Re: [PATCH 1/2] [GSOC] ref-filter: add obj-type check in grab contents

"ZheNing Hu via GitGitGadget" [off-list ref] writes:

 /* See grab_values */
-static void grab_sub_body_contents(struct atom_value *val, int deref, void *buf)
+static void grab_sub_body_contents(struct atom_value *val, int deref, void *buf,
+				   struct object *obj)

Neither this step or the next change needs anything but type member
of the 'obj' (and 'buf' is coming from oi.content of the result of
asking about that same 'obj').

I wonder if we should do one of the following:

 (1) stop passing "void *buf" and instead "struct expand_data
     *data", and use "data->content" to access "buf", which would
     allow you to access "data->type" to perform the added check.

 (2) instead of adding "struct obj *obj" to the parameters, just add
     "enum object_type type", as that is the only thing you need.

Obviously (2) is with lessor impact, but if it can be done safely
without breaking the code [*], (1) would probably be a much more
preferrable direction to go in the longer term.

    Side note [*].  A caller is allowed to choose to feed "buf" that
    is different from "oi.content" (perhaps buf may sometimes want
    to be a utf-8 recoded version of oi.content for certain types of
    objects) with the current system, but if we pass expand_data
    throughout the callchain, such a caller is broken, for example.