From: Junio C Hamano <gitster@pobox.com>
Date: Mon, 12 Nov 2018 15:03:12 GMT
Subject: Re: [PATCH 2/2] read-cache: use time_t instead of unsigned long
Message-ID: <xmqq7ehi1gpb.fsf@gitster-ct.c.googlers.com>
In-Reply-To: <nycvar.QRO.7.76.6.1811121554060.39@tvgsbejvaqbjf.bet>

Johannes Schindelin <Johannes.Schindelin@gmx.de> writes:

>> Given that the function returns the value obtained from
>> approxidate(), which is approxidate_careful() in disguise, time_t is
>> not as appropriate as timestamp_t, no?
>> 
>> IOW, what if time_t were narrower than timestamp_t?
>
> Riiiight. From the patch, I had assumed that the return type of
> `approxidate()` is `time_t`, but it is `timestamp_t`.

Yes, but if we dig a bit deeper, it turns out that the return value
of this function is used at only one place, to be compared with the
.st_mtime field.

So for this change to truly be consisent, not just the function
needs to return timestamp_t, but also its sole caller needs to check
if its return value exceeds the maximum span that is expressible
with the platform's time_t (and if so, treat the expiration to be
"infinity- never expire"), or something like that.