From f6ad4dcef54c5ce997a4bad5a6d86de229015700 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Tue, 16 Apr 2024 21:25:22 +0200 Subject: Adding upstream version 1.22.1. Signed-off-by: Daniel Baumann --- src/sync/oncefunc_test.go | 315 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 315 insertions(+) create mode 100644 src/sync/oncefunc_test.go (limited to 'src/sync/oncefunc_test.go') diff --git a/src/sync/oncefunc_test.go b/src/sync/oncefunc_test.go new file mode 100644 index 0000000..5f0d564 --- /dev/null +++ b/src/sync/oncefunc_test.go @@ -0,0 +1,315 @@ +// Copyright 2022 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package sync_test + +import ( + "bytes" + "math" + "runtime" + "runtime/debug" + "sync" + "sync/atomic" + "testing" + _ "unsafe" +) + +// We assume that the Once.Do tests have already covered parallelism. + +func TestOnceFunc(t *testing.T) { + calls := 0 + f := sync.OnceFunc(func() { calls++ }) + allocs := testing.AllocsPerRun(10, f) + if calls != 1 { + t.Errorf("want calls==1, got %d", calls) + } + if allocs != 0 { + t.Errorf("want 0 allocations per call, got %v", allocs) + } +} + +func TestOnceValue(t *testing.T) { + calls := 0 + f := sync.OnceValue(func() int { + calls++ + return calls + }) + allocs := testing.AllocsPerRun(10, func() { f() }) + value := f() + if calls != 1 { + t.Errorf("want calls==1, got %d", calls) + } + if value != 1 { + t.Errorf("want value==1, got %d", value) + } + if allocs != 0 { + t.Errorf("want 0 allocations per call, got %v", allocs) + } +} + +func TestOnceValues(t *testing.T) { + calls := 0 + f := sync.OnceValues(func() (int, int) { + calls++ + return calls, calls + 1 + }) + allocs := testing.AllocsPerRun(10, func() { f() }) + v1, v2 := f() + if calls != 1 { + t.Errorf("want calls==1, got %d", calls) + } + if v1 != 1 || v2 != 2 { + t.Errorf("want v1==1 and v2==2, got %d and %d", v1, v2) + } + if allocs != 0 { + t.Errorf("want 0 allocations per call, got %v", allocs) + } +} + +func testOncePanicX(t *testing.T, calls *int, f func()) { + testOncePanicWith(t, calls, f, func(label string, p any) { + if p != "x" { + t.Fatalf("%s: want panic %v, got %v", label, "x", p) + } + }) +} + +func testOncePanicWith(t *testing.T, calls *int, f func(), check func(label string, p any)) { + // Check that the each call to f panics with the same value, but the + // underlying function is only called once. + for _, label := range []string{"first time", "second time"} { + var p any + panicked := true + func() { + defer func() { + p = recover() + }() + f() + panicked = false + }() + if !panicked { + t.Fatalf("%s: f did not panic", label) + } + check(label, p) + } + if *calls != 1 { + t.Errorf("want calls==1, got %d", *calls) + } +} + +func TestOnceFuncPanic(t *testing.T) { + calls := 0 + f := sync.OnceFunc(func() { + calls++ + panic("x") + }) + testOncePanicX(t, &calls, f) +} + +func TestOnceValuePanic(t *testing.T) { + calls := 0 + f := sync.OnceValue(func() int { + calls++ + panic("x") + }) + testOncePanicX(t, &calls, func() { f() }) +} + +func TestOnceValuesPanic(t *testing.T) { + calls := 0 + f := sync.OnceValues(func() (int, int) { + calls++ + panic("x") + }) + testOncePanicX(t, &calls, func() { f() }) +} + +func TestOnceFuncPanicNil(t *testing.T) { + calls := 0 + f := sync.OnceFunc(func() { + calls++ + panic(nil) + }) + testOncePanicWith(t, &calls, f, func(label string, p any) { + switch p.