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From: Junio C Hamano <gitster@pobox.com>
To: Jeff King <peff@peff.net>
Cc: Johannes Schindelin <johannes.schindelin@gmx.de>, git@vger.kernel.org
Subject: Re: [PATCH 0/6] Use time_t
Date: Wed, 01 Mar 2017 09:23:52 -0800	[thread overview]
Message-ID: <xmqq1sugj4gn.fsf@gitster.mtv.corp.google.com> (raw)
In-Reply-To: <20170228223325.vabdrwas2qn52gup@sigill.intra.peff.net> (Jeff King's message of "Tue, 28 Feb 2017 17:33:25 -0500")

Jeff King <peff@peff.net> writes:

> On Tue, Feb 28, 2017 at 02:27:22PM -0800, Junio C Hamano wrote:
>
>> Jeff King <peff@peff.net> writes:
>> 
>> > ... We can certainly stick with it for now (it's awkward if you
>> > really do have an entry on Jan 1 1970, but other than that it's an OK
>> > marker). I agree that the most negatively value is probably a saner
>> > choice, but we can switch to it after the dust settles.
>> 
>> I was trying to suggest that we should strive to switch to the most
>> negative or whatever the most implausible value in the new range
>> (and leave it as a possible bug to be fixed if we missed a place
>> that still used "0 is impossible") while doing the ulong to time_t
>> (or timestamp_t that is i64).  
>> 
>> "safer in the short term" wasn't meant to be "let's not spend time
>> to do quality work".  As long as we are switching, we should follow
>> it through.
>
> Sure, I'd be much happier to see it done now. I just didn't want to pile
> on the requirements to the point that step 1 doesn't get done.

Ah, that was what you meant.

I was assuming that we are switching to a longer _signed_ type.  It
felt silly to tell users "you can use timestamps before the epoch
now with this change, but you cannot express time exactly at the
epoch".

I am perfectly OK with switching to a longer _unsigned_ type with
the "0 is impossible" [*1*] intact, aka "safer in the short term",
if we want to it make our first step.  That may be a smaller step,
but still a step in the right direction.


[Footnote]

*1* It could be "-1 is impossible", I didn't actually check.
    Funnily enough, ISO C99 uses (time_t)(-1) to signal an error
    when returning value from mktime() and time().


  reply	other threads:[~2017-03-01 17:24 UTC|newest]

