fix(lint): remove uses of deprecated rand.Read (#2858)

Lint fixes in preparation for moving to Go 1.20

Remove deprecated calls to `rand.Seed`
In Go 1.20 the default generator is seeded randomly at program startup,
which is the desired behavior for these tests.

Remove uses of deprecated rand.Read: replace with calls to rand.Uint64()

Remove deprecated uses of rand.Read in content manager tests and
S3 versioned tests.
Adds a concurrency-safe helpers to provide functionality similar to that
provided by `rand.Read(b []byte) (int, error)`

internal/epoch/epoch_manager_test.go

@@ -173,14 +173,11 @@ func TestIndexEpochManager_Parallel(t *testing.T) {
 
 				indexNum++
 
-				var rnd [8]byte
-
-				rand.Read(rnd[:])
-
+				rnd := rand.Uint64()
 				ndx := newFakeIndexWithEntries(indexNum)
 
 				if _, err := te2.mgr.WriteIndex(ctx, map[blob.ID]blob.Bytes{
-					blob.ID(fmt.Sprintf("w%vr%x", worker, rnd)): gather.FromSlice(ndx.Bytes()),
+					blob.ID(fmt.Sprintf("w%vr%0x", worker, rnd)): gather.FromSlice(ndx.Bytes()),
 				}); err != nil {
 					if errors.Is(err, ErrVerySlowIndexWrite) {
 						indexNum--
@@ -713,17 +710,12 @@ func (te *epochManagerTestEnv) getMergedIndexContents(ctx context.Context, blobI
 
 func (te *epochManagerTestEnv) writeIndexFiles(ctx context.Context, ndx ...*fakeIndex) ([]blob.Metadata, error) {
 	shards := map[blob.ID]blob.Bytes{}
-
-	var sessionID [8]byte
-
-	rand.Read(sessionID[:])
+	sessionID := rand.Uint64()
 
 	for _, n := range ndx {
-		var rnd [8]byte
+		rnd := rand.Uint64()
 
-		rand.Read(rnd[:])
-
-		shards[blob.ID(fmt.Sprintf("%x-c%v-s%x", rnd[:], len(ndx), sessionID))] = gather.FromSlice(n.Bytes())
+		shards[blob.ID(fmt.Sprintf("%0x-c%v-s%0x", rnd, len(ndx), sessionID))] = gather.FromSlice(n.Bytes())
 	}
 
 	return te.mgr.WriteIndex(ctx, shards)

repo/blob/s3/s3_versioned_test.go

@@ -9,6 +9,7 @@
 	"math/rand"
 	"path"
 	"sort"
+	"sync"
 	"testing"
 	"time"
 
@@ -640,12 +641,29 @@ func randHex(tb testing.TB, length int) string {
 		return fmt.Sprintf("%0x", rand.Uint64())[0:length]
 	}
 
+	return randLongHex(tb, length)
+}
+
+// Protects the initialization of a random number generator for byte sequences
+// that are larger than 16 characters (8 bytes)
+// Notice that this is not a crypto RNG.
+var (
+	rMu sync.Mutex
+	r   = rand.New(rand.NewSource(clock.Now().UnixNano()))
+)
+
+func randLongHex(tb testing.TB, length int) string {
+	tb.Helper()
+
 	byteLength := (length + 1) / 2
 	b := make([]byte, byteLength)
-	n, err := rand.Read(b)
+
+	rMu.Lock()
+	n, err := r.Read(b)
+	rMu.Unlock()
 
 	require.NoError(tb, err)
-	require.Equal(tb, byteLength, n, "unexpected number of bytes from rand.Read")
+	require.Equal(tb, byteLength, n, "unexpected number of bytes while reading RNG")
 
 	return hex.EncodeToString(b)[:length]
 }

repo/content/content_manager_test.go

@@ -2083,7 +2083,7 @@ func (s *contentManagerSuite) TestCompression_NonCompressibleData(t *testing.T)
 	nonCompressibleData := make([]byte, 65000)
 	headerID := compression.ByName["pgzip"].HeaderID()
 
