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Re: [PATCH] t4212: handle systems with post-apocalyptic gmtime

From
Jeff King <peff@peff.net>
Date
Mar 26, 2014, 19:40 UTC
Message-ID
<20140326194043.GB14105@sigill.intra.peff.net>
In-Reply-To
<20140326193359.GA14105@sigill.intra.peff.net>
On Wed, Mar 26, 2014 at 03:33:59PM -0400, Jeff King wrote:
Show 8 quoted lines
> That being said, is the AIX value actually right? I did not look closely
> at first, but just assumed that it was vaguely right. But:
> 
>   999999999999999999 / (86400 * 365)
> 
> is something like 31 billion years in the future, not 160 million.
> A real date calculation will have a few tweaks (leap years, etc), but
> that is orders of magnitude off.
Assuming my math is right, then here is the most sensible patch, IMHO.
-- >8 --
Subject: t4212: loosen far-in-future test for AIX

One of the tests in t4212 checks our behavior when we feed gmtime a date so far in the future that it gives up and returns NULL. Some implementations, like AIX, may actually just provide us a bogus result instead.

It's not worth it for us to come up with heuristics that guess whether the return value is sensible or not. On good platforms where gmtime reports the problem to us with NULL, we will print the epoch value. On bad platforms, we will print garbage. But our test should be written for the lowest common denominator so that it passes everywhere.

Reported-by: Charles Bailey <cbailey32@bloomberg.net>
Signed-off-by: Jeff King <peff@peff.net>
---
 t/t4212-log-corrupt.sh | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)
diff --git a/t/t4212-log-corrupt.sh b/t/t4212-log-corrupt.sh
index 85c6df4..bb843ab 100755
--- a/t/t4212-log-corrupt.sh
+++ b/t/t4212-log-corrupt.sh
@@ -77,11 +77,14 @@ test_expect_success 'date parser recognizes time_t overflow' '
 '
 
 # date is within 2^63-1, but enough to choke glibc's gmtime
-test_expect_success 'absurdly far-in-future dates produce sentinel' '
+#
+# Ideally we would check the output to make sure we replaced it with
+# a useful sentinel value, but some platforms will actually hand us back
+# a nonsensical date. It is not worth our time to try to evaluate these
+# dates, so just make sure we didn't segfault or otherwise abort.
+test_expect_success 'absurdly far-in-future dates' '
 	commit=$(munge_author_date HEAD 999999999999999999) &&
-	echo "Thu Jan 1 00:00:00 1970 +0000" >expect &&
-	git log -1 --format=%ad $commit >actual &&
-	test_cmp expect actual
+	git log -1 --format=%ad $commit
 '
 
 test_done
-- 
1.9.1.656.ge8a0637
Previous: Jeff KingNext: Charles Bailey
Message 22 of 48 in “handle bogus commit dates”
  1. 0/5 handle bogus commit datesJeff King, Feb 24, 2014
  2. 1/5 t4212: test bogus timestamps with git-logJeff King, Feb 24, 2014
  3. 2/5 fsck: report integer overflow in author timestampsJeff King, Feb 24, 2014
  4. 3/5 date: check date overflow against time_tJeff King, Feb 24, 2014
  5. 4/5 log: handle integer overflow in timestampsJeff King, Feb 24, 2014
  6. Junio C HamanoFeb 24, 2014
  7. Jeff KingFeb 24, 2014
  8. Junio C HamanoFeb 24, 2014
  9. Jeff KingFeb 24, 2014
  10. Junio C HamanoFeb 24, 2014
  11. 5/5 log: do not segfault on gmtime errorsJeff King, Feb 24, 2014
  12. René ScharfeMar 22, 2014
  13. Jeff KingMar 24, 2014
  14. René ScharfeMar 24, 2014
  15. Jeff KingMar 24, 2014
  16. Charles BaileyMar 26, 2014
  17. Jeff KingMar 26, 2014
  18. t4212: handle systems with post-apocalyptic gmtimeJeff King, Mar 26, 2014
  19. Junio C HamanoMar 26, 2014
  20. Jeff KingMar 26, 2014
  21. Jeff KingMar 26, 2014
  22. Jeff KingMar 26, 2014
  23. Charles BaileyMar 26, 2014
  24. Jeff KingMar 26, 2014
  25. Charles BaileyMar 26, 2014
  26. Charles BaileyMar 26, 2014
  27. Jeff KingMar 26, 2014
  28. Charles BaileyMar 26, 2014
  29. Jeff KingMar 27, 2014
  30. Junio C HamanoMar 28, 2014
  31. Jeff KingMar 28, 2014
  32. Junio C HamanoMar 28, 2014
  33. Jeff KingMar 28, 2014
  34. Junio C HamanoMar 28, 2014
  35. Jeff KingApr 1, 2014
  36. 1/2 date: recognize bogus FreeBSD gmtime outputJeff King, Apr 1, 2014
  37. René ScharfeApr 1, 2014
  38. Junio C HamanoApr 1, 2014
  39. René ScharfeApr 1, 2014
  40. Jeff KingApr 1, 2014
  41. 2/2 t4212: loosen far-in-future test for AIXJeff King, Apr 1, 2014
  42. work around unreliable gmtime errors on AIXJeff King, Apr 1, 2014
  43. Junio C HamanoApr 1, 2014
  44. Jeff KingApr 1, 2014
  45. Junio C HamanoMar 26, 2014
  46. Jeff KingMar 26, 2014
  47. Junio C HamanoMar 26, 2014
  48. Jeff KingMar 26, 2014

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