From 5629b666e53e1289e977f3a55bb7397cd542f7a9 Mon Sep 17 00:00:00 2001
From: Tim Hockin <thockin@google.com>
Date: Mon, 2 Aug 2021 13:54:19 -0700
Subject: [PATCH] Automated cherry pick of #104014: Update
 golang.org/x/time/rate (#104018)

* Add failing test case

* Update golang.org/x/time/rate

* Call update-internal-modules from update-vendor

Kubernetes-commit: 64ab974abe00396a527905d247fb09808b25b8c3
---
 go.mod                            |  2 +-
 go.sum                            |  4 ++--
 util/flowcontrol/throttle_test.go | 34 +++++++++++++++++++++++++++++++
 3 files changed, 37 insertions(+), 3 deletions(-)

diff --git a/go.mod b/go.mod
index 15e69ed1f6..cb215ea8e3 100644
--- a/go.mod
+++ b/go.mod
@@ -28,7 +28,7 @@ require (
 	golang.org/x/net v0.0.0-20210520170846-37e1c6afe023
 	golang.org/x/oauth2 v0.0.0-20200107190931-bf48bf16ab8d
 	golang.org/x/term v0.0.0-20210220032956-6a3ed077a48d
-	golang.org/x/time v0.0.0-20210220033141-f8bda1e9f3ba
+	golang.org/x/time v0.0.0-20210723032227-1f47c861a9ac
 	google.golang.org/protobuf v1.26.0
 	k8s.io/api v0.0.0-20210716001550-68328c152cca
 	k8s.io/apimachinery v0.0.0-20210712060818-a644435e2c13
diff --git a/go.sum b/go.sum
index b3d07ef9a1..2556b276bc 100644
--- a/go.sum
+++ b/go.sum
@@ -322,8 +322,8 @@ golang.org/x/text v0.3.6/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
 golang.org/x/time v0.0.0-20181108054448-85acf8d2951c/go.mod h1:tRJNPiyCQ0inRvYxbN9jk5I+vvW/OXSQhTDSoE431IQ=
 golang.org/x/time v0.0.0-20190308202827-9d24e82272b4/go.mod h1:tRJNPiyCQ0inRvYxbN9jk5I+vvW/OXSQhTDSoE431IQ=
 golang.org/x/time v0.0.0-20191024005414-555d28b269f0/go.mod h1:tRJNPiyCQ0inRvYxbN9jk5I+vvW/OXSQhTDSoE431IQ=
-golang.org/x/time v0.0.0-20210220033141-f8bda1e9f3ba h1:O8mE0/t419eoIwhTFpKVkHiTs/Igowgfkj25AcZrtiE=
-golang.org/x/time v0.0.0-20210220033141-f8bda1e9f3ba/go.mod h1:tRJNPiyCQ0inRvYxbN9jk5I+vvW/OXSQhTDSoE431IQ=
+golang.org/x/time v0.0.0-20210723032227-1f47c861a9ac h1:7zkz7BUtwNFFqcowJ+RIgu2MaV/MapERkDIy+mwPyjs=
+golang.org/x/time v0.0.0-20210723032227-1f47c861a9ac/go.mod h1:tRJNPiyCQ0inRvYxbN9jk5I+vvW/OXSQhTDSoE431IQ=
 golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
 golang.org/x/tools v0.0.0-20190114222345-bf090417da8b/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
 golang.org/x/tools v0.0.0-20190226205152-f727befe758c/go.mod h1:9Yl7xja0Znq3iFh3HoIrodX9oNMXvdceNzlUR8zjMvY=
diff --git a/util/flowcontrol/throttle_test.go b/util/flowcontrol/throttle_test.go
index e48ad51bb3..81fea2b499 100644
--- a/util/flowcontrol/throttle_test.go
+++ b/util/flowcontrol/throttle_test.go
@@ -171,3 +171,37 @@ func TestWait(t *testing.T) {
 		t.Log(fmt.Sprintf("wait err: %v", err))
 	}
 }
+
+type fakeClock struct {
+	now time.Time
+}
+
+func newFakeClock() *fakeClock {
+	return &fakeClock{
+		now: time.Date(2000, 1, 1, 0, 0, 0, 0, time.UTC),
+	}
+}
+
+func (fc *fakeClock) Now() time.Time {
+	return fc.now
+}
+
+func (fc *fakeClock) Sleep(d time.Duration) {
+	fc.now = fc.now.Add(d)
+}
+
+func TestRatePrecisionBug(t *testing.T) {
+	// golang.org/x/time/rate used to have bugs around precision and this
+	// proves that they don't recur (at least in the form we know about).  This
+	// case is specifically designed to trigger the problem after 14 seconds.
+	qps := float32(time.Second) / float32(1031425*time.Microsecond)
+	clock := newFakeClock()
+	tb := NewTokenBucketRateLimiterWithClock(qps, 1, clock)
+
+	for i := 0; i < 60; i++ {
+		if !tb.TryAccept() {
+			t.Fatalf("failed after %d seconds", i*2)
+		}
+		clock.Sleep(2 * time.Second)
+	}
+}