Subject: Re: [PATCH] reflog: fix expire --single-worktree

From: Junio C Hamano <[email-masked]>
Date: Tue, 31 Oct 2023 08:11:05 +0900

René Scharfe <[email-masked]> writes:

> Am 29.10.23 um 23:31 schrieb Junio C Hamano:
>> René Scharfe <[email-masked]> writes:
>>
>>> ... and added a non-printable short flag for it, presumably by
>>> accident.
>>
>> Very well spotted.
>>
>> FWIW, with the following patch on top of this patch, all tests pass
>> (and without your fix, of course this notices the "\001" and breaks
>> numerous tests that use "git reflog").  So you seem to have found
>> the only one broken instance (among those that are tested, anyway).
>>
>>  parse-options.c | 3 ++-
>>  1 file changed, 2 insertions(+), 1 deletion(-)
>>
>> diff --git i/parse-options.c w/parse-options.c
>> index 093eaf2db8..be8bedba29 100644
>> --- i/parse-options.c
>> +++ w/parse-options.c
>> @@ -469,7 +469,8 @@ static void parse_options_check(const struct option *opts)
>>  			optbug(opts, "uses incompatible flags "
>>  			       "LASTARG_DEFAULT and OPTARG");
>>  		if (opts->short_name) {
>> -			if (0x7F <= opts->short_name)
>> +			if (opts->short_name &&
>> +			    (opts->short_name < 0x21 || 0x7F <= opts->short_name))
>
> Good idea.  This is equivalent to !isprint(opts->short_name), which I
> find to be more readable here.

Thanks---I didn't think of using !isprint() but you are right.  It
is much shorter.

I am not absolutely certain if it is easier to read, though.  I get
always confused when asking myself if SP, HT, and LF are printables.
(in other words, I cannot immediately answer "does 'printable' mean
'can be sent to a teletype and have it do what is expected to be
done?"---the question I should be asking myself is "is 'printable'
synonym to 'when printed, some ink is consumed'?").

> Seeing why "char short_opts[128];" a
> few lines up is big enough would become a bit harder, though.

Sorry, but I do not quite follow.  We used to allow anything below
0x7e; now we clip that range further to reject anything below 0x21.
If [128] was big enough, it still is big enough, no?

Because the type of .short_name member is "int", we could have had
negative number in there and access to short_opts[] on the next line
would have been out of bounds.  By clipping the lower bound, we get
rid of that risk, no?

>>  				optbug(opts, "invalid short name");
>>  			else if (short_opts[opts->short_name]++)
>>  				optbug(opts, "short name already used");