From: Russ Cox <rsc@golang.org>
Date: Tue, 25 Oct 2022 16:53:30 +0000 (-0400)
Subject: all: remove uses of rand.Seed
X-Git-Tag: go1.20rc1~528
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=3afba3124df90f1b2f56d3324793f16649a2d93a;p=gostls13.git

all: remove uses of rand.Seed

As of CL 443058, rand.Seed is not necessary to call,
nor is it a particular good idea.

For #54880.

Change-Id: If9d70763622c09008599db8c97a90fcbe285c6f8
Reviewed-on: https://go-review.googlesource.com/c/go/+/445395
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
Auto-Submit: Russ Cox <rsc@golang.org>
Reviewed-by: Ian Lance Taylor <iant@google.com>
---

diff --git a/src/cmd/compile/internal/ssagen/pgen.go b/src/cmd/compile/internal/ssagen/pgen.go
index 9aaf4b81e0..7e7c13adc9 100644
--- a/src/cmd/compile/internal/ssagen/pgen.go
+++ b/src/cmd/compile/internal/ssagen/pgen.go
@@ -6,11 +6,8 @@ package ssagen
 
 import (
 	"internal/buildcfg"
-	"internal/race"
-	"math/rand"
 	"sort"
 	"sync"
-	"time"
 
 	"cmd/compile/internal/base"
 	"cmd/compile/internal/ir"
@@ -214,12 +211,6 @@ func Compile(fn *ir.Func, worker int) {
 	fieldtrack(pp.Text.From.Sym, fn.FieldTrack)
 }
 
-func init() {
-	if race.Enabled {
-		rand.Seed(time.Now().UnixNano())
-	}
-}
-
 // StackOffset returns the stack location of a LocalSlot relative to the
 // stack pointer, suitable for use in a DWARF location entry. This has nothing
 // to do with its offset in the user variable.
diff --git a/src/crypto/rand/rand_batched_test.go b/src/crypto/rand/rand_batched_test.go
index 89953776a8..02f48931e3 100644
--- a/src/crypto/rand/rand_batched_test.go
+++ b/src/crypto/rand/rand_batched_test.go
@@ -8,7 +8,6 @@ package rand
 
 import (
 	"bytes"
-	"encoding/binary"
 	"errors"
 	prand "math/rand"
 	"testing"
@@ -33,10 +32,6 @@ func TestBatched(t *testing.T) {
 }
 
 func TestBatchedBuffering(t *testing.T) {
-	var prandSeed [8]byte
-	Read(prandSeed[:])
-	prand.Seed(int64(binary.LittleEndian.Uint64(prandSeed[:])))
-
 	backingStore := make([]byte, 1<<23)
 	prand.Read(backingStore)
 	backingMarker := backingStore[:]
diff --git a/src/math/rand/example_test.go b/src/math/rand/example_test.go
index f691e39d64..d656f470eb 100644
--- a/src/math/rand/example_test.go
+++ b/src/math/rand/example_test.go
@@ -16,10 +16,6 @@ import (
 // the output of the random number generator when given a fixed seed.
 
 func Example() {
-	// Seeding with the same value results in the same random sequence each run.
-	// For different numbers, seed with a different value, such as
-	// time.Now().UnixNano(), which yields a constantly-changing number.
-	rand.Seed(42)
 	answers := []string{
 		"It is certain",
 		"It is decidedly so",
@@ -43,7 +39,6 @@ func Example() {
 		"Very doubtful",
 	}
 	fmt.Println("Magic 8-Ball says:", answers[rand.Intn(len(answers))])
-	// Output: Magic 8-Ball says: As I see it yes
 }
 
 // This example shows the use of each of the methods on a *Rand.
@@ -116,9 +111,6 @@ func ExampleShuffle() {
 		words[i], words[j] = words[j], words[i]
 	})
 	fmt.Println(words)
-
-	// Output:
-	// [mouth my the of runs corners from ink]
 }
 
 func ExampleShuffle_slicesInUnison() {
@@ -132,26 +124,10 @@ func ExampleShuffle_slicesInUnison() {
 	for i := range numbers {
 		fmt.Printf("%c: %c\n", letters[i], numbers[i])
 	}
-
-	// Output:
-	// C: 3
-	// D: 4
-	// A: 1
-	// E: 5
-	// B: 2
 }
 
 func ExampleIntn() {
-	// Seeding with the same value results in the same random sequence each run.
-	// For different numbers, seed with a different value, such as
-	// time.Now().UnixNano(), which yields a constantly-changing number.
-	rand.Seed(86)
 	fmt.Println(rand.Intn(100))
 	fmt.Println(rand.Intn(100))
 	fmt.Println(rand.Intn(100))
-
-	// Output:
-	// 42
-	// 76
-	// 30
 }
diff --git a/src/strconv/atof_test.go b/src/strconv/atof_test.go
index aa587a473c..7b287b4219 100644
--- a/src/strconv/atof_test.go
+++ b/src/strconv/atof_test.go
@@ -12,7 +12,6 @@ import (
 	"strings"
 	"sync"
 	"testing"
-	"time"
 )
 
 type atofTest struct {
@@ -463,7 +462,6 @@ func initAtofOnce() {
 	}
 
 	// Generate random inputs for tests and benchmarks
-	rand.Seed(time.Now().UnixNano())
 	if testing.Short() {
 		atofRandomTests = make([]atofSimpleTest, 100)
 	} else {