable if you said "asking for list of filtered objects may have", though.

Are you contrasting a call to traverse_commit_list() and traverse_commit_list_filtered() and discussing their relative performance?

Of are you contrasting a call to traverse_commit_list_filtered() with and without the omitted parameter, and saying that a call with omitted parameter asks the machinery to do more work so it has to cost more?

Other than that I had no trouble with this latest round.

Thanks.