-	rand.Read(nonCompressibleData)
+	randRead(nonCompressibleData)
 
 	cid, err := bm.WriteContent(ctx, gather.FromSlice(nonCompressibleData), "", headerID)
 	require.NoError(t, err)
@@ -2630,7 +2630,7 @@ func makeRandomHexID(t *testing.T, length int) index.ID {
 	t.Helper()
 
 	b := make([]byte, length/2)
-	if _, err := rand.Read(b); err != nil {
+	if _, err := randRead(b); err != nil {
 		t.Fatal("Could not read random bytes", err)
 	}
 
@@ -2681,3 +2681,16 @@ type withDeleted struct {
 func (o withDeleted) GetDeleted() bool {
 	return o.deleted
 }
+
+var (
+	r   = rand.New(rand.NewSource(rand.Int63()))
+	rMu sync.Mutex
+)
+
+func randRead(b []byte) (n int, err error) {
+	rMu.Lock()
+	n, err = r.Read(b)
+	rMu.Unlock()
+
+	return
+}

repo/content/indexblob/index_blob_manager_v0_test.go

@@ -167,8 +167,6 @@ func TestIndexBlobManagerStress(t *testing.T) {
 		return
 	}
 
-	rand.Seed(clock.Now().UnixNano())
-
 	for i := range actionsTestIndexBlobManagerStress {
 		actionsTestIndexBlobManagerStress[i].weight = rand.Intn(100)
 		t.Logf("weight[%v] = %v", i, actionsTestIndexBlobManagerStress[i].weight)
@@ -268,8 +266,6 @@ func TestIndexBlobManagerStress(t *testing.T) {
 }
 
 func TestIndexBlobManagerPreventsResurrectOfDeletedContents(t *testing.T) {
-	rand.Seed(clock.Now().UnixNano())
-
 	// the test is randomized and runs very quickly, run it lots of times
 	failed := false
 	for i := 0; i < 100 && !failed; i++ {
@@ -282,8 +278,6 @@ func TestIndexBlobManagerPreventsResurrectOfDeletedContents(t *testing.T) {
 }
 
 func TestCompactionCreatesPreviousIndex(t *testing.T) {
-	rand.Seed(clock.Now().UnixNano())
-
 	storageData := blobtesting.DataMap{}
 
 	fakeTime := faketime.NewTimeAdvance(fakeLocalStartTime, 0)
@@ -333,8 +327,6 @@ func TestCompactionCreatesPreviousIndex(t *testing.T) {
 }
 
 func TestIndexBlobManagerPreventsResurrectOfDeletedContents_RandomizedTimings(t *testing.T) {
-	rand.Seed(clock.Now().UnixNano())
-
 	numAttempts := 1000
 	if testutil.ShouldReduceTestComplexity() {
 		numAttempts = 100

repo/object/object_manager_test.go

@@ -18,7 +18,6 @@
 	"github.com/stretchr/testify/require"
 	"golang.org/x/sync/errgroup"
 
-	"github.com/kopia/kopia/internal/clock"
 	"github.com/kopia/kopia/internal/gather"
 	"github.com/kopia/kopia/internal/impossible"
 	"github.com/kopia/kopia/internal/testlogging"
@@ -273,8 +272,6 @@ func TestCheckpointing(t *testing.T) {
 }
 
 func TestObjectWriterRaceBetweenCheckpointAndResult(t *testing.T) {
-	rand.Seed(clock.Now().UnixNano())
-
 	ctx := testlogging.Context(t)
 	data := map[content.ID][]byte{}
 	fcm := &fakeContentManager{

tests/repository_stress_test/repository_stress_test.go

@@ -78,10 +78,6 @@ type StressOptions struct {
 
 const masterPassword = "foo-bar-baz-1234"
 
-func init() {
-	rand.Seed(clock.Now().UnixNano())
-}
-
 func TestStressRepositoryMixAll(t *testing.T) {
 	runStress(t, &StressOptions{
 		ConfigsPerRepository:      2,