Re: [PATCH v3 04/11] unpack-trees: introduce preserve_ignored to unpack_trees_options

On Sat, Oct 2, 2021 at 2:07 AM Ævar Arnfjörð Bjarmason [off-list ref] wrote:

On Fri, Oct 01 2021, Elijah Newren wrote:

...

quoted

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.