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| author | Russ Cox <rsc@golang.org> | 2022-04-25 14:06:10 -0400 |
|---|---|---|
| committer | Gopher Robot <gobot@golang.org> | 2022-04-26 02:28:58 +0000 |
| commit | 17d7983b29ba633708a9d7b18f90ab5bc029502d (patch) | |
| tree | 37a2799a2c7955a770fa5eb73435f031b6a863a3 | |
| parent | 09ada1af8f54584e46deb0d643713393a9d83b10 (diff) | |
| download | go-17d7983b29ba633708a9d7b18f90ab5bc029502d.tar.gz go-17d7983b29ba633708a9d7b18f90ab5bc029502d.zip | |
time: fix quickcheck test to avoid wraparounds
When we call time.Unix(s, ns), the internal representation is
s + 62135596800, where 62135596800 is the number of
seconds from Jan 1 1 to Jan 1 1970.
If quickcheck generates numbers too close to 2^63,
the addition can wraparound to make a very negative
internal 64-bit value. Wraparounds are not guarded
against, since they would not arise in any reasonable program,
so just avoid testing near them.
Fixes #52409.
Change-Id: Id466c8a34a49055ab26f2687a6b2b657cb64bed6
Reviewed-on: https://go-review.googlesource.com/c/go/+/402177
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Bryan Mills <bcmills@google.com>
Auto-Submit: Russ Cox <rsc@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
| -rw-r--r-- | src/time/time_test.go | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/src/time/time_test.go b/src/time/time_test.go index 1701401ab4..695d48b1b5 100644 --- a/src/time/time_test.go +++ b/src/time/time_test.go @@ -281,6 +281,8 @@ func TestTruncateRound(t *testing.T) { b1e9.SetInt64(1e9) testOne := func(ti, tns, di int64) bool { + t.Helper() + t0 := Unix(ti, int64(tns)).UTC() d := Duration(di) if d < 0 { @@ -367,6 +369,13 @@ func TestTruncateRound(t *testing.T) { for i := 0; i < int(b); i++ { d *= 5 } + + // Make room for unix ↔ internal conversion. + // We don't care about behavior too close to ± 2^63 Unix seconds. + // It is full of wraparounds but will never happen in a reasonable program. + // (Or maybe not? See go.dev/issue/20678. In any event, they're not handled today.) + ti >>= 1 + return testOne(ti, int64(tns), int64(d)) } quick.Check(f1, cfg) @@ -377,6 +386,7 @@ func TestTruncateRound(t *testing.T) { if d < 0 { d = -d } + ti >>= 1 // see comment in f1 return testOne(ti, int64(tns), int64(d)) } quick.Check(f2, cfg) @@ -399,6 +409,7 @@ func TestTruncateRound(t *testing.T) { // full generality f4 := func(ti int64, tns int32, di int64) bool { + ti >>= 1 // see comment in f1 return testOne(ti, int64(tns), di) } quick.Check(f4, cfg) |