From: Junio C Hamano <gitster@pobox.com>
To: "René Scharfe" <l.s.r@web.de>
Cc: Jeff King <peff@peff.net>, Git List <git@vger.kernel.org>
Subject: Re: [PATCH] describe: fix --no-exact-match
Date: Wed, 09 Aug 2023 12:07:07 -0700 [thread overview]
Message-ID: <xmqqzg30m3vo.fsf@gitster.g> (raw)
In-Reply-To: <22e5a87a-cd35-9793-5b6f-6eb368fdf40e@web.de> ("René Scharfe"'s message of "Wed, 9 Aug 2023 18:41:13 +0200")
René Scharfe <l.s.r@web.de> writes:
>> Here's what it looks like, for reference.
>>
>> diff --git a/builtin/describe.c b/builtin/describe.c
>> index b28a4a1f82..718b5c3073 100644
>> --- a/builtin/describe.c
>> +++ b/builtin/describe.c
>> @@ -561,9 +561,11 @@ static void describe(const char *arg, int last_one)
>> static int option_parse_exact_match(const struct option *opt, const char *arg,
>> int unset)
>> {
>> + int *val = opt->value;
>
> This line would assign opt->value_int instead...
>
>> +
>> BUG_ON_OPT_ARG(arg);
>>
>> - max_candidates = unset ? DEFAULT_CANDIDATES : 0;
>> + *val = unset ? DEFAULT_CANDIDATES : 0;
>> return 0;
>> }
>> ...
> Thoughts? Too much churn?
Sorry, but I am not sure what is being proposed. opt->value_int
would presumably be defined as a pointer to an int. The calling
side presumably defines the options[] array entry so that the
&max_candidates address is given to opt->value_int and not to
opt->value_someothertype, and if you try to pass a pointer of a
wrong type, it would be caught as a type mismatch by the compiler,
so the above covers both ends (i.e. the address &max_candidates is
passed in the correct member of the struct, and the callback takes
val out of the correct member of the struct), as long as the
callback uses the right type. If &max_candidates is int now, and
the above code is written to use opt->value_int, anybody who needs
to update max_candidates to ulong must make sure three things match,
i.e. the type of max_candidates variable itself, the member the
caller uses to pass &max_candidates in the struct (i.e. change to
use value_ulong and not value_int), and the type of the local
variable the callback function uses.
But I am failing to imagine how the calling side actually would look
like. Can we do something along the lines of
#define OPT_CALLBACK(s, l, v, a, h, cb)
.short_name = (s),
.long_name = (l),
.value_ ## typeof(v) = &v,
.help = (h),
.callback = (cb),
with a clever CPP trick? It sounds like either too much churn or
too much magic or both, at least to me.
Thanks.
next prev parent reply other threads:[~2023-08-09 19:07 UTC|newest]
Thread overview: 66+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-07-18 15:44 [PATCH] ls-tree: fix --no-full-name René Scharfe
2023-07-18 16:37 ` Junio C Hamano
2023-07-18 20:49 ` Junio C Hamano
2023-07-21 12:41 ` René Scharfe
2023-07-21 12:41 ` René Scharfe
2023-07-21 14:37 ` Junio C Hamano
2023-07-21 19:29 ` René Scharfe
2023-07-21 20:09 ` Junio C Hamano
2023-07-21 20:14 ` Junio C Hamano
2023-07-24 12:29 ` René Scharfe
2023-07-24 18:51 ` Junio C Hamano
2023-07-24 20:09 ` René Scharfe
2023-07-24 20:50 ` Junio C Hamano
2023-07-28 6:12 ` René Scharfe
2023-07-28 9:45 ` Phillip Wood
2023-07-29 20:40 ` René Scharfe
2023-07-31 15:31 ` Junio C Hamano
2023-08-04 16:40 ` Junio C Hamano
2023-08-04 19:48 ` Phillip Wood
2023-08-05 10:40 ` René Scharfe
2023-07-24 12:29 ` [PATCH v2 0/5] show negatability of options in short help René Scharfe
2023-07-24 12:34 ` [PATCH v2 1/5] subtree: disallow --no-{help,quiet,debug,branch,message} René Scharfe
2023-07-24 12:36 ` [PATCH v2 2/5] t1502, docs: disallow --no-help René Scharfe
2023-07-24 12:38 ` [PATCH v2 3/5] t1502: move optionspec help output to a file René Scharfe
2023-07-24 12:39 ` [PATCH v2 4/5] t1502: test option negation René Scharfe
2023-07-24 12:40 ` [PATCH v2 5/5] parse-options: show negatability of options in short help René Scharfe
2023-08-05 14:33 ` [PATCH v3 0/8] " René Scharfe
2023-08-05 14:37 ` [PATCH v3 1/8] subtree: disallow --no-{help,quiet,debug,branch,message} René Scharfe
2023-08-05 14:37 ` [PATCH v3 2/8] t1502, docs: disallow --no-help René Scharfe
2023-08-05 14:38 ` [PATCH v3 3/8] t1502: move optionspec help output to a file René Scharfe
2023-08-05 14:39 ` [PATCH v3 4/8] t1502: test option negation René Scharfe
2023-08-05 14:40 ` [PATCH v3 5/8] parse-options: show negatability of options in short help René Scharfe
2023-08-05 14:43 ` [PATCH v3 6/8] parse-options: factor out usage_indent() and usage_padding() René Scharfe
2023-08-05 14:44 ` [PATCH v3 7/8] parse-options: no --[no-]no- René Scharfe
2023-08-05 14:52 ` [PATCH v3 8/8] parse-options: simplify usage_padding() René Scharfe
2023-08-05 23:04 ` Junio C Hamano
2023-07-21 12:41 ` [PATCH] show-branch: fix --no-sparse René Scharfe
2023-07-21 14:42 ` Junio C Hamano
2023-07-21 16:30 ` René Scharfe
2023-07-21 12:41 ` [PATCH] show-branch: disallow --no-{date,topo}-order René Scharfe
2023-07-21 12:41 ` [PATCH] reset: disallow --no-{mixed,soft,hard,merge,keep} René Scharfe
2023-07-21 12:41 ` [PATCH] pack-objects: fix --no-quiet René Scharfe
2023-07-21 12:41 ` [PATCH] pack-objects: fix --no-keep-true-parents René Scharfe
2023-07-21 17:03 ` Junio C Hamano
2023-07-21 12:42 ` [PATCH] branch: disallow --no-{all,remotes} René Scharfe
2023-07-21 12:42 ` [PATCH] am: unify definition of --keep-cr and --no-keep-cr René Scharfe
2023-07-21 13:41 ` [PATCH] describe: fix --no-exact-match René Scharfe
2023-07-21 14:10 ` Junio C Hamano
2023-07-21 17:00 ` Junio C Hamano
2023-08-08 21:27 ` Jeff King
2023-08-08 21:28 ` Jeff King
2023-08-09 1:43 ` Junio C Hamano
2023-08-09 14:09 ` Jeff King
2023-08-09 16:41 ` René Scharfe
2023-08-09 19:07 ` Junio C Hamano [this message]
2023-08-10 0:26 ` Jeff King
2023-08-10 1:00 ` Junio C Hamano
2023-08-10 19:45 ` René Scharfe
2023-08-10 0:41 ` Jeff King
2023-08-10 19:10 ` René Scharfe
2023-08-11 15:11 ` Jeff King
2023-08-11 17:59 ` René Scharfe
2023-08-11 18:24 ` Jeff King
2023-08-12 5:11 ` René Scharfe
2023-08-11 15:13 ` Jeff King
2023-08-11 17:59 ` René Scharfe
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