On Thu, Jul 26, 2018 at 11:04 AM Junio C Hamano <gitster@xxxxxxxxx> wrote:
> Ben Peart <peartben@xxxxxxxxx> writes:
> > I'm not thrilled with the long list either (the plethora of comments
> > probably makes it appear worse than it is) but I don't see how...
>
> If there were a simple and futureproof way to tell the option
> parsing loop to notice any feature other than "-b newbranch" was
> used, then such a whitelisting may be a viable way, but there is
> not, and the whitelist condition can become (over time---we are
> talking about futureproofing and not "a filter that happens to match
> today's feature set") just as complex as this blacklisting function
> is (e.g. feature A and feature B when used alone may be compatible
> with the optimization but not when used both), so if we were to use
> this optimization, I think this long list of special-case checks is
> the best we could do.
I'm wondering if a two-stage parse-options invocations could make this
potential maintenance problem more manageable by altogether
eliminating needs_working_tree_merge(). Something very roughly along
the lines of:
new_branch_and_passive_options = {
OPT_STRING('b', NULL, ...),
...options which can't impact "optimization" decision...
};
argc = parse_options(argc, argv, prefix,
new_branch_and_passive_options, NULL,
PARSE_OPT_KEEP_UNKNOWN | PARSE_OPT_KEEP_DASHDASH);
can_optimize_new_branch = 1;
for (i = 0; i < argc; i++)
if (argv[i][0] == '-') {
can_optimize_new_branch = 0;
break;
}
options = {
...all other options...
}
argc = parse_options(argc, argv, prefix, options,
checkout_usage, PARSE_OPT_KEEP_DASHDASH);
...as before...
The can_optimize_new_branch check could, of course, be fooled by a
non-option which starts with a "-", but that would err toward safety
of not optimizing, so shouldn't be a worry.
