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

From: Junio C Hamano <[email-masked]>
Date: Tue, 26 Mar 2024 10:00:56 -0700

Dirk Gouders <[email-masked]> writes:

> 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.