# Re: \[PATCH v3 04/11\] unpack-trees: introduce preserve\_ignored to unpack\_trees\_options

- From: Elijah Newren \<hidden\>
- Date: 2021-10-04 13:54:43 
- List: git
- Page: https://ratatoskr.run/git/2021/10/7904441
- Thread: https://ratatoskr.run/git/2021/09/7902891/t.md

```text
On Sat, Oct 2, 2021 at 2:07 AM Ævar Arnfjörð Bjarmason [ref] wrote:
>
> On Fri, Oct 01 2021, Elijah Newren wrote:
>
...
> > So maybe I'll submit some patches on top that rip these direct members
> > out of of unpack_trees_options and push them inside some opaque
> > struct.
>
> Sure, that sounds good. I only had a mild objection to doing it in a way
> where you'll need that sort of code I removed in the linked commit in
> prep_exclude() because you were trying not to expose that at any cost,
> including via some *_INIT macro. I.e. if it's private we can just name
> it "priv_*" or have a :
>
>     struct dont_touch_this {
>         struct dir_struct dir;
>     };
>
> Which are both ways of /messaging/ that it's private, and since the
> target audience is just the rest of the git.git codebase I think that
> ultimately something that 1) sends the right message 2) makes accidents
> pretty much impossible suffices. I.e. you don't accidentally introduce a
> new API user accessing a field called "->priv_*" or
> "->private_*". Someone will review those patches...

An internal struct with all the members meant to be internal-only
provides nearly all the advantages that I was going for with the
opaque struct, while also being a smaller change than what I was
thinking of doing.  I like that idea; thanks for the suggestion.
```