Thread overview: 113+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-02-27 21:30 [PATCH 0/6] Use time_t Johannes Schindelin
2017-02-27 21:30 ` [PATCH 1/6] t0006 & t5000: prepare for 64-bit time_t Johannes Schindelin
2017-02-27 22:55   ` Junio C Hamano
2017-02-27 21:30 ` [PATCH 2/6] Specify explicitly where we parse timestamps Johannes Schindelin
2017-02-27 22:37   ` Junio C Hamano
2017-02-27 22:51     ` Junio C Hamano
2017-02-28 10:49       ` Johannes Schindelin
2017-02-27 21:31 ` [PATCH 3/6] Introduce a new "printf format" for timestamps Johannes Schindelin
2017-03-01 18:20   ` Junio C Hamano
2017-03-01 19:53     ` Junio C Hamano
2017-02-27 21:31 ` [PATCH 4/6] Prepare for timestamps to use 64-bit signed types Johannes Schindelin
2017-02-27 21:31 ` [PATCH 5/6] ref-filter: avoid using `unsigned long` for catch-all data type Johannes Schindelin
2017-02-27 21:31 ` [PATCH 6/6] Use time_t where appropriate Johannes Schindelin
2017-02-27 22:48 ` [PATCH 0/6] Use time_t Junio C Hamano
2017-02-28 11:32   ` Johannes Schindelin
2017-02-28 14:28 ` Jeff King
2017-02-28 15:01   ` Johannes Schindelin
2017-02-28 16:38   ` René Scharfe
2017-02-28 18:55     ` Junio C Hamano
2017-02-28 20:04       ` Jeff King
2017-02-28 20:54       ` Johannes Schindelin
2017-02-28 21:31         ` Jeff King
2017-02-28 21:31         ` René Scharfe
2017-02-28 23:10           ` Johannes Schindelin
2017-03-01  0:59             ` René Scharfe
2017-02-28 17:26   ` Junio C Hamano
2017-02-28 20:01     ` Jeff King
2017-02-28 22:27       ` Junio C Hamano
2017-02-28 22:33         ` Jeff King
2017-03-01 17:23           ` Junio C Hamano [this message]
2017-04-02 19:06 ` [PATCH v2 0/8] Introduce timestamp_t for timestamps Johannes Schindelin
2017-04-02 19:06   ` [PATCH v2 1/8] ref-filter: avoid using `unsigned long` for catch-all data type Johannes Schindelin
2017-04-03  4:22     ` Torsten Bögershausen
2017-04-03 22:47       ` Johannes Schindelin
2017-04-02 19:06   ` [PATCH v2 2/8] t0006 & t5000: prepare for 64-bit timestamps Johannes Schindelin
2017-04-02 19:06   ` [PATCH v2 3/8] t0006 & t5000: skip "far in the future" test when time_t is too limited Johannes Schindelin
2017-04-02 19:06   ` [PATCH v2 4/8] Specify explicitly where we parse timestamps Johannes Schindelin
2017-04-03  4:26     ` Torsten Bögershausen
2017-04-03 22:50       ` Johannes Schindelin
2017-04-02 19:06   ` [PATCH v2 5/8] Introduce a new "printf format" for timestamps Johannes Schindelin
2017-04-02 19:06   ` [PATCH v2 6/8] Introduce a new data type " Johannes Schindelin
2017-04-02 19:07   ` [PATCH v2 7/8] Abort if the system time cannot handle one of our timestamps Johannes Schindelin
2017-04-02 19:07   ` [PATCH v2 8/8] Use uintmax_t for timestamps Johannes Schindelin
2017-04-20 20:52   ` [PATCH v3 0/8] Introduce timestamp_t " Johannes Schindelin
2017-04-20 20:52     ` [PATCH v3 1/8] ref-filter: avoid using `unsigned long` for catch-all data type Johannes Schindelin
2017-04-20 20:52     ` [PATCH v3 2/8] t0006 & t5000: prepare for 64-bit timestamps Johannes Schindelin
2017-04-20 20:58     ` [PATCH v3 3/8] t0006 & t5000: skip "far in the future" test when time_t is too limited Johannes Schindelin
2017-04-20 20:58     ` [PATCH v3 4/8] Specify explicitly where we parse timestamps Johannes Schindelin
2017-04-20 20:58     ` [PATCH v3 5/8] Introduce a new "printf format" for timestamps Johannes Schindelin
2017-04-20 20:58     ` [PATCH v3 6/8] Introduce a new data type " Johannes Schindelin
2017-04-20 20:58     ` [PATCH v3 7/8] Abort if the system time cannot handle one of our timestamps Johannes Schindelin
2017-04-20 20:59     ` [PATCH v3 8/8] Use uintmax_t for timestamps Johannes Schindelin
2017-04-21  6:05     ` [PATCH v3 0/8] Introduce timestamp_t " Junio C Hamano
2017-04-21 10:44       ` Johannes Schindelin
2017-04-21 10:45     ` [PATCH v4 0/9] " Johannes Schindelin
2017-04-21 10:45       ` [PATCH v4 1/9] ref-filter: avoid using `unsigned long` for catch-all data type Johannes Schindelin
2017-04-21 10:45       ` [PATCH v4 2/9] t0006 & t5000: prepare for 64-bit timestamps Johannes Schindelin
2017-04-21 10:45       ` [PATCH v4 3/9] t0006 & t5000: skip "far in the future" test when time_t is too limited Johannes Schindelin
