Re: [PATCH] oidmap.h: strongly discourage using OIDMAP_INIT directly

[Johannes Schindelin <Johannes.Schindelin@gmx.de>]

Hi Junio,

On Fri, 22 Dec 2017, Junio C Hamano wrote:

> Brandon Williams <bmwill@google.com> writes:
> 
> >> -#define OIDMAP_INIT { { NULL } }
> >> +/*
> >> + * This macro initializes the data structure only incompletely, just enough
> >> + * to call oidmap_get() on an empty map. Use oidmap_init() instead.
> >> + */
> >> +#define OIDMAP_INIT_INCOMPLETELY { { NULL } }
> >
> > This is one way of approaching the problem.  Couldn't we also take the
> > approach like we have with oidset and ensure that when oidmap_get() or
> > _put() are called that if the oidmap isn't initialized, we simply do
> > that then?
> 
> Hmph.  Can you show how the alternative code would look like?

No, because I refuse to perform pointless work, in particular when I am
already pretty booked with work.

But you know how it would look like, right? The cmpfn() function would be
exported via oidmap.h, and a HASHMAP_INIT(cmpfn) would be introduced in
hashmap.h that would initialize everything zeroed out except for the
cmpfn.

But then you would review it and ask if there would be any use in adding
cmp_cb_data to the signature of the HASHMAP_INIT() macro, and I would have
to implement that, too.

And then nobody would use it, and the macro would very likely get
stale/incorrect. And then I would offer another patch reverting that
change (because there is no user) and replace it with this here patch.

As I said: pointless,
Dscho