Git's source code refers to timestamps as unsigned longs.  On 32-bit
platforms, as well as on Windows, unsigned long is not large enough
to capture dates that are "absurdly far in the future".

While we can fix this issue properly by replacing unsigned long with
a larger type, we want to be a bit more conservative and just skip
those tests on the maint track.

The test helper reads the timestamp given from the command line into
"unsigned long" using strtol(), which gives us LONG_MAX upon
overflow, so feeding 9999999999 and seeing the resulting "timestamp"
shown in year 2038 is a sufficient check for that condition.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Helped-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

When we want to know the local timezone offset at a given
timestamp, we compute it by asking for localtime() at the
given time, and comparing the offset to GMT at that time.
However, there's some juggling between time_t and "struct
tm" which happens, which involves calling our own
tm_to_time_t().

If that function returns an error (e.g., because it only
handles dates up to the year 2099), it returns "-1", which
we treat as a time_t, and is clearly bogus, leading to
bizarre timestamps (that seem to always adjust the time back
to (time_t)(uint32_t)-1, in the year 2106).

It's not a good idea for local_tzoffset() to simply die
here; it would make it hard to run "git log" on a repository
with funny timestamps. Instead, let's just treat such cases
as "zero offset".

Reported-by: Norbert Kiesel <nkiesel@gmail.com>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

We ended up testing some of these date formats throughout
the rest of the suite (e.g., via for-each-ref's
"$(authordate:...)" format), but we never did so
systematically. t0006 is the right place for unit-testing of
our date-handling code.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

The "show" tests are really only checking relative formats;
we should make that more clear.

This also frees up the "show" name to later check other
formats. We could later fold "relative" into a more generic
"show" command, but it's not worth it.  Relative times are a
special case already because we have to munge the concept of
"now" in our tests.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

* jk/war-on-sprintf:
  archive-tar: convert snprintf to xsnprintf

Commit f2f0267 (archive-tar: use xsnprintf for trivial
formatting, 2015-09-24) converted cases of "sprintf" to
"xsnprintf", but accidentally left one as just "snprintf".
This meant that we could silently truncate the resulting
buffer instead of flagging an error.

In practice, this is impossible to achieve, as we are
formatting a ustar checksum, which can be at most 7
characters. But the point of xsnprintf is to document and
check for "should be impossible" conditions; this site was
just accidentally mis-converted during f2f0267.

Noticed-by: Paul Green <Paul.Green@stratus.com>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

* mm/doc-hooks-linkgit-fix:
  Documentation: fix broken linkgit to git-config

Signed-off-by: Matthieu Moy <Matthieu.Moy@imag.fr>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

* es/st-add4-gcc-4.2-workaround:
  git-compat-util: st_add4: work around gcc 4.2.x compiler crash

Although changes by 5b442c4 (tree-diff: catch integer overflow in
combine_diff_path allocation, 2016-02-19) are perfectly valid, they
unfortunately trigger an internal compiler error in gcc 4.2.x:

    combine-diff.c: In function 'diff_tree_combined':
    combine-diff.c:1391: internal compiler error: Segmentation fault: 11

Experimentation reveals that changing st_add4()'s argument evaluation
order is sufficient to sidestep this problem.

Although st_add3() does not trigger the compiler bug, for style
consistency, change its argument evaluation order to match.

Signed-off-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>