2017-04-21 10:45       ` [PATCH v4 4/9] Specify explicitly where we parse timestamps Johannes Schindelin
2017-04-24  3:19         ` Junio C Hamano
2017-04-21 10:45       ` [PATCH v4 5/9] Introduce a new "printf format" for timestamps Johannes Schindelin
2017-04-21 10:45       ` [PATCH v4 6/9] Introduce a new data type " Johannes Schindelin
2017-04-21 10:45       ` [PATCH v4 7/9] Abort if the system time cannot handle one of our timestamps Johannes Schindelin
2017-04-24  3:16         ` Junio C Hamano
2017-04-24 13:57           ` Johannes Schindelin
2017-04-25  2:37             ` Junio C Hamano
2017-04-25  3:56             ` Junio C Hamano
2017-04-21 10:46       ` [PATCH v4 8/9] Use uintmax_t for timestamps Johannes Schindelin
2017-04-24  3:24         ` Junio C Hamano
2017-04-24 10:28           ` Johannes Schindelin
2017-04-25  3:59             ` Junio C Hamano
2017-04-25 20:10               ` Johannes Schindelin
2017-04-26  1:52                 ` Junio C Hamano
2017-04-26  3:45                   ` Junio C Hamano
2017-04-26  9:32                   ` Johannes Schindelin
2017-04-26 13:18                     ` Junio C Hamano
2017-04-21 10:46       ` [PATCH v4 9/9] show_date_ident(): defer date overflow check Johannes Schindelin
2017-04-24  3:29       ` [PATCH v4 0/9] Introduce timestamp_t for timestamps Junio C Hamano
2017-04-24  6:15         ` Jacob Keller
2017-04-24 14:02           ` Johannes Schindelin
2017-04-24 11:37         ` Jeff King
2017-04-25 20:13           ` Johannes Schindelin
2017-04-24 14:00         ` Johannes Schindelin
2017-04-24 13:57       ` [PATCH v5 0/8] " Johannes Schindelin
2017-04-24 13:57         ` [PATCH v5 1/8] ref-filter: avoid using `unsigned long` for catch-all data type Johannes Schindelin
2017-04-24 13:57         ` [PATCH v5 2/8] t0006 & t5000: prepare for 64-bit timestamps Johannes Schindelin
2017-04-24 13:58         ` [PATCH v5 3/8] t0006 & t5000: skip "far in the future" test when time_t is too limited Johannes Schindelin
2017-04-24 13:58         ` [PATCH v5 4/8] Specify explicitly where we parse timestamps Johannes Schindelin
2017-04-25  5:59           ` Junio C Hamano
2017-04-24 13:58         ` [PATCH v5 5/8] Introduce a new "printf format" for timestamps Johannes Schindelin
2017-04-24 13:58         ` [PATCH v5 6/8] Introduce a new data type " Johannes Schindelin
2017-04-26 16:43           ` Johannes Sixt
2017-04-26 19:18             ` Johannes Schindelin
2017-04-26 22:32           ` René Scharfe
2017-04-24 13:58         ` [PATCH v5 7/8] Abort if the system time cannot handle one of our timestamps Johannes Schindelin
2017-04-24 13:58         ` [PATCH v5 8/8] Use uintmax_t for timestamps Johannes Schindelin
2017-04-26 16:36           ` Johannes Sixt
2017-04-26 19:09             ` Johannes Schindelin
2017-04-25 21:54         ` [PATCH v5 0/8] Introduce timestamp_t " René Scharfe
2017-04-25 22:22           ` Johannes Schindelin
2017-04-26 22:09             ` René Scharfe
2017-04-26  1:56           ` Junio C Hamano
2017-04-26 19:20         ` [PATCH v6 " Johannes Schindelin
2017-04-26 19:26           ` [PATCH v6 1/8] ref-filter: avoid using `unsigned long` for catch-all data type Johannes Schindelin
2017-04-26 19:26           ` [PATCH v6 2/8] t0006 & t5000: prepare for 64-bit timestamps Johannes Schindelin
2017-04-26 19:26           ` [PATCH v6 3/8] t0006 & t5000: skip "far in the future" test when time_t is too limited Johannes Schindelin
2017-04-26 19:26           ` [PATCH v6 4/8] Specify explicitly where we parse timestamps Johannes Schindelin
2017-04-26 19:29           ` [PATCH v6 5/8] Introduce a new "printf format" for timestamps Johannes Schindelin
2017-04-26 19:29           ` [PATCH v6 6/8] Introduce a new data type " Johannes Schindelin
2017-05-20  5:47             ` [PATCH] name-rev: change a "long" variable to timestamp_t Junio C Hamano
2017-05-22 13:39               ` Johannes Schindelin
2017-04-26 19:29           ` [PATCH v6 7/8] Abort if the system time cannot handle one of our timestamps Johannes Schindelin
2017-04-26 19:29           ` [PATCH v6 8/8] Use uintmax_t for timestamps Johannes Schindelin

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