Re: [PATCH v3] date: detect underflow/overflow when parsing dates with timezone offset

> Junio C Hamano <gitster@pobox.com> writes:
>
>> The CI build on Windows tells me that my worry was warranted.
>>
>>   https://github.com/git/git/actions/runs/9424299208/job/25964281907#step:4:643
>>
>> (GitHub seems to show the breakage details only to those who are
>> logged in, so you'd need to be logged in to visit that link)
>
> So here is what I accumulated in SQUASH??? patches on top of your
> topic while waiting for an updated version to unbreak the CI.
>
>  * The "end of git time" timestamp does not fit in time_t on 32-bit
>    systems, so I updated it to use timestamp_t at least for now.
>
>  * t0006 has two tests that use TIME_IS_64BIT,TIME_T_IS_64BIT
>    prerequisites; I introduced HAVE_64BIT_TIME to simplify them.
>
>  * nobody passes $4 to check_parse to tell it to expect a failure,
>    so I removed it.  It always expects success.
>
>  * check_parse now honors a global variable REQUIRE_64BIT_TIME that
>    is used as the prerequisite to run its test_expect_success; the
>    "near the end of git time" tests you added use the mechanism to
>    pass HAVE_64BIT_TIME prerequisite.
>
> The last one is a bit questionable, as it only "punts" on 32-bit
> systems, instead of making sure we get the expected error messages.
> I think it is OK to punt here and have a separate test that checks
> timestamp around year 2040 for that condition.
>
>  date.c          |  2 +-
>  t/t0006-date.sh | 20 ++++++++++++++------
>  2 files changed, 15 insertions(+), 7 deletions(-)
>
> diff --git a/date.c b/date.c
> index 95776c8a92..bee9fe8f10 100644
> --- a/date.c
> +++ b/date.c
> @@ -870,7 +870,7 @@ static int match_object_header_date(const char *date, timestamp_t *timestamp, in
>
>
>  /* timestamp of 2099-12-31T23:59:59Z, including 32 leap days */
> -static const time_t timestamp_max = ((2100L - 1970) * 365 + 32) * 24 * 60 * 60 - 1;
> +static const timestamp_t timestamp_max = (((timestamp_t)2100 - 1970) * 365 + 32) * 24 * 60 * 60 - 1;
>
>  /* Gr. strptime is crap for this; it doesn't have a way to require RFC2822
>     (i.e. English) day/month names, and it doesn't work correctly with %z. */
> diff --git a/t/t0006-date.sh b/t/t0006-date.sh
> index e8fdf361ad..fd373e1b39 100755
> --- a/t/t0006-date.sh
> +++ b/t/t0006-date.sh
> @@ -8,6 +8,11 @@ TEST_PASSES_SANITIZE_LEAK=true
>  # arbitrary reference time: 2009-08-30 19:20:00
>  GIT_TEST_DATE_NOW=1251660000; export GIT_TEST_DATE_NOW
>
> +if test_have_prereq TIME_IS_64BIT,TIME_T_IS_64BIT
> +then
> +	test_set_prereq HAVE_64BIT_TIME
> +fi
> +

>  check_relative() {
>  	t=$(($GIT_TEST_DATE_NOW - $1))
>  	echo "$t -> $2" >expect
> @@ -80,14 +85,15 @@ check_show raw "$TIME" '1466000000 -0200'
>
>  # arbitrary time absurdly far in the future
>  FUTURE="5758122296 -0400"
> -check_show iso       "$FUTURE" "2152-06-19 18:24:56 -0400" TIME_IS_64BIT,TIME_T_IS_64BIT
> -check_show iso-local "$FUTURE" "2152-06-19 22:24:56 +0000" TIME_IS_64BIT,TIME_T_IS_64BIT
> +check_show iso       "$FUTURE" "2152-06-19 18:24:56 -0400" HAVE_64BIT_TIME
> +check_show iso-local "$FUTURE" "2152-06-19 22:24:56 +0000" HAVE_64BIT_TIME
>
> -check_parse() {
> +REQUIRE_64BIT_TIME=
> +check_parse () {
>  	echo "$1 -> $2" >expect
> -	test_expect_${4:-success} "parse date ($1${3:+ TZ=$3})" "
> -	TZ=${3:-$TZ} test-tool date parse '$1' >actual &&
> -	test_cmp expect actual
> +	test_expect_success $REQUIRE_64BIT_TIME "parse date ($1${3:+ TZ=$3}) -> $2" "
> +		TZ=${3:-$TZ} test-tool date parse '$1' >actual &&
> +		test_cmp expect actual
>  	"
>  }
>
> @@ -133,6 +139,7 @@ check_parse '1969-12-31 23:59:59 Z' bad
>  check_parse '1969-12-31 23:59:59 +11' bad
>  check_parse '1969-12-31 23:59:59 -11' bad
>
> +REQUIRE_64BIT_TIME=HAVE_64BIT_TIME
>  check_parse '2099-12-31 23:59:59' '2099-12-31 23:59:59 +0000'
>  check_parse '2099-12-31 23:59:59 +00' '2099-12-31 23:59:59 +0000'
>  check_parse '2099-12-31 23:59:59 Z' '2099-12-31 23:59:59 +0000'
> @@ -147,6 +154,7 @@ check_parse '2100-00-00 00:00:00 +00' bad
>  check_parse '2100-00-00 00:00:00 Z' bad
>  check_parse '2100-00-00 00:00:00 -11' bad
>  check_parse '2100-00-00 00:00:00 +11' bad
> +REQUIRE_64BIT_TIME=
>
>  check_approxidate() {
>  	echo "$1 -> $2 +0000" >expect