Re: [PATCH] attr: do not mark queried macros as unset

[Stefan Beller <sbeller@google.com>]

> I dunno. This is why I submitted the initial patch as the simplest fix. ;)
>

The first patch is
Reviewed-by: Stefan Beller <sbeller@google.com>

Diffing across both patches, this seems to be the relevant part:

---8<---
@@ -1111,14 +1116,13 @@ static void collect_some_attrs(const struct
index_state *istate,

        prepare_attr_stack(istate, path, dirlen, &check->stack);
        all_attrs_init(&g_attr_hashmap, check);
-       determine_macros(check->all_attrs, check->stack);

        if (check->nr) {
                rem = 0;
                for (i = 0; i < check->nr; i++) {
                        int n = check->items[i].attr->attr_nr;
                        struct all_attrs_item *item = &check->all_attrs[n];
-                       if (item->macro) {
+                       if (!item->attr->in_stack) {
                                item->value = ATTR__UNSET;
                                rem++;
                        }
@@ -1127,6 +1131,8 @@ static void collect_some_attrs(const struct
index_state *istate,
                        return;
        }

+       determine_macros(check->all_attrs, check->stack);
+
        rem = check->all_attrs_nr;
        fill(path, pathlen, basename_offset, check->stack,
check->all_attrs, rem);
 }
---8<---

which I think is correct.

Maybe we could refactor the big condition (if (check->nr)) to be
its own function and have

    if (!check_overlaps_all_attrs(check))
        return;

instead. The function would allow for a natural place to put a comment
convincing us why the optimisation works as expected. :-)

And after rereading that code, the optimisation checks
if any of the requested attributes in 'check' are touched in
all_attrs, which sounds like a natural optimisation when we assume
that filling in the actual values take a lot of time as the stack
of attribute files might be large.

I think this patch is correct, too.

Stefan