(type) { + case nil, *runtime.PanicNilError: + return + } + t.Fatalf("%s: want nil panic, got %v", label, p) + }) +} + +func TestOnceFuncGoexit(t *testing.T) { + // If f calls Goexit, the results are unspecified. But check that f doesn't + // get called twice. + calls := 0 + f := sync.OnceFunc(func() { + calls++ + runtime.Goexit() + }) + var wg sync.WaitGroup + for i := 0; i < 2; i++ { + wg.Add(1) + go func() { + defer wg.Done() + defer func() { recover() }() + f() + }() + wg.Wait() + } + if calls != 1 { + t.Errorf("want calls==1, got %d", calls) + } +} + +func TestOnceFuncPanicTraceback(t *testing.T) { + // Test that on the first invocation of a OnceFunc, the stack trace goes all + // the way to the origin of the panic. + f := sync.OnceFunc(onceFuncPanic) + + defer func() { + if p := recover(); p != "x" { + t.Fatalf("want panic %v, got %v", "x", p) + } + stack := debug.Stack() + want := "sync_test.onceFuncPanic" + if !bytes.Contains(stack, []byte(want)) { + t.Fatalf("want stack containing %v, got:\n%s", want, string(stack)) + } + }() + f() +} + +func onceFuncPanic() { + panic("x") +} + +func TestOnceXGC(t *testing.T) { + fns := map[string]func([]byte) func(){ + "OnceFunc": func(buf []byte) func() { + return sync.OnceFunc(func() { buf[0] = 1 }) + }, + "OnceValue": func(buf []byte) func() { + f := sync.OnceValue(func() any { buf[0] = 1; return nil }) + return func() { f() } + }, + "OnceValues": func(buf []byte) func() { + f := sync.OnceValues(func() (any, any) { buf[0] = 1; return nil, nil }) + return func() { f() } + }, + } + for n, fn := range fns { + t.Run(n, func(t *testing.T) { + buf := make([]byte, 1024) + var gc atomic.Bool + runtime.SetFinalizer(&buf[0], func(_ *byte) { + gc.Store(true) + }) + f := fn(buf) + gcwaitfin() + if gc.Load() != false { + t.Fatal("wrapped function garbage collected too early") + } + f() + gcwaitfin() + if gc.Load() != true { + // Even if f is still alive, the function passed to Once(Func|Value|Values) + // is not kept alive after the first call to f. + t.Fatal("wrapped function should be garbage collected, but still live") + } + f() + }) + } +} + +// gcwaitfin performs garbage collection and waits for all finalizers to run. +func gcwaitfin() { + runtime.GC() + runtime_blockUntilEmptyFinalizerQueue(math.MaxInt64) +} + +//go:linkname runtime_blockUntilEmptyFinalizerQueue runtime.blockUntilEmptyFinalizerQueue +func runtime_blockUntilEmptyFinalizerQueue(int64) bool + +var ( + onceFunc = sync.OnceFunc(func() {}) + + onceFuncOnce sync.Once +) + +func doOnceFunc() { + onceFuncOnce.Do(func() {}) +} + +func BenchmarkOnceFunc(b *testing.B) { + b.Run("v=Once", func(b *testing.B) { + b.ReportAllocs() + for i := 0; i < b.N; i++ { + // The baseline is direct use of sync.Once. + doOnceFunc() + } + }) + b.Run("v=Global", func(b *testing.B) { + b.ReportAllocs() + for i := 0; i < b.N; i++ { + // As of 3/2023, the compiler doesn't recognize that onceFunc is + // never mutated and is a closure that could be inlined. + // Too bad, because this is how OnceFunc will usually be used. + onceFunc() + } + }) + b.Run("v=Local", func(b *testing.B) { + b.ReportAllocs() + // As of 3/2023, the compiler *does* recognize this local binding as an + // inlinable closure. This is the best case for OnceFunc, but probably + // not typical usage. + f := sync.OnceFunc(func() {}) + for i := 0; i < b.N; i++ { + f() + } + }) +} + +var ( + onceValue = sync.OnceValue(func() int { return 42 }) + + onceValueOnce sync.Once + onceValueValue int +) + +func doOnceValue() int { + onceValueOnce.Do(func() { + onceValueValue = 42 + }) + return onceValueValue +} + +func BenchmarkOnceValue(b *testing.B) { + // See BenchmarkOnceFunc + b.Run("v=Once", func(b *testing.B) { + b.ReportAllocs() + for i := 0; i < b.N; i++ { + if want, got := 42, doOnceValue(); want != got { + b.Fatalf("want %d, got %d", want, got) + } + } + }) + b.Run("v=Global", func(b *testing.B) { + b.ReportAllocs() + for i := 0; i < b.N; i++ { + if want, got := 42, onceValue(); want != got { + b.Fatalf("want %d, got %d", want, got) + } + } + }) + b.Run("v=Local", func(b *testing.B) { + b.ReportAllocs() + onceValue := sync.OnceValue(func() int { return 42 }) + for i := 0; i < b.N; i++ { + if want, got := 42, onceValue(); want != got { + b.Fatalf("want %d, got %d", want, got) + } + } + }) +} -- cgit v1.2.3