From: Jeff King <peff@peff.net>
To: Junio C Hamano <gitster@pobox.com>
Cc: "René Scharfe" <l.s.r@web.de>,
"Ævar Arnfjörð Bjarmason" <avarab@gmail.com>,
git@vger.kernel.org
Subject: Re: [PATCH] push: comment on a funny unbalanced option help
Date: Thu, 2 Aug 2018 12:54:58 -0400 [thread overview]
Message-ID: <20180802165457.GC15984@sigill.intra.peff.net> (raw)
In-Reply-To: <xmqqftzw4weq.fsf@gitster-ct.c.googlers.com>
On Thu, Aug 02, 2018 at 08:31:57AM -0700, Junio C Hamano wrote:
> > diff --git a/parse-options.c b/parse-options.c
> > index 7db84227ab..fadfc6a833 100644
> > --- a/parse-options.c
> > +++ b/parse-options.c
> > @@ -660,7 +660,8 @@ int parse_options(int argc, const char **argv, const char *prefix,
> > static int usage_argh(const struct option *opts, FILE *outfile)
> > {
> > const char *s;
> > - int literal = (opts->flags & PARSE_OPT_LITERAL_ARGHELP) || !opts->argh;
> > + int literal = (opts->flags & PARSE_OPT_LITERAL_ARGHELP) || !opts->argh ||
> > + (opts->argh[0] == '<' && strchr(opts->argh, '>'));
>
> You are greedier than what I thought ;-) I would have limited this
> magic to the case where argh is surrounded by "<>", but you allow
> one closing ">" anywhere, which allows us to grab more complex cases.
>
> The lack of escape hatch to decline this auto-literal magic makes me
> somewhat nervous, but I do not offhand think of a reason why I do
> want an arg-help string that _begins_ with '<' to be enclosed by
> another set of "<>", so perhaps this is a good kind of magic.
I think that case is actually easy; once the caller provides a "<>",
they are in "literal" mode, so they are free to add extra brackets if
you want. I.e., any "<foo>bar" that you do want enclosed could be
spelled "<<foo>bar>". It's the opposite that becomes impossible: you do
not have an opening bracket and nor do you want one. But as long as we
retain LITERAL_ARGHELP for that case, we have an escape hatch.
I was going to suggest that this conversion has the downside of being
somewhat one-way. That is, it is easy for us to find affected sites now
since they contain the string LITERAL_ARGHELP. Whereas if we wanted to
back it out in the future, it is hard to know which sites are depending
on this new behavior.
But I am having trouble thinking of a reason we would want to back it
out. This makes most cases easier, and has a good escape hatch.
-Peff
PS I actually would have made the rule simply "does it begin with a
'<'", which seems simpler still. If people accidentally write "<foo",
forgetting to close their brackets, that is a bug under both the
old and new behavior (just with slightly different outcomes).
next prev parent reply other threads:[~2018-08-02 16:55 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-01 18:43 [PATCH] push: comment on a funny unbalanced option help Junio C Hamano
2018-08-01 20:46 ` Ævar Arnfjörð Bjarmason
2018-08-01 21:48 ` Junio C Hamano
2018-08-01 22:31 ` Ævar Arnfjörð Bjarmason
2018-08-02 12:16 ` René Scharfe
2018-08-02 14:21 ` Ævar Arnfjörð Bjarmason
2018-08-02 15:06 ` René Scharfe
2018-08-02 15:16 ` René Scharfe
2018-08-02 15:24 ` Junio C Hamano
2018-08-02 15:31 ` Junio C Hamano
2018-08-02 16:50 ` René Scharfe
2018-08-02 16:54 ` Jeff King [this message]
2018-08-02 18:46 ` René Scharfe
2018-08-02 19:17 ` [PATCH 1/6] add, update-index: fix --chmod argument help René Scharfe
2018-08-02 20:41 ` Ævar Arnfjörð Bjarmason
2018-08-02 20:59 ` Ramsay Jones
2018-08-02 21:17 ` Junio C Hamano
2018-08-02 21:04 ` Andrei Rybak
2018-08-02 21:16 ` Junio C Hamano
2018-08-02 19:17 ` [PATCH 2/6] difftool: remove angular brackets from " René Scharfe
2018-08-02 19:17 ` [PATCH 3/6] pack-objects: specify --index-version argument help explicitly René Scharfe
2018-08-02 19:17 ` [PATCH 4/6] send-pack: specify --force-with-lease " René Scharfe
2018-08-02 19:18 ` [PATCH 5/6] shortlog: correct option help for -w René Scharfe
2018-08-02 19:18 ` [PATCH 6/6] parse-options: automatically infer PARSE_OPT_LITERAL_ARGHELP René Scharfe
2018-08-02 20:05 ` Junio C Hamano
2018-08-03 8:13 ` Kerry, Richard
2018-08-03 10:39 ` Kerry, Richard
2018-08-02 20:01 ` [PATCH] push: comment on a funny unbalanced option help Junio C Hamano
2018-08-02 22:38 ` René Scharfe
2018-08-03 15:29 ` Junio C Hamano
2018-08-02 15:44 ` Re* " Junio C Hamano
2018-08-02 15:59 ` René Scharfe
2018-08-02 16:23 ` Junio C Hamano
2018-08-02 20:33 ` Ævar Arnfjörð Bjarmason
2018-08-02 20:36 ` Junio C Hamano
2018-08-03 4:42 ` René Scharfe
2018-08-03 15:30 ` Junio C Hamano
2018-08-01 22:57 ` Jonathan Nieder
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