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sync: remove TestWaitGroupMisuse2 and TestWaitGroupMisuse3
These tests are inherently nondeterministic: They exercise a racy code path for up to one million iterations, and require that an error occur at least once. TestWaitGroupMisuse2 in particular is an ongoing source of trybot flakiness. Fixes #38163. Change-Id: Ibbbda2c998c915333487ad262d3df6829de01c2b Reviewed-on: https://go-review.googlesource.com/c/go/+/340249 Trust: Damien Neil <[email protected]> Trust: Dmitri Shuralyov <[email protected]> Run-TryBot: Damien Neil <[email protected]> TryBot-Result: Go Bot <[email protected]> Reviewed-by: Dmitry Vyukov <[email protected]>
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‎src/sync/waitgroup_test.go‎

Lines changed: 0 additions & 126 deletions
Original file line numberDiff line numberDiff line change
@@ -5,8 +5,6 @@
55
package sync_test
66

77
import (
8-
"internal/race"
9-
"runtime"
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. "sync"
119
"sync/atomic"
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"testing"
@@ -48,12 +46,6 @@ func TestWaitGroup(t *testing.T) {
4846
}
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}
5048

51-
func knownRacy(t *testing.T) {
52-
if race.Enabled {
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t.Skip("skipping known-racy test under the race detector")
54-
}
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}
56-
5749
func TestWaitGroupMisuse(t *testing.T) {
5850
defer func() {
5951
err := recover()
@@ -68,124 +60,6 @@ func TestWaitGroupMisuse(t *testing.T) {
6860
t.Fatal("Should panic")
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}
7062

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// pollUntilEqual blocks until v, loaded atomically, is
72-
// equal to the target.
73-
func pollUntilEqual(v *uint32, target uint32) {
74-
for {
75-
for i := 0; i < 1e3; i++ {
76-
if atomic.LoadUint32(v) == target {
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return
78-
}
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}
80-
// yield to avoid deadlock with the garbage collector
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// see issue #20072
82-
runtime.Gosched()
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}
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}
85-
86-
func TestWaitGroupMisuse2(t *testing.T) {
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knownRacy(t)
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if runtime.NumCPU() <= 4 {
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t.Skip("NumCPU<=4, skipping: this test requires parallelism")
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}
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defer func() {
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err := recover()
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if err != "sync: negative WaitGroup counter" &&
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err != "sync: WaitGroup misuse: Add called concurrently with Wait" &&
95-
err != "sync: WaitGroup is reused before previous Wait has returned" {
96-
t.Fatalf("Unexpected panic: %#v", err)
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}
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}()
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defer runtime.GOMAXPROCS(runtime.GOMAXPROCS(4))
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done := make(chan interface{}, 2)
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// The detection is opportunistic, so we want it to panic
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// at least in one run out of a million.
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for i := 0; i < 1e6; i++ {
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var wg WaitGroup
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var here uint32
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wg.Add(1)
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go func() {
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defer func() {
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done <- recover()
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}()
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atomic.AddUint32(&here, 1)
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pollUntilEqual(&here, 3)
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wg.Wait()
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}()
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go func() {
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defer func() {
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done <- recover()
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}()
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atomic.AddUint32(&here, 1)
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pollUntilEqual(&here, 3)
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wg.Add(1) // This is the bad guy.
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wg.Done()
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}()
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atomic.AddUint32(&here, 1)
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pollUntilEqual(&here, 3)
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wg.Done()
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for j := 0; j < 2; j++ {
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if err := <-done; err != nil {
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panic(err)
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}
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}
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}
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t.Fatal("Should panic")
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}
135-
136-
func TestWaitGroupMisuse3(t *testing.T) {
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knownRacy(t)
138-
if runtime.NumCPU() <= 1 {
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t.Skip("NumCPU==1, skipping: this test requires parallelism")
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}
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defer func() {
142-
err := recover()
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if err != "sync: negative WaitGroup counter" &&
144-
err != "sync: WaitGroup misuse: Add called concurrently with Wait" &&
145-
err != "sync: WaitGroup is reused before previous Wait has returned" {
146-
t.Fatalf("Unexpected panic: %#v", err)
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}
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}()
149-
defer runtime.GOMAXPROCS(runtime.GOMAXPROCS(4))
150-
done := make(chan interface{}, 3)
151-
// The detection is opportunistically, so we want it to panic
152-
// at least in one run out of a million.
153-
for i := 0; i < 1e6; i++ {
154-
var wg WaitGroup
155-
wg.Add(1)
156-
go func() {
157-
defer func() {
158-
done <- recover()
159-
}()
160-
wg.Done()
161-
}()
162-
go func() {
163-
defer func() {
164-
done <- recover()
165-
}()
166-
wg.Wait()
167-
// Start reusing the wg before waiting for the Wait below to return.
168-
wg.Add(1)
169-
go func() {
170-
wg.Done()
171-
}()
172-
wg.Wait()
173-
}()
174-
go func() {
175-
defer func() {
176-
done <- recover()
177-
}()
178-
wg.Wait()
179-
}()
180-
for j := 0; j < 3; j++ {
181-
if err := <-done; err != nil {
182-
panic(err)
183-
}
184-
}
185-
}
186-
t.Fatal("Should panic")
187-
}
188-
18963
func TestWaitGroupRace(t *testing.T) {
19064
// Run this test for about 1ms.
19165
for i := 0; i < 1000; i++ {

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